diff --git a/docs/plans/2026-05-20-auditlog-m6-reconciliation-purge.md b/docs/plans/2026-05-20-auditlog-m6-reconciliation-purge.md
new file mode 100644
index 0000000..aebaf93
--- /dev/null
+++ b/docs/plans/2026-05-20-auditlog-m6-reconciliation-purge.md
@@ -0,0 +1,19 @@
+# Audit Log #23 — M6 Reconciliation + Purge + Partition Maintenance + Health Metrics
+
+> **For Claude:** subagent-driven-development with bundled cadence.
+
+**Goal:** Self-healing telemetry (5-min reconciliation pull), monthly partition rollover, daily partition-switch purge with drop-and-rebuild around UX_AuditLog_EventId, all five health metrics live (SiteAuditBacklog, SiteAuditWriteFailures, SiteAuditTelemetryStalled, CentralAuditWriteFailures, AuditRedactionFailure).
+
+**M5 realities baked in:** AuditRedactionFailure counter is site-only — M6-T9 surfaces it centrally. SwitchOutPartitionAsync ships as NotSupportedException stub from M1; M6-T4 replaces it with the drop-DROP-INDEX → SWITCH PARTITION → DROP staging → CREATE UNIQUE NONCLUSTERED INDEX dance. Partition function pre-seeded Jan 2026 – Dec 2027; M6-T5 SPLITs new boundaries forward.
+
+**Bundles:**
+- Bundle A — Proto + site handler (T1, T2)
+- Bundle B — Reconciliation actor (T3)
+- Bundle C — Purge actor + drop-and-rebuild repository fix (T4)
+- Bundle D — Partition maintenance hosted service (T5)
+- Bundle E — Health metrics (T6, T7, T8, T9)
+- Bundle F — Integration tests (T10, T11, T12)
+
+Final cross-bundle review + merge.
+
+**Note**: M2 noted NoOpSiteStreamAuditClient stays in production until "M6 wires the real client". M6-T1+T2 add the PULL RPC; the actual production PUSH client (real implementation of ISiteStreamAuditClient.IngestAuditEventsAsync + IngestCachedTelemetryAsync) is the bigger lift. M6 will add the real client IF feasible within scope OR defer to a follow-up. Decision: try in Bundle A (alongside the proto extension); if scope blows up, the NoOp stays.
diff --git a/src/ScadaLink.AuditLog/Central/AuditCentralHealthSnapshot.cs b/src/ScadaLink.AuditLog/Central/AuditCentralHealthSnapshot.cs
new file mode 100644
index 0000000..e728c51
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditCentralHealthSnapshot.cs
@@ -0,0 +1,80 @@
+using System.Collections.Concurrent;
+using ScadaLink.AuditLog.Payload;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Audit Log (#23) M6 Bundle E (T8, T9) — central singleton implementation of
+/// . Owns thread-safe
+/// counters for
+/// CentralAuditWriteFailures + AuditRedactionFailure and a
+/// per-site latched stalled-state map fed by the
+/// . Also implements the
+/// writer surfaces ( +
+/// ) so a single concrete object
+/// is the source of truth — DI binds those two interfaces to this same
+/// singleton instance on the central composition root.
+///
+///
+///
+/// Why one type for read + write. The writer interfaces are tiny
+/// (Increment()) and the read surface needs visibility of those
+/// counters anyway — having a single class own both means the
+/// Interlocked field IS the snapshot value, no extra plumbing needed.
+/// Mirrors the
+/// pattern where
+/// the collector both receives and exposes the metric.
+///
+///
+/// Stalled-state plumbing. The per-site stalled latch lives directly
+/// on this snapshot. is the
+/// EventStream subscriber that pushes
+/// publications in via
+/// . Keeping the dictionary on this type (rather
+/// than reading the tracker on every access) lets the snapshot be constructed
+/// without an dependency — the tracker
+/// is wired up later from the Akka bootstrap, once the system is built.
+///
+///
+public sealed class AuditCentralHealthSnapshot
+ : IAuditCentralHealthSnapshot,
+ ICentralAuditWriteFailureCounter,
+ IAuditRedactionFailureCounter
+{
+ private int _centralAuditWriteFailures;
+ private int _auditRedactionFailure;
+ private readonly ConcurrentDictionary _stalled = new();
+
+ ///
+ public int CentralAuditWriteFailures =>
+ Interlocked.CompareExchange(ref _centralAuditWriteFailures, 0, 0);
+
+ ///
+ public int AuditRedactionFailure =>
+ Interlocked.CompareExchange(ref _auditRedactionFailure, 0, 0);
+
+ ///
+ public IReadOnlyDictionary SiteAuditTelemetryStalled =>
+ new Dictionary(_stalled);
+
+ ///
+ /// Apply a publication
+ /// observed by . Public
+ /// so the tracker (which lives in the same assembly but is constructed
+ /// later from the Akka host) can push without a friend reference;
+ /// readers should call .
+ ///
+ public void ApplyStalled(SiteAuditTelemetryStalledChanged evt)
+ {
+ if (evt is null) return;
+ _stalled[evt.SiteId] = evt.Stalled;
+ }
+
+ ///
+ void ICentralAuditWriteFailureCounter.Increment() =>
+ Interlocked.Increment(ref _centralAuditWriteFailures);
+
+ ///
+ void IAuditRedactionFailureCounter.Increment() =>
+ Interlocked.Increment(ref _auditRedactionFailure);
+}
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogIngestActor.cs b/src/ScadaLink.AuditLog/Central/AuditLogIngestActor.cs
index 8e7f21b..61a6daf 100644
--- a/src/ScadaLink.AuditLog/Central/AuditLogIngestActor.cs
+++ b/src/ScadaLink.AuditLog/Central/AuditLogIngestActor.cs
@@ -124,6 +124,7 @@ public class AuditLogIngestActor : ReceiveActor
IServiceScope? scope = null;
IAuditLogRepository repository;
IAuditPayloadFilter? filter = null;
+ ICentralAuditWriteFailureCounter? failureCounter = null;
if (_injectedRepository is not null)
{
repository = _injectedRepository;
@@ -133,6 +134,10 @@ public class AuditLogIngestActor : ReceiveActor
scope = _serviceProvider!.CreateScope();
repository = scope.ServiceProvider.GetRequiredService();
filter = scope.ServiceProvider.GetService();
+ // M6 Bundle E (T8): central health counter is best-effort —
+ // unregistered (test composition roots) means the per-row catch
+ // simply logs without surfacing on the health dashboard.
+ failureCounter = scope.ServiceProvider.GetService();
}
try
@@ -157,6 +162,10 @@ public class AuditLogIngestActor : ReceiveActor
{
// Per-row catch — one bad row never sinks the whole batch.
// The row stays Pending at the site; the next drain retries.
+ // M6 Bundle E (T8): bump the central health counter so a
+ // sustained insert-throw failure surfaces on the dashboard.
+ try { failureCounter?.Increment(); }
+ catch { /* counter must never throw — defence in depth */ }
_logger.LogError(ex,
"Failed to persist audit event {EventId} during batch ingest; row will be retried by the site.",
evt.EventId);
@@ -204,6 +213,10 @@ public class AuditLogIngestActor : ReceiveActor
// never throw, so we can apply it inside the per-entry try
// without risking an unbounded blast radius.
var filter = scope.ServiceProvider.GetService();
+ // M6 Bundle E (T8): same best-effort central health counter as
+ // the OnIngestAsync path — null on test composition roots that
+ // skip the registration.
+ var failureCounter = scope.ServiceProvider.GetService();
foreach (var entry in cmd.Entries)
{
@@ -240,6 +253,10 @@ public class AuditLogIngestActor : ReceiveActor
// EventId is NOT added to `accepted` so the site keeps its
// row Pending and retries on the next drain. Other entries
// in the batch continue with their own transactions.
+ // M6 Bundle E (T8): bump the central health counter so a
+ // sustained dual-write failure surfaces on the dashboard.
+ try { failureCounter?.Increment(); }
+ catch { /* counter must never throw — defence in depth */ }
_logger.LogError(
ex,
"Combined telemetry dual-write failed for AuditEvent {EventId} / TrackedOperationId {TrackedOpId}; rolled back.",
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceOptions.cs b/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceOptions.cs
new file mode 100644
index 0000000..317e6e7
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceOptions.cs
@@ -0,0 +1,37 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Tuning knobs for the central
+/// hosted service (M6-T5).
+/// Defaults: once every 24 hours, keep at least one future monthly
+/// boundary ahead of .
+///
+///
+///
+/// The hosted service drives a daily roll-forward of
+/// pf_AuditLog_Month: each tick reads the current max boundary and
+/// SPLITs new monthly boundaries until at least
+/// future months are covered. The 1-month
+/// default is intentionally conservative — anything less risks an
+/// end-of-month race where inserts land in the unbounded tail partition;
+/// anything more wastes nothing but represents premature commitment.
+///
+///
+/// The 24-hour cadence is the cheapest interval that still guarantees
+/// at-most-one missed boundary in steady state (even a hard failover the
+/// hosted service can recover on its very next tick). Lowering this below
+/// an hour would generate more metadata churn than it saves.
+///
+///
+public sealed class AuditLogPartitionMaintenanceOptions
+{
+ /// Period of the maintenance tick in seconds (default 86 400 = 24 h).
+ public int IntervalSeconds { get; set; } = 86_400;
+
+ ///
+ /// Minimum number of future months that pf_AuditLog_Month must
+ /// cover after each tick. Default 1 — i.e. as of mid-May the partition
+ /// for the next full month (June) must already be present.
+ ///
+ public int LookaheadMonths { get; set; } = 1;
+}
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceService.cs b/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceService.cs
new file mode 100644
index 0000000..2aa02f8
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditLogPartitionMaintenanceService.cs
@@ -0,0 +1,145 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ScadaLink.Commons.Interfaces;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Central (M6-T5, Bundle D) that rolls
+/// pf_AuditLog_Month forward once a day. Each tick opens a fresh DI
+/// scope, resolves , and calls
+/// to SPLIT any
+/// missing future boundaries — the partition function must always cover at
+/// least
+/// future months, otherwise inserts past the highest boundary accumulate in
+/// a single unbounded tail partition that SwitchOutPartitionAsync
+/// cannot purge cleanly.
+///
+///
+///
+/// Why a hosted service, not an actor. Bundle C's
+/// sits inside the central singleton
+/// because it needs supervised lifecycle alongside the rest of the
+/// reconciliation / ingest pipeline. Roll-forward is genuinely a once-a-day
+/// chore with no cross-actor coordination, so we use the much simpler
+/// hosted-service pattern: Task.Run on start, Task.Delay
+/// between ticks, cancellation on stop. Reusing
+/// from the central node-only DI graph
+/// keeps the contract testable without any actor framework involvement.
+///
+///
+/// Failure containment. The tick body wraps the maintenance call in
+/// a try/catch so a transient SQL Server error never tears down the hosted
+/// service — the next tick simply retries. The exception is logged with
+/// the original stack trace at Error level; ops surfaces (M6 Bundle
+/// E's central health collector) can subscribe to the logger to alert on
+/// repeated failures.
+///
+///
+/// Startup ordering. A first tick fires immediately at
+/// so a fresh deployment doesn't need to wait
+/// for
+/// the partition function to come up to spec. This is also what the brief
+/// asks for ("Run once on startup").
+///
+///
+/// DI scope per tick. is scoped
+/// (alongside the rest of the EF repositories) because the implementation
+/// reuses the per-scope ScadaLinkDbContext. A hosted service is a
+/// singleton, so it must open and dispose a scope around each tick — the
+/// same pattern uses.
+///
+///
+public sealed class AuditLogPartitionMaintenanceService : IHostedService, IDisposable
+{
+ private readonly IServiceScopeFactory _scopeFactory;
+ private readonly IOptions _options;
+ private readonly ILogger _logger;
+ private CancellationTokenSource? _cts;
+ private Task? _loop;
+
+ public AuditLogPartitionMaintenanceService(
+ IServiceScopeFactory scopeFactory,
+ IOptions options,
+ ILogger logger)
+ {
+ _scopeFactory = scopeFactory ?? throw new ArgumentNullException(nameof(scopeFactory));
+ _options = options ?? throw new ArgumentNullException(nameof(options));
+ _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+ }
+
+ ///
+ public Task StartAsync(CancellationToken ct)
+ {
+ // Linked CTS lets StopAsync's cancellation AND the host's shutdown
+ // token both terminate the loop; either side firing aborts the
+ // pending Task.Delay.
+ _cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+ _loop = Task.Run(() => RunLoopAsync(_cts.Token));
+ return Task.CompletedTask;
+ }
+
+ private async Task RunLoopAsync(CancellationToken ct)
+ {
+ // Run once on startup so a fresh deployment isn't gated on the
+ // IntervalSeconds initial wait — the brief calls this out explicitly.
+ await SafeMaintainAsync(ct).ConfigureAwait(false);
+
+ while (!ct.IsCancellationRequested)
+ {
+ try
+ {
+ await Task.Delay(TimeSpan.FromSeconds(_options.Value.IntervalSeconds), ct)
+ .ConfigureAwait(false);
+ }
+ catch (OperationCanceledException)
+ {
+ break;
+ }
+
+ await SafeMaintainAsync(ct).ConfigureAwait(false);
+ }
+ }
+
+ private async Task SafeMaintainAsync(CancellationToken ct)
+ {
+ try
+ {
+ await using var scope = _scopeFactory.CreateAsyncScope();
+ var maintenance = scope.ServiceProvider.GetRequiredService();
+ var added = await maintenance
+ .EnsureLookaheadAsync(_options.Value.LookaheadMonths, ct)
+ .ConfigureAwait(false);
+ if (added.Count > 0)
+ {
+ _logger.LogInformation(
+ "AuditLogPartitionMaintenance added {Count} boundaries: {Boundaries}",
+ added.Count,
+ string.Join(", ", added.Select(b => b.ToString("yyyy-MM-dd"))));
+ }
+ }
+ catch (Exception ex)
+ {
+ // Catch-all is deliberate: the hosted service must survive every
+ // class of tick failure (transient SQL, DI resolution, etc.) so
+ // the next tick gets a chance. The brief's contract is
+ // "exception logged, not propagated".
+ _logger.LogError(ex, "AuditLogPartitionMaintenance tick failed");
+ }
+ }
+
+ ///
+ public Task StopAsync(CancellationToken ct)
+ {
+ _cts?.Cancel();
+ return _loop ?? Task.CompletedTask;
+ }
+
+ ///
+ public void Dispose()
+ {
+ _cts?.Dispose();
+ }
+}
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogPurgeActor.cs b/src/ScadaLink.AuditLog/Central/AuditLogPurgeActor.cs
new file mode 100644
index 0000000..153e238
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditLogPurgeActor.cs
@@ -0,0 +1,214 @@
+using System.Diagnostics;
+using Akka.Actor;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Configuration;
+using ScadaLink.Commons.Interfaces.Repositories;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Central singleton (M6 Bundle C) that drives the daily AuditLog partition
+/// purge. On a configurable timer (default 24 hours) the actor:
+///
+/// - Queries
+/// for monthly boundaries whose latest OccurredAtUtc is older
+/// than DateTime.UtcNow - RetentionDays.
+/// - For each eligible boundary, calls
+/// which runs
+/// the drop-and-rebuild dance around UX_AuditLog_EventId.
+/// - Publishes on the actor-system
+/// EventStream so the Bundle E central health collector + ops surfaces
+/// can subscribe without coupling to this actor.
+///
+///
+///
+///
+/// Daily cadence. Partition switch is metadata-only but the
+/// drop-and-rebuild dance briefly removes UX_AuditLog_EventId; running
+/// more often than necessary trades unique-index rebuild outages for
+/// negligible freshness wins. The default 24-hour interval matches
+/// alog.md §10's retention policy.
+///
+///
+/// Continue-on-error. A single boundary that throws (transient SQL
+/// failure, contention with backup, missing object) must NOT prevent the
+/// other eligible boundaries from being purged on the same tick. Per-boundary
+/// work runs inside its own try/catch; the actor's
+/// uses Resume so any leaked exception keeps
+/// the singleton alive for the next tick.
+///
+///
+/// DI scopes. is a scoped EF Core
+/// service registered by AddConfigurationDatabase. The singleton
+/// opens one DI scope per tick and reuses the same repository across every
+/// boundary in that tick — mirrors the
+/// pattern.
+///
+///
+/// EventStream. Publishing through
+/// the EventStream rather than direct messaging avoids coupling this actor
+/// to its consumers; M6 Bundle E will subscribe a central health-counter
+/// bridge that surfaces purge progress on the central health report.
+///
+///
+public class AuditLogPurgeActor : ReceiveActor
+{
+ private readonly IServiceProvider _services;
+ private readonly AuditLogPurgeOptions _purgeOptions;
+ private readonly AuditLogOptions _auditOptions;
+ private readonly ILogger _logger;
+ private ICancelable? _timer;
+
+ public AuditLogPurgeActor(
+ IServiceProvider services,
+ IOptions purgeOptions,
+ IOptions auditOptions,
+ ILogger logger)
+ {
+ ArgumentNullException.ThrowIfNull(services);
+ ArgumentNullException.ThrowIfNull(purgeOptions);
+ ArgumentNullException.ThrowIfNull(auditOptions);
+ ArgumentNullException.ThrowIfNull(logger);
+
+ _services = services;
+ _purgeOptions = purgeOptions.Value;
+ _auditOptions = auditOptions.Value;
+ _logger = logger;
+
+ ReceiveAsync(_ => OnTickAsync());
+ }
+
+ protected override void PreStart()
+ {
+ base.PreStart();
+ var interval = _purgeOptions.Interval;
+ _timer = Context.System.Scheduler.ScheduleTellRepeatedlyCancelable(
+ initialDelay: interval,
+ interval: interval,
+ receiver: Self,
+ message: PurgeTick.Instance,
+ sender: Self);
+ }
+
+ protected override void PostStop()
+ {
+ _timer?.Cancel();
+ base.PostStop();
+ }
+
+ ///
+ /// Resume keeps the singleton alive across any leaked exception. Restart
+ /// would re-run PreStart and reschedule the timer (harmless but wasteful);
+ /// Stop is wrong because the singleton must keep ticking until shutdown.
+ ///
+ protected override SupervisorStrategy SupervisorStrategy()
+ {
+ return new OneForOneStrategy(
+ maxNrOfRetries: 0,
+ withinTimeRange: TimeSpan.Zero,
+ decider: Akka.Actor.SupervisorStrategy.DefaultDecider);
+ }
+
+ private async Task OnTickAsync()
+ {
+ // Capture EventStream BEFORE the first await. Accessing Context (and
+ // therefore Context.System) after an await is unsafe because Akka's
+ // ActorBase.Context throws "no active ActorContext" once the
+ // continuation runs on a thread that isn't currently dispatching this
+ // actor — mirrors the same Sender-capture pattern in
+ // AuditLogIngestActor.OnIngestAsync.
+ var eventStream = Context.System.EventStream;
+
+ // Compute the retention threshold from AuditLogOptions.RetentionDays
+ // each tick — the options class supports hot reload via
+ // IOptionsMonitor for the redaction policy and similar settings; we
+ // read the snapshot per-tick so an operator who lowers RetentionDays
+ // sees the change applied on the next purge without an actor
+ // restart.
+ var threshold = DateTime.UtcNow - TimeSpan.FromDays(_auditOptions.RetentionDays);
+
+ IServiceScope? scope = null;
+ IAuditLogRepository repository;
+ try
+ {
+ scope = _services.CreateScope();
+ repository = scope.ServiceProvider.GetRequiredService();
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Failed to resolve IAuditLogRepository for AuditLog purge tick.");
+ scope?.Dispose();
+ return;
+ }
+
+ try
+ {
+ IReadOnlyList boundaries;
+ try
+ {
+ boundaries = await repository
+ .GetPartitionBoundariesOlderThanAsync(threshold)
+ .ConfigureAwait(false);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(
+ ex,
+ "Failed to enumerate eligible AuditLog partition boundaries (threshold {ThresholdUtc:o}); skipping purge tick.",
+ threshold);
+ return;
+ }
+
+ if (boundaries.Count == 0)
+ {
+ return;
+ }
+
+ foreach (var boundary in boundaries)
+ {
+ // Per-boundary try/catch: one bad partition (transient SQL
+ // failure, missing object, contention with backup) does NOT
+ // abandon the rest of the tick.
+ var sw = Stopwatch.StartNew();
+ try
+ {
+ var rowsDeleted = await repository
+ .SwitchOutPartitionAsync(boundary)
+ .ConfigureAwait(false);
+ sw.Stop();
+
+ eventStream.Publish(
+ new AuditLogPurgedEvent(boundary, rowsDeleted, sw.ElapsedMilliseconds));
+
+ _logger.LogInformation(
+ "Purged AuditLog partition {MonthBoundary:yyyy-MM-dd}; {RowsDeleted} rows in {DurationMs} ms.",
+ boundary,
+ rowsDeleted,
+ sw.ElapsedMilliseconds);
+ }
+ catch (Exception ex)
+ {
+ sw.Stop();
+ _logger.LogError(
+ ex,
+ "Failed to purge AuditLog partition {MonthBoundary:yyyy-MM-dd}; other partitions continue. Elapsed {DurationMs} ms.",
+ boundary,
+ sw.ElapsedMilliseconds);
+ }
+ }
+ }
+ finally
+ {
+ scope.Dispose();
+ }
+ }
+
+ /// Self-tick triggering a purge pass across all eligible partitions.
+ internal sealed class PurgeTick
+ {
+ public static readonly PurgeTick Instance = new();
+ private PurgeTick() { }
+ }
+}
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogPurgeOptions.cs b/src/ScadaLink.AuditLog/Central/AuditLogPurgeOptions.cs
new file mode 100644
index 0000000..5f9d824
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditLogPurgeOptions.cs
@@ -0,0 +1,43 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Tuning knobs for the central singleton.
+/// Default cadence is 24 hours per the M6 plan; the retention window itself
+/// is sourced from
+/// (default 365) so operators tune retention from a single section.
+///
+///
+///
+/// The purge actor is a daily-cadence singleton, not a hot-loop, because
+/// partition-switch I/O is metadata-only but the drop-and-rebuild dance
+/// briefly removes the UX_AuditLog_EventId unique index — running
+/// more often than necessary trades index-rebuild outages for marginal
+/// freshness gains. Lower this only when an operator can prove they need
+/// sub-daily purge granularity.
+///
+///
+/// exists for tests to drop the cadence to
+/// milliseconds without polluting the production config surface; production
+/// binds only.
+///
+///
+public sealed class AuditLogPurgeOptions
+{
+ /// Period of the purge tick in hours (default 24).
+ public int IntervalHours { get; set; } = 24;
+
+ ///
+ /// Test-only override for finer control over the tick cadence than
+ /// whole-hour resolution allows. When non-null, takes precedence over
+ /// . Not bound from config — production
+ /// config exposes only.
+ ///
+ public TimeSpan? IntervalOverride { get; set; }
+
+ ///
+ /// Resolves the effective tick interval, honouring the test override
+ /// when set. Falls back to .
+ ///
+ public TimeSpan Interval =>
+ IntervalOverride ?? TimeSpan.FromHours(IntervalHours);
+}
diff --git a/src/ScadaLink.AuditLog/Central/AuditLogPurgedEvent.cs b/src/ScadaLink.AuditLog/Central/AuditLogPurgedEvent.cs
new file mode 100644
index 0000000..78d4987
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/AuditLogPurgedEvent.cs
@@ -0,0 +1,29 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Published on the actor-system EventStream by
+/// after each successful partition switch-out. Downstream consumers (Bundle E
+/// central health collector, ops dashboards, audit trails) subscribe so a
+/// purge action is observable without the actor needing to know about any
+/// specific subscriber.
+///
+///
+/// The pf_AuditLog_Month lower-bound boundary that was switched out — i.e.
+/// the first instant of the purged month in UTC.
+///
+///
+/// Approximate row count purged from the partition, sampled BEFORE the
+/// switch. Exact accounting would require a post-switch scan of the staging
+/// table, which the dance drops immediately, so this is the closest
+/// observable proxy. Zero is a valid value when the actor's enumerator
+/// included a partition the operator subsequently emptied by hand.
+///
+///
+/// Wall-clock time spent inside SwitchOutPartitionAsync for this
+/// boundary, in milliseconds. Useful for spotting the rare slow purge
+/// without spinning up dedicated telemetry.
+///
+public sealed record AuditLogPurgedEvent(
+ DateTime MonthBoundary,
+ long RowsDeleted,
+ long DurationMs);
diff --git a/src/ScadaLink.AuditLog/Central/CentralAuditRedactionFailureCounter.cs b/src/ScadaLink.AuditLog/Central/CentralAuditRedactionFailureCounter.cs
new file mode 100644
index 0000000..102b6d9
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/CentralAuditRedactionFailureCounter.cs
@@ -0,0 +1,57 @@
+using ScadaLink.AuditLog.Payload;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Audit Log (#23) M6 Bundle E (T9) — bridges
+/// (incremented by
+/// every time a header / body / SQL
+/// parameter redactor stage throws and the filter has to over-redact the
+/// offending field) into so the
+/// failure surfaces on the central health surface as
+/// AuditCentralHealthSnapshot.AuditRedactionFailure.
+///
+///
+///
+/// Site vs central. M5 Bundle C wired the SITE-side bridge
+/// (),
+/// which routes increments into the site health report payload's
+/// AuditRedactionFailure field. That handles redactor failures on the
+/// site SQLite hot-path (FallbackAuditWriter). M6 Bundle E (T9) adds the
+/// MIRROR bridge here so the same payload filter — when it runs on the
+/// central /
+/// paths — surfaces its failures on the
+/// central dashboard rather than disappearing into a NoOp.
+///
+///
+/// Registration shape. Site composition roots call
+/// ,
+/// which overrides the binding with the site bridge. Central composition
+/// roots call ,
+/// which overrides with this central bridge. A node never wears both hats —
+/// site and central are distinct host roles — so the two bridges never
+/// fight over the same binding at runtime.
+///
+///
+/// Why not a thin wrapper around the snapshot directly? The snapshot
+/// itself could be the bound implementation (it already implements
+/// ), but a dedicated class makes
+/// the central-vs-site asymmetry explicit at the DI boundary — readers of
+///
+/// see "site → site bridge, central → central bridge", matching the
+///
+/// shape one-for-one.
+///
+///
+public sealed class CentralAuditRedactionFailureCounter : IAuditRedactionFailureCounter
+{
+ private readonly AuditCentralHealthSnapshot _snapshot;
+
+ public CentralAuditRedactionFailureCounter(AuditCentralHealthSnapshot snapshot)
+ {
+ _snapshot = snapshot ?? throw new ArgumentNullException(nameof(snapshot));
+ }
+
+ ///
+ public void Increment() => ((IAuditRedactionFailureCounter)_snapshot).Increment();
+}
diff --git a/src/ScadaLink.AuditLog/Central/CentralAuditWriter.cs b/src/ScadaLink.AuditLog/Central/CentralAuditWriter.cs
index ff48bea..80bfc45 100644
--- a/src/ScadaLink.AuditLog/Central/CentralAuditWriter.cs
+++ b/src/ScadaLink.AuditLog/Central/CentralAuditWriter.cs
@@ -42,6 +42,7 @@ public sealed class CentralAuditWriter : ICentralAuditWriter
private readonly IServiceProvider _services;
private readonly ILogger _logger;
private readonly IAuditPayloadFilter? _filter;
+ private readonly ICentralAuditWriteFailureCounter _failureCounter;
///
/// Bundle C (M5-T6) — the central direct-write path used by the
@@ -50,15 +51,23 @@ public sealed class CentralAuditWriter : ICentralAuditWriter
/// optional so the M4 test composition roots that don't pass one keep
/// working (they only ever write small payloads); production DI registers
/// the real filter via .
+ /// M6 Bundle E (T8) — adds the optional
+ /// so a swallowed repository
+ /// throw bumps the central health surface's
+ /// CentralAuditWriteFailures counter. Defaults to a NoOp so test
+ /// composition roots that don't wire the counter keep their current
+ /// behaviour.
///
public CentralAuditWriter(
IServiceProvider services,
ILogger logger,
- IAuditPayloadFilter? filter = null)
+ IAuditPayloadFilter? filter = null,
+ ICentralAuditWriteFailureCounter? failureCounter = null)
{
_services = services ?? throw new ArgumentNullException(nameof(services));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_filter = filter;
+ _failureCounter = failureCounter ?? new NoOpCentralAuditWriteFailureCounter();
}
///
@@ -92,6 +101,19 @@ public sealed class CentralAuditWriter : ICentralAuditWriter
catch (Exception ex)
{
// Audit failure NEVER aborts the user-facing action — swallow and log.
+ // M6 Bundle E (T8): also surface the failure on the central health
+ // counter so a sustained audit-write outage is visible on the
+ // health dashboard rather than disappearing into the log file.
+ try
+ {
+ _failureCounter.Increment();
+ }
+ catch
+ {
+ // Counter must NEVER throw — defence in depth. Even if a
+ // misbehaving custom counter does, swallowing here keeps the
+ // best-effort contract intact.
+ }
_logger.LogWarning(
ex,
"CentralAuditWriter failed for EventId {EventId} (Kind={Kind}, Status={Status})",
diff --git a/src/ScadaLink.AuditLog/Central/IAuditCentralHealthSnapshot.cs b/src/ScadaLink.AuditLog/Central/IAuditCentralHealthSnapshot.cs
new file mode 100644
index 0000000..6b7fae2
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/IAuditCentralHealthSnapshot.cs
@@ -0,0 +1,62 @@
+using ScadaLink.AuditLog.Payload;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Audit Log (#23) M6 Bundle E read-side surface exposing the central-side
+/// audit-health counters: (every
+/// repository insert throw from /
+/// ),
+/// (every payload-filter redactor throw on the central path), and
+/// (per-site latched state from the
+/// ).
+///
+///
+///
+/// Read-only contract. Implementations expose a point-in-time snapshot
+/// — increments and tracker updates happen through the dedicated counter /
+/// tracker interfaces, not through this surface. Consumers (M7+ central
+/// health pages) read these properties; they never mutate.
+///
+///
+/// Why a parallel surface from .
+/// aggregates per-site
+/// SiteHealthState reports the SITE emits. The central audit-write
+/// failure / redaction-failure counters originate ON central (no site report
+/// carries them), so they live on a dedicated snapshot rather than being
+/// retro-fitted into a per-site state. The two surfaces will be composed at
+/// the M7 dashboard layer.
+///
+///
+public interface IAuditCentralHealthSnapshot
+{
+ ///
+ /// Count of central-side audit-write failures since process start.
+ /// Incremented by every /
+ /// repository insert that throws.
+ ///
+ int CentralAuditWriteFailures { get; }
+
+ ///
+ /// Count of central-side payload-filter redactor over-redactions since
+ /// process start. Incremented by every header / body / SQL-parameter
+ /// redactor stage that throws (the filter falls back to the
+ /// <redacted: redactor error> marker and never aborts the
+ /// user-facing action). Sites have their own counter
+ /// (-backed
+ /// SiteHealthReport.AuditRedactionFailure) and the central
+ /// composition root's binding routes ALL central redactor throws
+ /// (CentralAuditWriter + AuditLogIngestActor paths) into this counter.
+ ///
+ int AuditRedactionFailure { get; }
+
+ ///
+ /// Per-site latched stalled state: true when the
+ /// has observed two
+ /// consecutive non-draining cycles for that site, false after the
+ /// first draining cycle. Sites absent from the map are interpreted as
+ /// healthy (Stalled=false default). Snapshot is a defensive
+ /// copy — readers must not mutate.
+ ///
+ IReadOnlyDictionary SiteAuditTelemetryStalled { get; }
+}
diff --git a/src/ScadaLink.AuditLog/Central/ICentralAuditWriteFailureCounter.cs b/src/ScadaLink.AuditLog/Central/ICentralAuditWriteFailureCounter.cs
new file mode 100644
index 0000000..4e34256
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/ICentralAuditWriteFailureCounter.cs
@@ -0,0 +1,23 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Audit Log (#23) M6 Bundle E (T8) counter sink invoked by central-side audit
+/// writers (, )
+/// every time a repository InsertIfNotExistsAsync throws. Mirrors the
+/// site-side
+/// shape one-for-one — same one-method contract, same NoOp default, same
+/// must-never-abort-the-user-facing-action invariant.
+///
+///
+/// Audit-write failures NEVER abort the user-facing action (alog.md §13) —
+/// the writer swallows the exception and surfaces the failure via this counter
+/// instead. A NoOp default is the correct safe fallback while the central
+/// health surface is being wired in;
+/// is the production binding that routes increments into the aggregated
+/// central health snapshot consumed by future M7+ pages.
+///
+public interface ICentralAuditWriteFailureCounter
+{
+ /// Increment the central audit-write failure counter by one.
+ void Increment();
+}
diff --git a/src/ScadaLink.AuditLog/Central/IPullAuditEventsClient.cs b/src/ScadaLink.AuditLog/Central/IPullAuditEventsClient.cs
new file mode 100644
index 0000000..e094e48
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/IPullAuditEventsClient.cs
@@ -0,0 +1,45 @@
+using ScadaLink.Commons.Messages.Integration;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Mockable abstraction over the central-side PullAuditEvents gRPC
+/// client surface that uses to
+/// fetch the next reconciliation batch from a specific site. Extracted so the
+/// actor can be unit-tested against an in-memory stub without standing up a
+/// real GrpcChannel per site.
+///
+///
+///
+/// The production implementation (host wiring task) wraps the auto-generated
+/// SiteStreamService.SiteStreamServiceClient, multiplexing one
+/// GrpcChannel per site keyed on
+/// . Until that wiring lands the DI
+/// composition root binds a NoOp default that returns an empty response — the
+/// reconciliation tick is still scheduled and the cursor logic still runs, so
+/// regressions in the actor itself are caught even before the real client
+/// arrives.
+///
+///
+/// Implementations MUST NOT throw on transport faults that the actor can
+/// tolerate (connection refused, deadline exceeded). The actor's contract is
+/// "one site's failure doesn't sink the rest of the tick"; an exception still
+/// won't crash the actor (the per-site try/catch catches it), but returning
+/// an empty response on a known-recoverable error keeps the logs cleaner.
+///
+///
+public interface IPullAuditEventsClient
+{
+ ///
+ /// Issues a PullAuditEvents RPC against the site whose endpoint
+ /// is registered against . Returns the next
+ /// batch of
+ /// rows ordered oldest-first AND a MoreAvailable flag the actor
+ /// uses to decide whether to fire another pull immediately.
+ ///
+ Task PullAsync(
+ string siteId,
+ DateTime sinceUtc,
+ int batchSize,
+ CancellationToken ct);
+}
diff --git a/src/ScadaLink.AuditLog/Central/ISiteEnumerator.cs b/src/ScadaLink.AuditLog/Central/ISiteEnumerator.cs
new file mode 100644
index 0000000..9e9607c
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/ISiteEnumerator.cs
@@ -0,0 +1,34 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Enumeration surface consumed by to
+/// discover which sites to poll on each reconciliation tick. Extracted so the
+/// actor can be unit-tested against a static list without depending on the
+/// production ISiteRepository + EF Core DbContext.
+///
+///
+/// The production implementation wraps ISiteRepository.GetAllSitesAsync
+/// and projects each Site to a using the
+/// site's configured GrpcNodeAAddress (falling back to
+/// GrpcNodeBAddress when NodeA is unset). Sites with NO gRPC address
+/// configured are silently skipped — the reconciliation pull cannot reach
+/// them, but absence of an address is a configuration decision, not a runtime
+/// error.
+///
+public interface ISiteEnumerator
+{
+ ///
+ /// Returns the current set of sites the reconciliation puller should visit
+ /// on the next tick. Implementations should reflect adds/removes promptly
+ /// — the actor calls this once per tick.
+ ///
+ Task> EnumerateAsync(CancellationToken ct = default);
+}
+
+///
+/// One reconciliation target: the site identifier the actor uses as the
+/// cursor key and the gRPC endpoint dials
+/// to issue the pull. Endpoint is the bare authority (e.g. http://siteA:8083);
+/// transport selection (TLS, keepalive, etc.) is the client's concern.
+///
+public sealed record SiteEntry(string SiteId, string GrpcEndpoint);
diff --git a/src/ScadaLink.AuditLog/Central/NoOpCentralAuditWriteFailureCounter.cs b/src/ScadaLink.AuditLog/Central/NoOpCentralAuditWriteFailureCounter.cs
new file mode 100644
index 0000000..d4eb216
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/NoOpCentralAuditWriteFailureCounter.cs
@@ -0,0 +1,17 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Default binding used when
+/// the central health surface () has
+/// not been wired (test composition roots, site-only hosts that incidentally
+/// resolve a ). Drops every increment on the
+/// floor. Mirrors .
+///
+public sealed class NoOpCentralAuditWriteFailureCounter : ICentralAuditWriteFailureCounter
+{
+ ///
+ public void Increment()
+ {
+ // intentional no-op
+ }
+}
diff --git a/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationActor.cs b/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationActor.cs
new file mode 100644
index 0000000..e38e6d2
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationActor.cs
@@ -0,0 +1,332 @@
+using Akka.Actor;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Central singleton (M6 Bundle B) that drives the audit-log reconciliation
+/// pull loop. On a configurable timer (default 5 minutes) the actor walks every
+/// known site, asks the site for any rows with
+/// >= the site's last reconciled
+/// cursor, ingests them idempotently into the central
+/// , and advances the cursor.
+///
+///
+///
+/// Self-healing telemetry, not a dispatcher. The push path
+/// ( +
+/// IngestAuditEvents) is the primary mechanism. This actor exists so a
+/// missed push (gRPC blip, central restart, site offline) is eventually
+/// repaired by central re-pulling whatever the site still has in
+/// Pending/Forwarded state. Idempotency on
+/// (M2 Bundle A's race-fix) makes duplicate
+/// arrivals from both paths a silent no-op.
+///
+///
+/// Cursor lifetime. The per-site LastReconciledAt watermark is
+/// kept in-memory for the actor's lifetime. The cluster singleton normally
+/// survives the host process; on a deliberate failover OR a singleton restart
+/// the cursors reset to . That is conservative
+/// but correct — the next tick simply asks for everything the site still has,
+/// and idempotent ingest swallows the dupes. Persisting cursors to MS SQL was
+/// considered and rejected for M6: the cost of a write per tick outweighs the
+/// rare benefit of avoiding one over-broad pull after a restart.
+///
+///
+/// Stalled detection. The brief calls a site "stalled" when two
+/// consecutive pull cycles BOTH return non-empty AND MoreAvailable=true
+/// — i.e. the backlog isn't draining. The actor publishes
+/// on the actor system's
+/// EventStream so a future ICentralHealthCollector bridge (M6 Bundle E)
+/// can flip the health metric without coupling this actor to the health
+/// collection surface today.
+///
+///
+/// Failure isolation. A single site that throws (DNS, transport,
+/// repository write) must NOT prevent other sites from being polled on the
+/// same tick. The per-site work runs inside its own try/catch; the actor's
+/// supervisor strategy keeps it alive across any leaked exception with
+/// 's Restart
+/// semantics — restart resets the in-memory cursors, but as noted above that's
+/// a safe (over-pull, idempotent) recovery.
+///
+///
+/// DI scopes. is a scoped EF Core
+/// service registered by AddConfigurationDatabase. The singleton actor
+/// opens one DI scope per tick and reuses the same repository across all
+/// sites in that tick — one DbContext per tick mirrors the
+/// AuditLogIngestActor + NotificationOutboxActor pattern.
+///
+///
+public class SiteAuditReconciliationActor : ReceiveActor
+{
+ private readonly ISiteEnumerator _sites;
+ private readonly IPullAuditEventsClient _client;
+ private readonly IServiceProvider _services;
+ private readonly SiteAuditReconciliationOptions _options;
+ private readonly ILogger _logger;
+
+ ///
+ /// Per-site reconciliation watermark — the highest
+ /// seen for that site on a previous
+ /// tick. Asking for OccurredAtUtc >= cursor rather than >
+ /// is the site contract ();
+ /// duplicate-with-same-timestamp rows are filtered out by the idempotent
+ /// repository write.
+ ///
+ private readonly Dictionary _cursors = new();
+
+ ///
+ /// Per-site count of consecutive non-draining cycles. Resets to zero on the
+ /// first draining (or empty) cycle.
+ ///
+ private readonly Dictionary _nonDrainingCycles = new();
+
+ ///
+ /// Per-site latched stalled state — used so the actor only publishes a
+ /// transition when the
+ /// stalled flag actually changes, not on every tick while stalled.
+ ///
+ private readonly Dictionary _stalled = new();
+
+ private ICancelable? _timer;
+
+ public SiteAuditReconciliationActor(
+ ISiteEnumerator sites,
+ IPullAuditEventsClient client,
+ IServiceProvider services,
+ IOptions options,
+ ILogger logger)
+ {
+ ArgumentNullException.ThrowIfNull(sites);
+ ArgumentNullException.ThrowIfNull(client);
+ ArgumentNullException.ThrowIfNull(services);
+ ArgumentNullException.ThrowIfNull(options);
+ ArgumentNullException.ThrowIfNull(logger);
+
+ _sites = sites;
+ _client = client;
+ _services = services;
+ _options = options.Value;
+ _logger = logger;
+
+ ReceiveAsync(_ => OnTickAsync());
+ }
+
+ protected override void PreStart()
+ {
+ base.PreStart();
+ var interval = _options.ReconciliationInterval;
+ _timer = Context.System.Scheduler.ScheduleTellRepeatedlyCancelable(
+ initialDelay: interval,
+ interval: interval,
+ receiver: Self,
+ message: ReconciliationTick.Instance,
+ sender: Self);
+ }
+
+ protected override void PostStop()
+ {
+ _timer?.Cancel();
+ base.PostStop();
+ }
+
+ private async Task OnTickAsync()
+ {
+ // Capture EventStream BEFORE the first await. Accessing Context (and
+ // therefore Context.System) after an await is unsafe because Akka's
+ // ActorBase.Context throws "no active ActorContext" once the
+ // continuation runs on a thread that isn't currently dispatching this
+ // actor — mirrors the AuditLogPurgeActor.OnTickAsync fix and the
+ // AuditLogIngestActor.OnIngestAsync Sender-capture pattern.
+ var eventStream = Context.System.EventStream;
+
+ IReadOnlyList sites;
+ try
+ {
+ sites = await _sites.EnumerateAsync().ConfigureAwait(false);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Site enumeration failed; skipping reconciliation tick.");
+ return;
+ }
+
+ if (sites.Count == 0)
+ {
+ return;
+ }
+
+ IServiceScope? scope = null;
+ IAuditLogRepository repository;
+ try
+ {
+ scope = _services.CreateScope();
+ repository = scope.ServiceProvider.GetRequiredService();
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Failed to resolve IAuditLogRepository for reconciliation tick.");
+ scope?.Dispose();
+ return;
+ }
+
+ try
+ {
+ foreach (var site in sites)
+ {
+ try
+ {
+ await PullSiteAsync(site, repository, eventStream).ConfigureAwait(false);
+ }
+ catch (Exception ex)
+ {
+ // Catch-all per the failure-isolation invariant: one site's
+ // fault must not sink the rest of the tick. The cursor for
+ // the failing site is left at its previous value so the
+ // next tick retries the same window.
+ _logger.LogWarning(
+ ex,
+ "Reconciliation pull failed for site {SiteId}; other sites continue.",
+ site.SiteId);
+ }
+ }
+ }
+ finally
+ {
+ scope.Dispose();
+ }
+ }
+
+ ///
+ /// Issues one PullAuditEvents RPC against the site, ingests the
+ /// returned rows idempotently into the central repository, and advances
+ /// the cursor based on the maximum
+ /// observed. The brief's "saturate until backlog clears" intent is met by
+ /// the natural cadence — each tick issues one pull, and a backed-up site
+ /// drains across consecutive ticks. The stalled signal (two non-draining
+ /// ticks in a row) surfaces when that drain isn't keeping up.
+ ///
+ private async Task PullSiteAsync(SiteEntry site, IAuditLogRepository repository, Akka.Event.EventStream eventStream)
+ {
+ var since = _cursors.TryGetValue(site.SiteId, out var c) ? c : DateTime.MinValue;
+ var response = await _client.PullAsync(
+ site.SiteId, since, _options.BatchSize, CancellationToken.None)
+ .ConfigureAwait(false);
+
+ var maxOccurred = since;
+ var nowUtc = DateTime.UtcNow;
+ foreach (var evt in response.Events)
+ {
+ try
+ {
+ // Idempotent repository write: duplicate EventIds (from a
+ // concurrent push, or a retry of this very pull) collapse to
+ // a no-op courtesy of M2 Bundle A's race-fix on
+ // InsertIfNotExistsAsync.
+ var ingested = evt with { IngestedAtUtc = nowUtc };
+ await repository.InsertIfNotExistsAsync(ingested).ConfigureAwait(false);
+ }
+ catch (Exception ex)
+ {
+ // Per-row catch so one bad event does not abandon the rest of
+ // the batch. The cursor still advances based on OccurredAtUtc
+ // — the row was returned by the site, so the next tick won't
+ // re-fetch it; if it permanently fails to persist, that's an
+ // operational concern surfaced by the log, not a hot-loop
+ // trigger.
+ _logger.LogError(
+ ex,
+ "Reconciliation ingest failed for AuditEvent {EventId} from site {SiteId}.",
+ evt.EventId,
+ site.SiteId);
+ }
+
+ if (evt.OccurredAtUtc > maxOccurred)
+ {
+ maxOccurred = evt.OccurredAtUtc;
+ }
+ }
+
+ _cursors[site.SiteId] = maxOccurred;
+
+ var nonDraining = response.MoreAvailable && response.Events.Count > 0;
+ UpdateStalledState(site.SiteId, draining: !nonDraining, eventStream);
+ }
+
+ ///
+ /// Flips the per-site stalled flag based on whether this tick drained the
+ /// queue. A "draining" cycle is one where the server reported no more rows
+ /// available OR returned zero events. A "non-draining" cycle is the
+ /// inverse (events returned AND MoreAvailable=true).
+ ///
+ ///
+ /// The state machine: counter increments on each consecutive non-draining
+ /// tick. On reaching
+ /// the actor latches Stalled=true and publishes the transition; on
+ /// any subsequent draining tick the counter resets to zero AND, if the
+ /// latch is currently true, the actor publishes Stalled=false. Only
+ /// transitions are published — repeated ticks in the same state are
+ /// silent so a downstream subscriber doesn't see a flood of redundant
+ /// notifications.
+ ///
+ private void UpdateStalledState(string siteId, bool draining, Akka.Event.EventStream eventStream)
+ {
+ var wasStalled = _stalled.TryGetValue(siteId, out var prior) && prior;
+
+ if (draining)
+ {
+ _nonDrainingCycles[siteId] = 0;
+ if (wasStalled)
+ {
+ _stalled[siteId] = false;
+ eventStream.Publish(
+ new SiteAuditTelemetryStalledChanged(siteId, Stalled: false));
+ }
+ return;
+ }
+
+ var consecutive = _nonDrainingCycles.GetValueOrDefault(siteId) + 1;
+ _nonDrainingCycles[siteId] = consecutive;
+
+ if (consecutive >= _options.StalledAfterNonDrainingCycles && !wasStalled)
+ {
+ _stalled[siteId] = true;
+ eventStream.Publish(
+ new SiteAuditTelemetryStalledChanged(siteId, Stalled: true));
+ }
+ }
+
+ ///
+ /// Resume on any unhandled exception inside the receive — the singleton
+ /// MUST stay alive even if the per-tick try/catch leaks. Restart would
+ /// reset the cursors (safe but wasteful); Resume preserves them.
+ ///
+ protected override SupervisorStrategy SupervisorStrategy()
+ {
+ return new OneForOneStrategy(
+ maxNrOfRetries: 0,
+ withinTimeRange: TimeSpan.Zero,
+ decider: Akka.Actor.SupervisorStrategy.DefaultDecider);
+ }
+
+ /// Self-tick triggering a reconciliation pass across all sites.
+ internal sealed class ReconciliationTick
+ {
+ public static readonly ReconciliationTick Instance = new();
+ private ReconciliationTick() { }
+ }
+}
+
+///
+/// Published on the actor system EventStream when a site's reconciliation
+/// puller transitions into or out of the "stalled" state (backlog not
+/// draining across multiple cycles). The M6 Bundle E central health collector
+/// will subscribe to this and surface
+/// SiteAuditTelemetryStalled on the health-report payload.
+///
+public sealed record SiteAuditTelemetryStalledChanged(string SiteId, bool Stalled);
diff --git a/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationOptions.cs b/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationOptions.cs
new file mode 100644
index 0000000..d32c5e6
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/SiteAuditReconciliationOptions.cs
@@ -0,0 +1,60 @@
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Tuning knobs for the central singleton.
+/// Defaults mirror the M6 Bundle B brief: pull every 5 minutes per site, 256 rows per
+/// batch, declare a site "stalled" after two consecutive pull cycles return non-empty
+/// AND MoreAvailable=true (the backlog is not draining).
+///
+///
+///
+/// Per the M6 plan the reconciliation actor is the fallback when push telemetry is
+/// lost; it is intentionally low-frequency. Lowering
+/// in production trades MS SQL load for
+/// fresher self-healing — keep the default unless a deployment can prove the extra
+/// load is acceptable.
+///
+///
+/// = 2 because a single non-draining
+/// cycle can happen on a surge (e.g. a backed-up site replays its hot queue); the
+/// stalled signal should only fire when the backlog persists across cycles, which is
+/// the symptom the central health surface is asking us to detect.
+///
+///
+public sealed class SiteAuditReconciliationOptions
+{
+ ///
+ /// Period of the reconciliation tick. Each tick visits every known site once.
+ ///
+ public int ReconciliationIntervalSeconds { get; set; } = 300;
+
+ ///
+ /// Test-only override for finer control over the tick cadence than
+ /// whole-second resolution allows. When non-null, takes precedence over
+ /// . Not bound from config —
+ /// production config exposes
+ /// only.
+ ///
+ public TimeSpan? ReconciliationIntervalOverride { get; set; }
+
+ ///
+ /// Resolves the effective tick interval, honouring the test override when
+ /// set. Falls back to .
+ ///
+ public TimeSpan ReconciliationInterval =>
+ ReconciliationIntervalOverride ?? TimeSpan.FromSeconds(ReconciliationIntervalSeconds);
+
+ ///
+ /// Maximum number of
+ /// rows requested in a single PullAuditEvents RPC call.
+ ///
+ public int BatchSize { get; set; } = 256;
+
+ ///
+ /// Number of consecutive non-draining cycles (events returned AND
+ /// MoreAvailable=true) that must accumulate for a site before the actor
+ /// publishes SiteAuditTelemetryStalledChanged(Stalled: true) on the
+ /// EventStream.
+ ///
+ public int StalledAfterNonDrainingCycles { get; set; } = 2;
+}
diff --git a/src/ScadaLink.AuditLog/Central/SiteAuditTelemetryStalledTracker.cs b/src/ScadaLink.AuditLog/Central/SiteAuditTelemetryStalledTracker.cs
new file mode 100644
index 0000000..e1ed0fd
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Central/SiteAuditTelemetryStalledTracker.cs
@@ -0,0 +1,188 @@
+using System.Collections.Concurrent;
+using Akka.Actor;
+using Akka.Event;
+
+namespace ScadaLink.AuditLog.Central;
+
+///
+/// Audit Log (#23) M6 Bundle E (T7) — central singleton that subscribes to the
+/// actor system's EventStream for
+/// publications and maintains a per-site latched stalled-state map readable
+/// via . Consumed by the M6 Bundle E
+/// aggregator so the central health
+/// surface can surface per-site "reconciliation isn't draining" without
+/// coupling the publisher () to the
+/// health collection plumbing.
+///
+///
+///
+/// Why an internal actor. Akka.NET's only
+/// supports subscribers — there is no callback or
+/// channel-based overload. The tracker therefore spawns a small subscriber
+/// actor that forwards each event into the shared
+/// on the actor's thread, and
+/// readers () take a copy off that dictionary on any
+/// thread. Mirrors the DeadLetterMonitorActor shape — subscribe in
+/// , unsubscribe in
+/// , which the tracker triggers via a Stop
+/// at .
+///
+///
+/// Per-site latching. The publisher ()
+/// only publishes on stalled-state transitions, so the dictionary is the
+/// authoritative latched state. Sites that have never published are absent
+/// from the snapshot — the consumer surface treats absence as
+/// Stalled=false (default healthy), the same default the reconciliation
+/// actor's own internal latch uses.
+///
+///
+/// Singleton lifecycle. Registered as a singleton via
+/// ;
+/// tears the internal subscriber down at host shutdown.
+///
+///
+public sealed class SiteAuditTelemetryStalledTracker : IDisposable
+{
+ private readonly EventStream _eventStream;
+ private readonly ConcurrentDictionary _state = new();
+ private readonly IActorRef? _subscriber;
+ private readonly AuditCentralHealthSnapshot? _snapshot;
+ private bool _disposed;
+
+ ///
+ /// Construct around a bare . Intended for unit
+ /// tests where the caller wants to publish events without standing up an
+ /// actor system — the tracker registers a transient subscriber actor only
+ /// if the supplied stream is backed by an actor system. In the bare-stream
+ /// mode (no actor system) the tracker still exposes the
+ /// surface but cannot self-subscribe; production
+ /// callers always go through .
+ ///
+ ///
+ /// Subscribing to requires an ,
+ /// which can only be created from an . The bare-
+ /// stream ctor therefore can NOT itself wire the subscriber — tests that
+ /// want event-driven updates must use the ActorSystem ctor (or push state
+ /// directly via ). The tests in
+ /// SiteAuditTelemetryStalledTrackerTests use the ActorSystem ctor
+ /// via Akka.TestKit so they exercise the production subscribe path.
+ ///
+ public SiteAuditTelemetryStalledTracker(EventStream eventStream)
+ : this(eventStream, snapshot: null)
+ {
+ }
+
+ ///
+ /// Bare-stream ctor with an optional snapshot sink — the central
+ /// composition root passes the singleton
+ /// so every dictionary update
+ /// also lands on the central health surface. The bare ctor still cannot
+ /// subscribe (no actor system), but tests that drive the tracker via
+ /// get the snapshot push for free.
+ ///
+ public SiteAuditTelemetryStalledTracker(EventStream eventStream, AuditCentralHealthSnapshot? snapshot)
+ {
+ _eventStream = eventStream ?? throw new ArgumentNullException(nameof(eventStream));
+ // No subscriber actor — see the remarks on the parameterless overload.
+ _subscriber = null;
+ _snapshot = snapshot;
+ }
+
+ ///
+ /// Production ctor: subscribes a small internal actor to the supplied
+ /// system's EventStream so every published
+ /// updates the latched
+ /// per-site map. tears the subscriber down.
+ ///
+ public SiteAuditTelemetryStalledTracker(ActorSystem actorSystem)
+ : this(actorSystem, snapshot: null)
+ {
+ }
+
+ ///
+ /// Production ctor with a snapshot sink — every observed
+ /// is mirrored onto the
+ /// shared so the central health
+ /// surface sees per-site stalled state without re-reading the tracker.
+ ///
+ public SiteAuditTelemetryStalledTracker(ActorSystem actorSystem, AuditCentralHealthSnapshot? snapshot)
+ {
+ ArgumentNullException.ThrowIfNull(actorSystem);
+ _eventStream = actorSystem.EventStream;
+ _snapshot = snapshot;
+ // Anonymous subscriber actor scoped to the system; props build it
+ // with a callback into THIS tracker's Apply method so the actor's
+ // single-threaded receive serialises every dictionary write.
+ _subscriber = actorSystem.ActorOf(
+ Props.Create(() => new StalledChangedSubscriber(this)),
+ name: $"site-audit-stalled-tracker-{Guid.NewGuid():N}");
+ // Subscribe synchronously from the ctor so the subscription is in
+ // place before the tracker is returned to the caller — the actor's
+ // own PreStart runs asynchronously and would otherwise race the
+ // first publish. EventStream.Subscribe is thread-safe.
+ _eventStream.Subscribe(_subscriber, typeof(SiteAuditTelemetryStalledChanged));
+ }
+
+ ///
+ /// Returns a defensive copy of the per-site latched stalled state.
+ /// Absent sites are interpreted as Stalled=false by consumers.
+ ///
+ public IReadOnlyDictionary Snapshot() =>
+ new Dictionary(_state);
+
+ ///
+ /// Applied by the internal subscriber actor on every
+ /// publication. Exposed
+ /// internally so tests against the bare-stream ctor can still drive the
+ /// tracker, but the production path always goes through the actor.
+ ///
+ internal void Apply(SiteAuditTelemetryStalledChanged evt)
+ {
+ if (evt is null) return;
+ _state[evt.SiteId] = evt.Stalled;
+ // Mirror into the central health snapshot if wired so a reader of
+ // IAuditCentralHealthSnapshot sees the same per-site state without
+ // a second lookup. Snapshot is optional (test composition roots may
+ // skip it) so the null-coalesce is the safe path.
+ _snapshot?.ApplyStalled(evt);
+ }
+
+ public void Dispose()
+ {
+ if (_disposed) return;
+ _disposed = true;
+ if (_subscriber is not null)
+ {
+ // Unsubscribe runs in PostStop on the subscriber actor; Stop is
+ // fire-and-forget but the actor's PostStop hook is guaranteed to
+ // run before its mailbox is collected.
+ _subscriber.Tell(PoisonPill.Instance);
+ }
+ }
+
+ ///
+ /// Internal subscriber actor — receives every
+ /// off the EventStream and
+ /// forwards it into the parent .
+ /// Unlike DeadLetterMonitorActor, the subscription is registered by
+ /// the tracker constructor BEFORE this actor begins processing messages so
+ /// publishes that arrive between actor creation and PreStart cannot be
+ /// missed. Unsubscribe still runs in .
+ ///
+ private sealed class StalledChangedSubscriber : ReceiveActor
+ {
+ private readonly SiteAuditTelemetryStalledTracker _parent;
+
+ public StalledChangedSubscriber(SiteAuditTelemetryStalledTracker parent)
+ {
+ _parent = parent;
+ Receive(evt => _parent.Apply(evt));
+ }
+
+ protected override void PostStop()
+ {
+ Context.System.EventStream.Unsubscribe(Self, typeof(SiteAuditTelemetryStalledChanged));
+ base.PostStop();
+ }
+ }
+}
diff --git a/src/ScadaLink.AuditLog/ServiceCollectionExtensions.cs b/src/ScadaLink.AuditLog/ServiceCollectionExtensions.cs
index cf04abd..626859f 100644
--- a/src/ScadaLink.AuditLog/ServiceCollectionExtensions.cs
+++ b/src/ScadaLink.AuditLog/ServiceCollectionExtensions.cs
@@ -1,6 +1,7 @@
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ScadaLink.AuditLog.Central;
@@ -43,6 +44,9 @@ public static class ServiceCollectionExtensions
/// Configuration section bound to .
public const string SiteTelemetrySectionName = "AuditLog:SiteTelemetry";
+ /// Configuration section bound to .
+ public const string PartitionMaintenanceSectionName = "AuditLog:PartitionMaintenance";
+
///
/// Registers the Audit Log (#23) component services: options, the site
/// SQLite writer chain (primary + ring fallback + failure-counter sink),
@@ -151,6 +155,13 @@ public static class ServiceCollectionExtensions
services.AddSingleton(
sp => sp.GetRequiredService());
+ // M6 Bundle E (T8): central audit-write failure counter — NoOp default
+ // for site/test composition roots that don't wire the central health
+ // snapshot. AddAuditLogCentralMaintenance below replaces this binding
+ // with the AuditCentralHealthSnapshot implementation so increments
+ // surface on the central dashboard.
+ services.TryAddSingleton();
+
// M4 Bundle B: central direct-write audit writer used by
// NotificationOutboxActor (Bundle B) and Inbound API (Bundle C/D) to
// emit AuditLog rows that originate ON central, not via site telemetry.
@@ -163,10 +174,13 @@ public static class ServiceCollectionExtensions
// Bundle C (M5-T6): wire the IAuditPayloadFilter into the factory so
// NotificationOutboxActor + Inbound API rows are truncated + redacted
// before they hit MS SQL.
+ // M6 Bundle E (T8): also wire the ICentralAuditWriteFailureCounter
+ // so swallowed repo throws bump the central health counter.
services.AddSingleton(sp => new CentralAuditWriter(
sp,
sp.GetRequiredService>(),
- sp.GetRequiredService()));
+ sp.GetRequiredService(),
+ sp.GetRequiredService()));
return services;
}
@@ -214,6 +228,80 @@ public static class ServiceCollectionExtensions
ServiceDescriptor.Singleton());
services.Replace(
ServiceDescriptor.Singleton());
+ // M6 Bundle E (T6): the site-side backlog reporter polls the
+ // SqliteAuditWriter every 30 s and pushes the snapshot into the
+ // collector so the next SiteHealthReport carries a fresh
+ // SiteAuditBacklog field. Registered alongside the other site-only
+ // metric bridges so AddAuditLog (which runs on central too) stays
+ // free of hosted-service registrations that would resolve a missing
+ // ISiteHealthCollector on central.
+ services.AddHostedService();
+ return services;
+ }
+
+ ///
+ /// Audit Log (#23) M6-T5 Bundle D — central-only registration for the
+ /// hosted service plus
+ /// its binding. Must be
+ /// called from the Central role's composition root (not from a site
+ /// composition root); the underlying IPartitionMaintenance
+ /// implementation is registered by AddConfigurationDatabase and
+ /// only exists on the central node.
+ ///
+ ///
+ ///
+ /// Separated from because AddAuditLog is
+ /// also invoked from site composition roots — silently starting a
+ /// hosted service that resolves an unregistered dependency on a site
+ /// would fail every tick. Keeping the central-only registration in its
+ /// own helper preserves the "every Add* call is safe to issue
+ /// from any composition root" invariant.
+ ///
+ ///
+ public static IServiceCollection AddAuditLogCentralMaintenance(
+ this IServiceCollection services,
+ IConfiguration config)
+ {
+ ArgumentNullException.ThrowIfNull(services);
+ ArgumentNullException.ThrowIfNull(config);
+
+ services.AddOptions()
+ .Bind(config.GetSection(PartitionMaintenanceSectionName));
+ services.AddHostedService();
+
+ // M6 Bundle E (T8 + T9): central health snapshot — a single object
+ // that owns the CentralAuditWriteFailures + AuditRedactionFailure
+ // Interlocked counters AND surfaces them on
+ // IAuditCentralHealthSnapshot. The same instance is bound to BOTH
+ // writer-side interfaces (ICentralAuditWriteFailureCounter +
+ // IAuditRedactionFailureCounter) so every central-side increment
+ // routes into the shared counters; site nodes keep their existing
+ // Site bridges (registered by AddAuditLogHealthMetricsBridge) so
+ // the same counter type does not shadow the site-side metric.
+ // The snapshot itself has no actor-system dependency — the
+ // per-site stalled latch is fed by SiteAuditTelemetryStalledTracker
+ // which the Akka bootstrap wires up after ActorSystem.Create returns
+ // (the tracker is NOT registered here because its construction
+ // requires ActorSystem, which is not a DI-resolvable singleton).
+ services.AddSingleton();
+ services.AddSingleton(
+ sp => sp.GetRequiredService());
+ services.Replace(ServiceDescriptor.Singleton(
+ sp => sp.GetRequiredService()));
+ // M6 Bundle E (T9): override the NoOp IAuditRedactionFailureCounter
+ // (registered by AddAuditLog) with the CentralAuditRedactionFailureCounter
+ // bridge so payload-filter throws on CentralAuditWriter /
+ // AuditLogIngestActor paths surface on the central dashboard. The
+ // bridge is a thin wrapper around the AuditCentralHealthSnapshot
+ // singleton so all central redactor failures route into the same
+ // counter as CentralAuditWriteFailures. The site composition root
+ // overrides this binding AGAIN via AddAuditLogHealthMetricsBridge —
+ // central nodes do not call that bridge, so this is the final
+ // binding on a central host. Mirrors the M5 Bundle C
+ // HealthMetricsAuditRedactionFailureCounter shape one-for-one.
+ services.Replace(ServiceDescriptor.Singleton());
+
return services;
}
}
diff --git a/src/ScadaLink.AuditLog/Site/SiteAuditBacklogReporter.cs b/src/ScadaLink.AuditLog/Site/SiteAuditBacklogReporter.cs
new file mode 100644
index 0000000..955832a
--- /dev/null
+++ b/src/ScadaLink.AuditLog/Site/SiteAuditBacklogReporter.cs
@@ -0,0 +1,133 @@
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using ScadaLink.Commons.Interfaces.Services;
+using ScadaLink.HealthMonitoring;
+
+namespace ScadaLink.AuditLog.Site;
+
+///
+/// Audit Log (#23) M6 Bundle E (T6) — site-side hosted service that
+/// periodically pulls a backlog snapshot from
+/// and pushes it into so the next
+/// emits a fresh
+/// SiteAuditBacklog field on the site health report.
+///
+///
+///
+/// Why a hosted service, not the report sender. Querying SQLite for the
+/// backlog requires the queue's write lock; doing it inline in
+/// would couple the collector
+/// to and turn an in-memory snapshot read into
+/// a synchronous I/O call on the report path. The hosted-service pattern keeps
+/// the report path pure and the SQL probe off the report timing budget.
+///
+///
+/// Cadence. 30 s by default — coarse enough to amortise the SQL probe
+/// across many reports, fine enough that the central dashboard never lags by
+/// more than one health-report interval. Tunable via
+/// in a follow-up
+/// if ops needs a different cadence; for M6 we hard-code the value because the
+/// brief calls it out explicitly.
+///
+///
+/// Failure containment. The probe call is wrapped in a try/catch so a
+/// transient SQLite error never tears down the hosted service — the next tick
+/// retries. Mirrors 's
+/// "exception logged, not propagated" contract.
+///
+///
+public sealed class SiteAuditBacklogReporter : IHostedService, IDisposable
+{
+ ///
+ /// Default poll cadence. Half a typical 60 s health-report interval keeps
+ /// the snapshot fresh without spinning the SQL probe more often than
+ /// necessary.
+ ///
+ internal static readonly TimeSpan DefaultRefreshInterval = TimeSpan.FromSeconds(30);
+
+ private readonly ISiteAuditQueue _queue;
+ private readonly ISiteHealthCollector _collector;
+ private readonly ILogger _logger;
+ private readonly TimeSpan _refreshInterval;
+ private CancellationTokenSource? _cts;
+ private Task? _loop;
+
+ public SiteAuditBacklogReporter(
+ ISiteAuditQueue queue,
+ ISiteHealthCollector collector,
+ ILogger logger,
+ TimeSpan? refreshInterval = null)
+ {
+ _queue = queue ?? throw new ArgumentNullException(nameof(queue));
+ _collector = collector ?? throw new ArgumentNullException(nameof(collector));
+ _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+ _refreshInterval = refreshInterval ?? DefaultRefreshInterval;
+ }
+
+ ///
+ public Task StartAsync(CancellationToken ct)
+ {
+ // Linked CTS lets StopAsync's cancellation AND the host's shutdown
+ // token both terminate the loop; either side firing aborts the
+ // pending Task.Delay.
+ _cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+ _loop = Task.Run(() => RunLoopAsync(_cts.Token));
+ return Task.CompletedTask;
+ }
+
+ private async Task RunLoopAsync(CancellationToken ct)
+ {
+ // First tick runs immediately so the very first health report after
+ // process start carries a real backlog snapshot — without this the
+ // dashboard would show null for the first 30 s after a deploy.
+ await SafeProbeAsync(ct).ConfigureAwait(false);
+
+ while (!ct.IsCancellationRequested)
+ {
+ try
+ {
+ await Task.Delay(_refreshInterval, ct).ConfigureAwait(false);
+ }
+ catch (OperationCanceledException)
+ {
+ break;
+ }
+
+ await SafeProbeAsync(ct).ConfigureAwait(false);
+ }
+ }
+
+ private async Task SafeProbeAsync(CancellationToken ct)
+ {
+ try
+ {
+ var snapshot = await _queue.GetBacklogStatsAsync(ct).ConfigureAwait(false);
+ _collector.UpdateSiteAuditBacklog(snapshot);
+ }
+ catch (OperationCanceledException)
+ {
+ // Shutdown — let the outer loop exit cleanly.
+ throw;
+ }
+ catch (Exception ex)
+ {
+ // Catch-all is deliberate: the hosted service must survive every
+ // class of probe failure (transient SQLite lock contention, disk
+ // I/O hiccup, …) so the next tick gets a chance.
+ _logger.LogWarning(ex, "SiteAuditBacklogReporter probe failed; next tick will retry.");
+ }
+ }
+
+ ///
+ public Task StopAsync(CancellationToken ct)
+ {
+ _cts?.Cancel();
+ return _loop ?? Task.CompletedTask;
+ }
+
+ ///
+ public void Dispose()
+ {
+ _cts?.Dispose();
+ }
+}
diff --git a/src/ScadaLink.AuditLog/Site/SqliteAuditWriter.cs b/src/ScadaLink.AuditLog/Site/SqliteAuditWriter.cs
index 789b572..bf5cb8b 100644
--- a/src/ScadaLink.AuditLog/Site/SqliteAuditWriter.cs
+++ b/src/ScadaLink.AuditLog/Site/SqliteAuditWriter.cs
@@ -2,9 +2,9 @@ using System.Threading.Channels;
using Microsoft.Data.Sqlite;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
-using ScadaLink.AuditLog.Site.Telemetry;
using ScadaLink.Commons.Entities.Audit;
using ScadaLink.Commons.Interfaces.Services;
+using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
namespace ScadaLink.AuditLog.Site;
@@ -390,6 +390,184 @@ public class SqliteAuditWriter : IAuditWriter, ISiteAuditQueue, IAsyncDisposable
}
}
+ ///
+ /// M6 reconciliation-pull read: returns up to rows
+ /// whose OccurredAtUtc >= sinceUtc and whose
+ /// is still or
+ /// . Forwarded rows are included so the
+ /// brief race window between a site-Forwarded ack and central ingest cannot
+ /// silently drop rows; central dedups on .
+ /// Ordered oldest first, EventId tiebreaker.
+ ///
+ public Task> ReadPendingSinceAsync(
+ DateTime sinceUtc, int batchSize, CancellationToken ct = default)
+ {
+ if (batchSize <= 0)
+ {
+ throw new ArgumentOutOfRangeException(nameof(batchSize), "batchSize must be > 0.");
+ }
+
+ // Mirror ReadPendingAsync: the write lock guards the single connection.
+ lock (_writeLock)
+ {
+ ObjectDisposedException.ThrowIf(_disposed, this);
+
+ using var cmd = _connection.CreateCommand();
+ cmd.CommandText = """
+ SELECT EventId, OccurredAtUtc, Channel, Kind, CorrelationId,
+ SourceSiteId, SourceInstanceId, SourceScript, Actor, Target,
+ Status, HttpStatus, DurationMs, ErrorMessage, ErrorDetail,
+ RequestSummary, ResponseSummary, PayloadTruncated, Extra, ForwardState
+ FROM AuditLog
+ WHERE ForwardState IN ($pending, $forwarded)
+ AND OccurredAtUtc >= $since
+ ORDER BY OccurredAtUtc ASC, EventId ASC
+ LIMIT $limit;
+ """;
+ cmd.Parameters.AddWithValue("$pending", AuditForwardState.Pending.ToString());
+ cmd.Parameters.AddWithValue("$forwarded", AuditForwardState.Forwarded.ToString());
+ // Normalise to UTC ISO-8601 round-trip format to match how OccurredAtUtc
+ // is stored on insert ("o" format) — string comparison is monotonic for
+ // that encoding so we can index-scan against it.
+ cmd.Parameters.AddWithValue("$since", EnsureUtc(sinceUtc).ToString(
+ "o", System.Globalization.CultureInfo.InvariantCulture));
+ cmd.Parameters.AddWithValue("$limit", batchSize);
+
+ var rows = new List(Math.Min(batchSize, 256));
+ using var reader = cmd.ExecuteReader();
+ while (reader.Read())
+ {
+ rows.Add(MapRow(reader));
+ }
+
+ return Task.FromResult>(rows);
+ }
+ }
+
+ ///
+ /// M6 reconciliation-pull commit: flips the supplied EventIds to
+ /// , but ONLY for rows currently in
+ /// or .
+ /// Rows already in are left untouched
+ /// (idempotent re-call). Non-existent ids are silent no-ops.
+ ///
+ public Task MarkReconciledAsync(IReadOnlyList eventIds, CancellationToken ct = default)
+ {
+ ArgumentNullException.ThrowIfNull(eventIds);
+ if (eventIds.Count == 0)
+ {
+ return Task.CompletedTask;
+ }
+
+ lock (_writeLock)
+ {
+ ObjectDisposedException.ThrowIf(_disposed, this);
+
+ using var cmd = _connection.CreateCommand();
+ var sb = new System.Text.StringBuilder();
+ sb.Append("UPDATE AuditLog SET ForwardState = $reconciled ")
+ .Append("WHERE ForwardState IN ($pending, $forwarded) AND EventId IN (");
+ for (int i = 0; i < eventIds.Count; i++)
+ {
+ if (i > 0) sb.Append(',');
+ var p = $"$id{i}";
+ sb.Append(p);
+ cmd.Parameters.AddWithValue(p, eventIds[i].ToString());
+ }
+ sb.Append(");");
+ cmd.CommandText = sb.ToString();
+ cmd.Parameters.AddWithValue("$reconciled", AuditForwardState.Reconciled.ToString());
+ cmd.Parameters.AddWithValue("$pending", AuditForwardState.Pending.ToString());
+ cmd.Parameters.AddWithValue("$forwarded", AuditForwardState.Forwarded.ToString());
+
+ cmd.ExecuteNonQuery();
+ return Task.CompletedTask;
+ }
+ }
+
+ ///
+ /// M6 Bundle E (T6) health-metric surface: returns a point-in-time snapshot
+ /// of the site queue's pending count, the oldest pending row's
+ /// , and the on-disk file size. Called
+ /// by the site-side SiteAuditBacklogReporter hosted service on its
+ /// 30 s tick to refresh the SiteHealthReport.SiteAuditBacklog field.
+ ///
+ ///
+ /// The pending-count + oldest-row queries run inside the same write lock as
+ /// the hot-path INSERT batch so the snapshot is consistent against the
+ /// connection's view (no torn read of an in-flight transaction). The on-disk
+ /// size lookup happens OUTSIDE the lock — it's a stat() call on the file
+ /// path and doesn't touch the connection. In-memory and missing files
+ /// return 0 bytes (the snapshot is for ops dashboards, not a correctness
+ /// invariant).
+ ///
+ public Task GetBacklogStatsAsync(CancellationToken ct = default)
+ {
+ int pendingCount;
+ DateTime? oldestPending;
+
+ lock (_writeLock)
+ {
+ ObjectDisposedException.ThrowIf(_disposed, this);
+
+ // Single round-trip — COUNT(*) + MIN(OccurredAtUtc) over the same
+ // index range avoids a second scan. The IX_SiteAuditLog_ForwardState_Occurred
+ // index makes both aggregates cheap (count is a covering scan, min
+ // is the first key).
+ using var cmd = _connection.CreateCommand();
+ cmd.CommandText = """
+ SELECT COUNT(*), MIN(OccurredAtUtc)
+ FROM AuditLog
+ WHERE ForwardState = $pending;
+ """;
+ cmd.Parameters.AddWithValue("$pending", AuditForwardState.Pending.ToString());
+
+ using var reader = cmd.ExecuteReader();
+ reader.Read();
+ pendingCount = reader.GetInt32(0);
+ oldestPending = reader.IsDBNull(1)
+ ? null
+ : DateTime.Parse(reader.GetString(1),
+ System.Globalization.CultureInfo.InvariantCulture,
+ System.Globalization.DateTimeStyles.RoundtripKind);
+ }
+
+ // File-size lookup outside the lock — the DatabasePath option is the
+ // canonical source. The connection-string-override branch (used by
+ // some tests) keeps the same DatabasePath value, so this works
+ // uniformly. In-memory / mode=memory paths return 0 because the file
+ // doesn't exist on disk.
+ long onDiskBytes = 0;
+ try
+ {
+ if (!string.IsNullOrEmpty(_options.DatabasePath) &&
+ !_options.DatabasePath.StartsWith(":memory:", StringComparison.Ordinal) &&
+ !_options.DatabasePath.Contains("mode=memory", StringComparison.OrdinalIgnoreCase) &&
+ File.Exists(_options.DatabasePath))
+ {
+ onDiskBytes = new FileInfo(_options.DatabasePath).Length;
+ }
+ }
+ catch (Exception ex)
+ {
+ // File system probe is a best-effort health-metric — never abort
+ // a backlog snapshot because stat() failed. Log and report 0.
+ _logger.LogDebug(ex,
+ "SqliteAuditWriter could not stat DB path {Path} for backlog snapshot.",
+ _options.DatabasePath);
+ }
+
+ return Task.FromResult(new SiteAuditBacklogSnapshot(
+ PendingCount: pendingCount,
+ OldestPendingUtc: oldestPending,
+ OnDiskBytes: onDiskBytes));
+ }
+
+ private static DateTime EnsureUtc(DateTime value) =>
+ value.Kind == DateTimeKind.Utc
+ ? value
+ : DateTime.SpecifyKind(value.ToUniversalTime(), DateTimeKind.Utc);
+
private static AuditEvent MapRow(SqliteDataReader reader)
{
return new AuditEvent
diff --git a/src/ScadaLink.AuditLog/Site/Telemetry/ISiteAuditQueue.cs b/src/ScadaLink.AuditLog/Site/Telemetry/ISiteAuditQueue.cs
deleted file mode 100644
index 9da55b5..0000000
--- a/src/ScadaLink.AuditLog/Site/Telemetry/ISiteAuditQueue.cs
+++ /dev/null
@@ -1,34 +0,0 @@
-using ScadaLink.Commons.Entities.Audit;
-
-namespace ScadaLink.AuditLog.Site.Telemetry;
-
-///
-/// Site-local audit-log queue surface consumed by .
-/// Extracted from so the telemetry actor can be
-/// unit-tested against a stub without touching SQLite.
-/// implements this interface; production wiring injects the same instance.
-///
-///
-/// Only the two methods the drain loop needs are exposed — the hot-path
-/// WriteAsync stays on
-/// (script-thread surface), separated by concern from the
-/// telemetry-actor surface so each side can be mocked independently.
-///
-public interface ISiteAuditQueue
-{
- ///
- /// Returns up to rows currently in
- /// ,
- /// oldest first. Idempotent — repeated calls before
- /// will yield the same rows again.
- ///
- Task> ReadPendingAsync(int limit, CancellationToken ct = default);
-
- ///
- /// Flips the supplied EventIds from
- /// to
- /// .
- /// Non-existent or already-forwarded ids are silent no-ops.
- ///
- Task MarkForwardedAsync(IReadOnlyList eventIds, CancellationToken ct = default);
-}
diff --git a/src/ScadaLink.AuditLog/Site/Telemetry/SiteAuditTelemetryActor.cs b/src/ScadaLink.AuditLog/Site/Telemetry/SiteAuditTelemetryActor.cs
index a820cf5..724e1d1 100644
--- a/src/ScadaLink.AuditLog/Site/Telemetry/SiteAuditTelemetryActor.cs
+++ b/src/ScadaLink.AuditLog/Site/Telemetry/SiteAuditTelemetryActor.cs
@@ -3,6 +3,7 @@ using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ScadaLink.AuditLog.Telemetry;
using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Communication.Grpc;
namespace ScadaLink.AuditLog.Site.Telemetry;
diff --git a/src/ScadaLink.Commons/Interfaces/IPartitionMaintenance.cs b/src/ScadaLink.Commons/Interfaces/IPartitionMaintenance.cs
new file mode 100644
index 0000000..b8b3ec5
--- /dev/null
+++ b/src/ScadaLink.Commons/Interfaces/IPartitionMaintenance.cs
@@ -0,0 +1,48 @@
+namespace ScadaLink.Commons.Interfaces;
+
+///
+/// Abstraction over the central AuditLog partition-function roll-forward
+/// operation. M6-T5 introduces a daily-cadence hosted service
+/// (AuditLogPartitionMaintenanceService) that calls
+/// to make sure
+/// pf_AuditLog_Month always has at least LookaheadMonths of
+/// future boundaries available — otherwise inserts past the highest
+/// boundary land in a single ever-growing tail partition that
+/// SwitchOutPartitionAsync cannot purge cleanly.
+///
+///
+///
+/// The interface lives in ScadaLink.Commons so the central hosted
+/// service in ScadaLink.AuditLog can depend on it without taking a
+/// reference on ScadaLink.ConfigurationDatabase; the EF-based
+/// implementation ships in
+/// ScadaLink.ConfigurationDatabase.Maintenance.AuditLogPartitionMaintenance
+/// and is registered by AddConfigurationDatabase.
+///
+///
+/// Both methods read sys.partition_range_values / mutate
+/// pf_AuditLog_Month via raw SQL — there is no EF model for a
+/// partition function. The interface deliberately exposes only the two
+/// operations the hosted service needs; it is not a general partition-DDL
+/// surface.
+///
+///
+public interface IPartitionMaintenance
+{
+ ///
+ /// Splits new monthly boundaries on pf_AuditLog_Month so the
+ /// function covers at least future
+ /// months relative to . Idempotent — a
+ /// boundary that already exists is skipped rather than re-issued.
+ /// Returns the boundaries actually added, in chronological order.
+ ///
+ Task> EnsureLookaheadAsync(int lookaheadMonths, CancellationToken ct = default);
+
+ ///
+ /// Reads the current maximum boundary value from
+ /// sys.partition_range_values for pf_AuditLog_Month.
+ /// Returns null when the partition function does not exist or
+ /// has no boundaries.
+ ///
+ Task GetMaxBoundaryAsync(CancellationToken ct = default);
+}
diff --git a/src/ScadaLink.Commons/Interfaces/Repositories/IAuditLogRepository.cs b/src/ScadaLink.Commons/Interfaces/Repositories/IAuditLogRepository.cs
index 7b15962..bcda482 100644
--- a/src/ScadaLink.Commons/Interfaces/Repositories/IAuditLogRepository.cs
+++ b/src/ScadaLink.Commons/Interfaces/Repositories/IAuditLogRepository.cs
@@ -45,12 +45,46 @@ public interface IAuditLogRepository
///
/// Switches out (purges) the monthly partition whose lower bound is
- /// . The honest M1 implementation throws
- /// : the UX_AuditLog_EventId unique
- /// index is non-partition-aligned (lives on [PRIMARY], not on
- /// ps_AuditLog_Month), so SQL Server rejects
- /// ALTER TABLE … SWITCH PARTITION until the drop-and-rebuild dance
- /// shipped by the M6 purge actor is in place.
+ /// and returns the approximate number
+ /// of rows discarded — sampled inside the transaction BEFORE the switch
+ /// so the row count reflects what the switch removed, not a post-purge
+ /// scan of a table that no longer exists.
///
- Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default);
+ ///
+ ///
+ /// Drop-and-rebuild dance. UX_AuditLog_EventId is intentionally
+ /// non-partition-aligned (it lives on [PRIMARY] so single-column
+ /// EventId uniqueness — required by —
+ /// can be enforced cheaply). SQL Server rejects
+ /// ALTER TABLE … SWITCH PARTITION while a non-aligned unique index
+ /// is present, so the M6 implementation drops the index, creates a staging
+ /// table with byte-identical schema, switches the partition's data into
+ /// staging, drops staging (discarding the rows), and rebuilds the unique
+ /// index. The CATCH branch guarantees the index is rebuilt even on partial
+ /// failure so the table never returns to live traffic without its
+ /// idempotency-supporting index.
+ ///
+ ///
+ /// Outage window. The dance briefly removes the unique index, so
+ /// concurrent calls during the switch
+ /// could in principle race past the IF NOT EXISTS check without the index
+ /// catching the duplicate. This is acceptable for the daily purge cadence
+ /// — the inserts that the IF NOT EXISTS check guards are themselves rare
+ /// enough that a sub-second collision window is operationally negligible,
+ /// and the composite PK still rejects same-(EventId, OccurredAtUtc) rows.
+ ///
+ ///
+ Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default);
+
+ ///
+ /// Returns the set of pf_AuditLog_Month partition lower-bound
+ /// boundaries whose partitions contain only rows with
+ /// strictly older than
+ /// . Boundaries whose partition is empty are
+ /// excluded (a no-op switch is wasted work). Used by the M6 purge actor
+ /// to enumerate retention-eligible months on every tick.
+ ///
+ Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold,
+ CancellationToken ct = default);
}
diff --git a/src/ScadaLink.Commons/Interfaces/Services/ISiteAuditQueue.cs b/src/ScadaLink.Commons/Interfaces/Services/ISiteAuditQueue.cs
new file mode 100644
index 0000000..c9e0462
--- /dev/null
+++ b/src/ScadaLink.Commons/Interfaces/Services/ISiteAuditQueue.cs
@@ -0,0 +1,87 @@
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Types;
+
+namespace ScadaLink.Commons.Interfaces.Services;
+
+///
+/// Site-local audit-log queue surface consumed by the site
+/// SiteAuditTelemetryActor drain loop and the M6
+/// SiteStreamGrpcServer.PullAuditEvents reconciliation handler.
+/// Extracted from SqliteAuditWriter so both consumers can be
+/// unit-tested against a stub without touching SQLite; the
+/// SqliteAuditWriter production type implements this interface
+/// and DI wires the same singleton instance to every consumer.
+///
+///
+/// Lives in Commons (rather than alongside SqliteAuditWriter in
+/// ScadaLink.AuditLog) because ScadaLink.Communication — which
+/// hosts the M6 gRPC pull handler — must depend on this interface and
+/// ScadaLink.AuditLog already depends on ScadaLink.Communication.
+/// Pulling the interface up to Commons breaks the would-be cycle while
+/// keeping the implementation in the AuditLog component.
+///
+/// Only the methods the drain and pull paths need are exposed — the
+/// hot-path WriteAsync stays on
+/// (script-thread surface), separated by concern so each side can be
+/// mocked independently.
+///
+public interface ISiteAuditQueue
+{
+ ///
+ /// Returns up to rows currently in
+ /// ,
+ /// oldest first. Idempotent — repeated calls before
+ /// will yield the same rows again.
+ ///
+ Task> ReadPendingAsync(int limit, CancellationToken ct = default);
+
+ ///
+ /// Flips the supplied EventIds from
+ /// to
+ /// .
+ /// Non-existent or already-forwarded ids are silent no-ops.
+ ///
+ Task MarkForwardedAsync(IReadOnlyList eventIds, CancellationToken ct = default);
+
+ ///
+ /// M6 reconciliation-pull read surface: returns up to
+ /// rows whose >=
+ /// and whose is still
+ /// or
+ /// .
+ ///
+ ///
+ /// Rows in the brief race window between site-Forwarded and central-ingest are
+ /// intentionally included: the central reconciliation puller dedups on
+ /// , so re-shipping is safe and avoids losing rows
+ /// whose telemetry ack was acted on locally but never landed centrally. Ordering
+ /// is oldest first with
+ /// as the deterministic tiebreaker.
+ ///
+ Task> ReadPendingSinceAsync(
+ DateTime sinceUtc, int batchSize, CancellationToken ct = default);
+
+ ///
+ /// M6 reconciliation-pull commit surface: flips the supplied EventIds to
+ /// ,
+ /// but ONLY for rows currently in
+ /// or
+ /// .
+ /// Rows already in
+ /// are left untouched (idempotent re-call). Non-existent ids are silent no-ops.
+ ///
+ Task MarkReconciledAsync(IReadOnlyList eventIds, CancellationToken ct = default);
+
+ ///
+ /// M6 Bundle E (T6) health-metric surface: returns a point-in-time snapshot
+ /// of the site queue's pending count + oldest pending timestamp + on-disk
+ /// SQLite file size. Surfaced on
+ /// as
+ /// SiteAuditBacklog by the periodic SiteAuditBacklogReporter
+ /// hosted service so a stuck site→central drain is visible on the central
+ /// health dashboard. Safe to call concurrently with hot-path writes —
+ /// implementations are expected to take the same connection lock used by
+ /// the hot-path INSERT batch and the drain queries.
+ ///
+ Task GetBacklogStatsAsync(CancellationToken ct = default);
+}
diff --git a/src/ScadaLink.Commons/Messages/Health/SiteHealthReport.cs b/src/ScadaLink.Commons/Messages/Health/SiteHealthReport.cs
index bba4c8d..5567037 100644
--- a/src/ScadaLink.Commons/Messages/Health/SiteHealthReport.cs
+++ b/src/ScadaLink.Commons/Messages/Health/SiteHealthReport.cs
@@ -1,3 +1,4 @@
+using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
namespace ScadaLink.Commons.Messages.Health;
@@ -32,7 +33,14 @@ public record SiteHealthReport(
// marker). Surfaces a misconfigured / catastrophic regex on
// /monitoring/health. Defaults to 0 for back-compat with existing
// producers and tests that don't construct the field.
- int AuditRedactionFailure = 0);
+ int AuditRedactionFailure = 0,
+ // Audit Log (#23) M6 Bundle E (T6): point-in-time snapshot of the
+ // site-local SQLite audit-log queue (pending count, oldest pending row,
+ // on-disk bytes). Populated by the site-side SiteAuditBacklogReporter
+ // hosted service every 30 s. Defaults to null so existing producers /
+ // tests that don't refresh the snapshot stay valid; the central health
+ // surface treats null as "no data yet" rather than a zeroed queue.
+ SiteAuditBacklogSnapshot? SiteAuditBacklog = null);
///
/// Broadcast wrapper used between central nodes to keep per-node
diff --git a/src/ScadaLink.Commons/Types/SiteAuditBacklogSnapshot.cs b/src/ScadaLink.Commons/Types/SiteAuditBacklogSnapshot.cs
new file mode 100644
index 0000000..687a743
--- /dev/null
+++ b/src/ScadaLink.Commons/Types/SiteAuditBacklogSnapshot.cs
@@ -0,0 +1,32 @@
+namespace ScadaLink.Commons.Types;
+
+///
+/// Audit Log (#23) M6 Bundle E (T6) — point-in-time snapshot of the site-local
+/// SQLite audit-log queue health, surfaced on
+/// as
+/// SiteAuditBacklog and refreshed periodically by the
+/// SiteAuditBacklogReporter hosted service.
+///
+///
+/// Number of rows currently in
+/// — i.e.
+/// not yet acknowledged by central via either the push-telemetry or
+/// reconciliation-pull paths. A persistently non-zero value with rising
+/// indicates the site→central drain isn't
+/// keeping up.
+///
+///
+/// of
+/// the oldest Pending row, or null if the queue is empty. Used by ops
+/// to compute backlog age without a separate query.
+///
+///
+/// Size of the SQLite file on disk in bytes, or 0 if the writer is
+/// running against an in-memory database. Mirrors the 7-day retention
+/// invariant (alog.md §10) — a steady file-size growth past the retention
+/// window points at a stuck purge or a stuck forwarder.
+///
+public sealed record SiteAuditBacklogSnapshot(
+ int PendingCount,
+ DateTime? OldestPendingUtc,
+ long OnDiskBytes);
diff --git a/src/ScadaLink.Communication/Grpc/SiteStreamGrpcServer.cs b/src/ScadaLink.Communication/Grpc/SiteStreamGrpcServer.cs
index 1da14ec..8a92027 100644
--- a/src/ScadaLink.Communication/Grpc/SiteStreamGrpcServer.cs
+++ b/src/ScadaLink.Communication/Grpc/SiteStreamGrpcServer.cs
@@ -5,6 +5,7 @@ using Grpc.Core;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Messages.Audit;
using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
@@ -36,6 +37,13 @@ public class SiteStreamGrpcServer : SiteStreamService.SiteStreamServiceBase
// calls are sub-100 ms in steady state; a generous timeout absorbs a slow
// MSSQL connection without surfacing as a gRPC failure on a healthy site.
private static readonly TimeSpan AuditIngestAskTimeout = TimeSpan.FromSeconds(30);
+ // Audit Log (#23 M6): site-local queue handed in by AkkaHostedService on
+ // site roles so the central reconciliation puller's PullAuditEvents RPC
+ // can read Pending/Forwarded rows. Null when not wired (e.g. central-only
+ // host or test composing the server in isolation) — the handler treats
+ // the missing queue as "nothing to ship" and returns an empty response so
+ // central retries on its next reconciliation cycle.
+ private ISiteAuditQueue? _siteAuditQueue;
///
/// Test-only constructor — kept internal so the DI container sees a
@@ -102,6 +110,20 @@ public class SiteStreamGrpcServer : SiteStreamService.SiteStreamServiceBase
_auditIngestActor = proxy;
}
+ ///
+ /// Hands the site-local (the same
+ /// SqliteAuditWriter singleton that backs
+ /// on the script thread) to the gRPC server so the M6
+ /// RPC can serve central's reconciliation
+ /// pulls. Mirrors : wired post-construction
+ /// because the queue and the gRPC server are both DI singletons brought up
+ /// in independent orders on site startup.
+ ///
+ public void SetSiteAuditQueue(ISiteAuditQueue queue)
+ {
+ _siteAuditQueue = queue;
+ }
+
///
/// Number of currently active streaming subscriptions. Exposed for diagnostics.
///
@@ -361,6 +383,144 @@ public class SiteStreamGrpcServer : SiteStreamService.SiteStreamServiceBase
return ack;
}
+ ///
+ /// Audit Log (#23) M6 reconciliation pull RPC. Central asks the site for any
+ /// AuditLog rows whose OccurredAtUtc >= since_utc and whose
+ /// ForwardState is still Pending or Forwarded (i.e. not
+ /// yet confirmed reconciled), bounded by batch_size. The site responds
+ /// with the rows AND flips them to
+ ///
+ /// AFTER serializing the response. The flip is best-effort — if it fails
+ /// (e.g. SQLite disposed mid-call), rows stay Pending/Forwarded and central
+ /// pulls them again on the next reconciliation cycle. Idempotent.
+ ///
+ ///
+ /// When is not wired (central-only host or a
+ /// composition-root test exercising the server in isolation) the RPC returns
+ /// an empty response — central treats that as "nothing to ship" and retries
+ /// on its next cycle, which is the same self-healing semantics as the
+ /// SetAuditIngestActor wiring race window.
+ ///
+ public override async Task PullAuditEvents(
+ PullAuditEventsRequest request,
+ ServerCallContext context)
+ {
+ var queue = _siteAuditQueue;
+ if (queue is null)
+ {
+ _logger.LogWarning(
+ "PullAuditEvents invoked before SetSiteAuditQueue was called; returning empty response.");
+ return new PullAuditEventsResponse();
+ }
+
+ if (request.BatchSize <= 0)
+ {
+ // Mirrors the SubscribeInstance guard: reject malformed requests
+ // cleanly with InvalidArgument so the caller doesn't see a generic
+ // RpcException from the underlying SQLite parameter validation.
+ throw new RpcException(new GrpcStatus(
+ StatusCode.InvalidArgument, "batch_size must be > 0"));
+ }
+
+ // sinceUtc defaults to DateTime.MinValue when the wrapper is absent —
+ // i.e. "pull from the beginning of recorded history", which is the
+ // intended behaviour for the very first reconciliation cycle.
+ var since = request.SinceUtc?.ToDateTime().ToUniversalTime() ?? DateTime.MinValue;
+
+ IReadOnlyList events;
+ try
+ {
+ events = await queue.ReadPendingSinceAsync(
+ since, request.BatchSize, context.CancellationToken);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex,
+ "ReadPendingSinceAsync failed for since={Since} batch={Batch}; returning empty response.",
+ since, request.BatchSize);
+ return new PullAuditEventsResponse();
+ }
+
+ var response = new PullAuditEventsResponse
+ {
+ // batch_size saturated → tell central to issue a follow-up pull
+ // with an advanced cursor. The site doesn't compute the cursor —
+ // central walks it forward from the last returned OccurredAtUtc.
+ MoreAvailable = events.Count >= request.BatchSize,
+ };
+ foreach (var evt in events)
+ {
+ response.Events.Add(AuditEventToDto(evt));
+ }
+
+ // Flip to Reconciled AFTER projecting the response so a fault below the
+ // try/catch (mid-response, mid-flip) leaves the rows in Pending/Forwarded
+ // and central pulls them again next cycle. The flip itself is
+ // best-effort — its failure is a warning, not a fault, because central
+ // will dedup on EventId on the next pull.
+ var ids = new List(events.Count);
+ foreach (var evt in events)
+ {
+ ids.Add(evt.EventId);
+ }
+
+ if (ids.Count > 0)
+ {
+ try
+ {
+ await queue.MarkReconciledAsync(ids, context.CancellationToken);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogWarning(ex,
+ "MarkReconciledAsync failed after PullAuditEvents response of {Count} rows; rows stay Pending for retry.",
+ ids.Count);
+ }
+ }
+
+ return response;
+ }
+
+ ///
+ /// Inlined audit-event entity→DTO translation. Keep in sync with
+ /// AuditEventMapper.ToDto in ScadaLink.AuditLog.Telemetry —
+ /// the project-reference cycle (AuditLog → Communication) prevents calling
+ /// the AuditLog mapper directly. The shape mirrors the FromDto pair above.
+ ///
+ private static AuditEventDto AuditEventToDto(AuditEvent evt)
+ {
+ var dto = new AuditEventDto
+ {
+ EventId = evt.EventId.ToString(),
+ OccurredAtUtc = Google.Protobuf.WellKnownTypes.Timestamp.FromDateTime(EnsureUtc(evt.OccurredAtUtc)),
+ Channel = evt.Channel.ToString(),
+ Kind = evt.Kind.ToString(),
+ CorrelationId = evt.CorrelationId?.ToString() ?? string.Empty,
+ SourceSiteId = evt.SourceSiteId ?? string.Empty,
+ SourceInstanceId = evt.SourceInstanceId ?? string.Empty,
+ SourceScript = evt.SourceScript ?? string.Empty,
+ Actor = evt.Actor ?? string.Empty,
+ Target = evt.Target ?? string.Empty,
+ Status = evt.Status.ToString(),
+ ErrorMessage = evt.ErrorMessage ?? string.Empty,
+ ErrorDetail = evt.ErrorDetail ?? string.Empty,
+ RequestSummary = evt.RequestSummary ?? string.Empty,
+ ResponseSummary = evt.ResponseSummary ?? string.Empty,
+ PayloadTruncated = evt.PayloadTruncated,
+ Extra = evt.Extra ?? string.Empty,
+ };
+
+ if (evt.HttpStatus.HasValue) dto.HttpStatus = evt.HttpStatus.Value;
+ if (evt.DurationMs.HasValue) dto.DurationMs = evt.DurationMs.Value;
+
+ return dto;
+ }
+
+ private static DateTime EnsureUtc(DateTime value) =>
+ value.Kind == DateTimeKind.Utc
+ ? value
+ : DateTime.SpecifyKind(value.ToUniversalTime(), DateTimeKind.Utc);
+
private static string? NullIfEmpty(string? value) =>
string.IsNullOrEmpty(value) ? null : value;
diff --git a/src/ScadaLink.Communication/Protos/sitestream.proto b/src/ScadaLink.Communication/Protos/sitestream.proto
index 43ffbe3..5ceb709 100644
--- a/src/ScadaLink.Communication/Protos/sitestream.proto
+++ b/src/ScadaLink.Communication/Protos/sitestream.proto
@@ -9,6 +9,7 @@ service SiteStreamService {
rpc SubscribeInstance(InstanceStreamRequest) returns (stream SiteStreamEvent);
rpc IngestAuditEvents(AuditEventBatch) returns (IngestAck);
rpc IngestCachedTelemetry(CachedTelemetryBatch) returns (IngestAck);
+ rpc PullAuditEvents(PullAuditEventsRequest) returns (PullAuditEventsResponse);
}
message InstanceStreamRequest {
@@ -119,3 +120,19 @@ message CachedTelemetryPacket {
}
message CachedTelemetryBatch { repeated CachedTelemetryPacket packets = 1; }
+
+// Audit Log (#23) M6 reconciliation pull: central→site request for any
+// site-local AuditLog rows with OccurredAtUtc >= since_utc that have not yet
+// been ingested centrally (ForwardState in {Pending, Forwarded}). The site
+// flips returned rows to Reconciled after the response is on the wire.
+// more_available signals batch_size was saturated so the caller knows to
+// issue a follow-up pull with an advanced since_utc cursor.
+message PullAuditEventsRequest {
+ google.protobuf.Timestamp since_utc = 1;
+ int32 batch_size = 2;
+}
+
+message PullAuditEventsResponse {
+ repeated AuditEventDto events = 1;
+ bool more_available = 2;
+}
diff --git a/src/ScadaLink.Communication/SiteStreamGrpc/Sitestream.cs b/src/ScadaLink.Communication/SiteStreamGrpc/Sitestream.cs
index 9639242..ccac2bb 100644
--- a/src/ScadaLink.Communication/SiteStreamGrpc/Sitestream.cs
+++ b/src/ScadaLink.Communication/SiteStreamGrpc/Sitestream.cs
@@ -68,21 +68,27 @@ namespace ScadaLink.Communication.Grpc {
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- "TF9ISUdIX0hJR0gQBDKFAgoRU2l0ZVN0cmVhbVNlcnZpY2USVQoRU3Vic2Ny",
- "aWJlSW5zdGFuY2USIS5zaXRlc3RyZWFtLkluc3RhbmNlU3RyZWFtUmVxdWVz",
- "dBobLnNpdGVzdHJlYW0uU2l0ZVN0cmVhbUV2ZW50MAESRwoRSW5nZXN0QXVk",
- "aXRFdmVudHMSGy5zaXRlc3RyZWFtLkF1ZGl0RXZlbnRCYXRjaBoVLnNpdGVz",
- "dHJlYW0uSW5nZXN0QWNrElAKFUluZ2VzdENhY2hlZFRlbGVtZXRyeRIgLnNp",
- "dGVzdHJlYW0uQ2FjaGVkVGVsZW1ldHJ5QmF0Y2gaFS5zaXRlc3RyZWFtLklu",
- "Z2VzdEFja0IfqgIcU2NhZGFMaW5rLkNvbW11bmljYXRpb24uR3JwY2IGcHJv",
- "dG8z"));
+ "a2V0IlsKFlB1bGxBdWRpdEV2ZW50c1JlcXVlc3QSLQoJc2luY2VfdXRjGAEg",
+ "ASgLMhouZ29vZ2xlLnByb3RvYnVmLlRpbWVzdGFtcBISCgpiYXRjaF9zaXpl",
+ "GAIgASgFIlwKF1B1bGxBdWRpdEV2ZW50c1Jlc3BvbnNlEikKBmV2ZW50cxgB",
+ "IAMoCzIZLnNpdGVzdHJlYW0uQXVkaXRFdmVudER0bxIWCg5tb3JlX2F2YWls",
+ "YWJsZRgCIAEoCCpcCgdRdWFsaXR5EhcKE1FVQUxJVFlfVU5TUEVDSUZJRUQQ",
+ "ABIQCgxRVUFMSVRZX0dPT0QQARIVChFRVUFMSVRZX1VOQ0VSVEFJThACEg8K",
+ "C1FVQUxJVFlfQkFEEAMqXQoOQWxhcm1TdGF0ZUVudW0SGwoXQUxBUk1fU1RB",
+ "VEVfVU5TUEVDSUZJRUQQABIWChJBTEFSTV9TVEFURV9OT1JNQUwQARIWChJB",
+ "TEFSTV9TVEFURV9BQ1RJVkUQAiqFAQoOQWxhcm1MZXZlbEVudW0SFAoQQUxB",
+ "Uk1fTEVWRUxfTk9ORRAAEhMKD0FMQVJNX0xFVkVMX0xPVxABEhcKE0FMQVJN",
+ "X0xFVkVMX0xPV19MT1cQAhIUChBBTEFSTV9MRVZFTF9ISUdIEAMSGQoVQUxB",
+ "Uk1fTEVWRUxfSElHSF9ISUdIEAQy4QIKEVNpdGVTdHJlYW1TZXJ2aWNlElUK",
+ "EVN1YnNjcmliZUluc3RhbmNlEiEuc2l0ZXN0cmVhbS5JbnN0YW5jZVN0cmVh",
+ "bVJlcXVlc3QaGy5zaXRlc3RyZWFtLlNpdGVTdHJlYW1FdmVudDABEkcKEUlu",
+ "Z2VzdEF1ZGl0RXZlbnRzEhsuc2l0ZXN0cmVhbS5BdWRpdEV2ZW50QmF0Y2ga",
+ "FS5zaXRlc3RyZWFtLkluZ2VzdEFjaxJQChVJbmdlc3RDYWNoZWRUZWxlbWV0",
+ "cnkSIC5zaXRlc3RyZWFtLkNhY2hlZFRlbGVtZXRyeUJhdGNoGhUuc2l0ZXN0",
+ "cmVhbS5Jbmdlc3RBY2sSWgoPUHVsbEF1ZGl0RXZlbnRzEiIuc2l0ZXN0cmVh",
+ "bS5QdWxsQXVkaXRFdmVudHNSZXF1ZXN0GiMuc2l0ZXN0cmVhbS5QdWxsQXVk",
+ "aXRFdmVudHNSZXNwb25zZUIfqgIcU2NhZGFMaW5rLkNvbW11bmljYXRpb24u",
+ "R3JwY2IGcHJvdG8z"));
descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
new pbr::FileDescriptor[] { global::Google.Protobuf.WellKnownTypes.TimestampReflection.Descriptor, global::Google.Protobuf.WellKnownTypes.WrappersReflection.Descriptor, },
new pbr::GeneratedClrTypeInfo(new[] {typeof(global::ScadaLink.Communication.Grpc.Quality), typeof(global::ScadaLink.Communication.Grpc.AlarmStateEnum), typeof(global::ScadaLink.Communication.Grpc.AlarmLevelEnum), }, null, new pbr::GeneratedClrTypeInfo[] {
@@ -95,7 +101,9 @@ namespace ScadaLink.Communication.Grpc {
new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.IngestAck), global::ScadaLink.Communication.Grpc.IngestAck.Parser, new[]{ "AcceptedEventIds" }, null, null, null, null),
new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.SiteCallOperationalDto), global::ScadaLink.Communication.Grpc.SiteCallOperationalDto.Parser, new[]{ "TrackedOperationId", "Channel", "Target", "SourceSite", "Status", "RetryCount", "LastError", "HttpStatus", "CreatedAtUtc", "UpdatedAtUtc", "TerminalAtUtc" }, null, null, null, null),
new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.CachedTelemetryPacket), global::ScadaLink.Communication.Grpc.CachedTelemetryPacket.Parser, new[]{ "AuditEvent", "Operational" }, null, null, null, null),
- new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.CachedTelemetryBatch), global::ScadaLink.Communication.Grpc.CachedTelemetryBatch.Parser, new[]{ "Packets" }, null, null, null, null)
+ new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.CachedTelemetryBatch), global::ScadaLink.Communication.Grpc.CachedTelemetryBatch.Parser, new[]{ "Packets" }, null, null, null, null),
+ new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest), global::ScadaLink.Communication.Grpc.PullAuditEventsRequest.Parser, new[]{ "SinceUtc", "BatchSize" }, null, null, null, null),
+ new pbr::GeneratedClrTypeInfo(typeof(global::ScadaLink.Communication.Grpc.PullAuditEventsResponse), global::ScadaLink.Communication.Grpc.PullAuditEventsResponse.Parser, new[]{ "Events", "MoreAvailable" }, null, null, null, null)
}));
}
#endregion
@@ -3862,6 +3870,482 @@ namespace ScadaLink.Communication.Grpc {
}
+ ///
+ /// Audit Log (#23) M6 reconciliation pull: central→site request for any
+ /// site-local AuditLog rows with OccurredAtUtc >= since_utc that have not yet
+ /// been ingested centrally (ForwardState in {Pending, Forwarded}). The site
+ /// flips returned rows to Reconciled after the response is on the wire.
+ /// more_available signals batch_size was saturated so the caller knows to
+ /// issue a follow-up pull with an advanced since_utc cursor.
+ ///
+ [global::System.Diagnostics.DebuggerDisplayAttribute("{ToString(),nq}")]
+ public sealed partial class PullAuditEventsRequest : pb::IMessage
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ , pb::IBufferMessage
+ #endif
+ {
+ private static readonly pb::MessageParser _parser = new pb::MessageParser(() => new PullAuditEventsRequest());
+ private pb::UnknownFieldSet _unknownFields;
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public static pb::MessageParser Parser { get { return _parser; } }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public static pbr::MessageDescriptor Descriptor {
+ get { return global::ScadaLink.Communication.Grpc.SitestreamReflection.Descriptor.MessageTypes[10]; }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ pbr::MessageDescriptor pb::IMessage.Descriptor {
+ get { return Descriptor; }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsRequest() {
+ OnConstruction();
+ }
+
+ partial void OnConstruction();
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsRequest(PullAuditEventsRequest other) : this() {
+ sinceUtc_ = other.sinceUtc_ != null ? other.sinceUtc_.Clone() : null;
+ batchSize_ = other.batchSize_;
+ _unknownFields = pb::UnknownFieldSet.Clone(other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsRequest Clone() {
+ return new PullAuditEventsRequest(this);
+ }
+
+ /// Field number for the "since_utc" field.
+ public const int SinceUtcFieldNumber = 1;
+ private global::Google.Protobuf.WellKnownTypes.Timestamp sinceUtc_;
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public global::Google.Protobuf.WellKnownTypes.Timestamp SinceUtc {
+ get { return sinceUtc_; }
+ set {
+ sinceUtc_ = value;
+ }
+ }
+
+ /// Field number for the "batch_size" field.
+ public const int BatchSizeFieldNumber = 2;
+ private int batchSize_;
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public int BatchSize {
+ get { return batchSize_; }
+ set {
+ batchSize_ = value;
+ }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override bool Equals(object other) {
+ return Equals(other as PullAuditEventsRequest);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public bool Equals(PullAuditEventsRequest other) {
+ if (ReferenceEquals(other, null)) {
+ return false;
+ }
+ if (ReferenceEquals(other, this)) {
+ return true;
+ }
+ if (!object.Equals(SinceUtc, other.SinceUtc)) return false;
+ if (BatchSize != other.BatchSize) return false;
+ return Equals(_unknownFields, other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override int GetHashCode() {
+ int hash = 1;
+ if (sinceUtc_ != null) hash ^= SinceUtc.GetHashCode();
+ if (BatchSize != 0) hash ^= BatchSize.GetHashCode();
+ if (_unknownFields != null) {
+ hash ^= _unknownFields.GetHashCode();
+ }
+ return hash;
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override string ToString() {
+ return pb::JsonFormatter.ToDiagnosticString(this);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void WriteTo(pb::CodedOutputStream output) {
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ output.WriteRawMessage(this);
+ #else
+ if (sinceUtc_ != null) {
+ output.WriteRawTag(10);
+ output.WriteMessage(SinceUtc);
+ }
+ if (BatchSize != 0) {
+ output.WriteRawTag(16);
+ output.WriteInt32(BatchSize);
+ }
+ if (_unknownFields != null) {
+ _unknownFields.WriteTo(output);
+ }
+ #endif
+ }
+
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ void pb::IBufferMessage.InternalWriteTo(ref pb::WriteContext output) {
+ if (sinceUtc_ != null) {
+ output.WriteRawTag(10);
+ output.WriteMessage(SinceUtc);
+ }
+ if (BatchSize != 0) {
+ output.WriteRawTag(16);
+ output.WriteInt32(BatchSize);
+ }
+ if (_unknownFields != null) {
+ _unknownFields.WriteTo(ref output);
+ }
+ }
+ #endif
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public int CalculateSize() {
+ int size = 0;
+ if (sinceUtc_ != null) {
+ size += 1 + pb::CodedOutputStream.ComputeMessageSize(SinceUtc);
+ }
+ if (BatchSize != 0) {
+ size += 1 + pb::CodedOutputStream.ComputeInt32Size(BatchSize);
+ }
+ if (_unknownFields != null) {
+ size += _unknownFields.CalculateSize();
+ }
+ return size;
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void MergeFrom(PullAuditEventsRequest other) {
+ if (other == null) {
+ return;
+ }
+ if (other.sinceUtc_ != null) {
+ if (sinceUtc_ == null) {
+ SinceUtc = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+ }
+ SinceUtc.MergeFrom(other.SinceUtc);
+ }
+ if (other.BatchSize != 0) {
+ BatchSize = other.BatchSize;
+ }
+ _unknownFields = pb::UnknownFieldSet.MergeFrom(_unknownFields, other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void MergeFrom(pb::CodedInputStream input) {
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ input.ReadRawMessage(this);
+ #else
+ uint tag;
+ while ((tag = input.ReadTag()) != 0) {
+ if ((tag & 7) == 4) {
+ // Abort on any end group tag.
+ return;
+ }
+ switch(tag) {
+ default:
+ _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+ break;
+ case 10: {
+ if (sinceUtc_ == null) {
+ SinceUtc = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+ }
+ input.ReadMessage(SinceUtc);
+ break;
+ }
+ case 16: {
+ BatchSize = input.ReadInt32();
+ break;
+ }
+ }
+ }
+ #endif
+ }
+
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
+ uint tag;
+ while ((tag = input.ReadTag()) != 0) {
+ if ((tag & 7) == 4) {
+ // Abort on any end group tag.
+ return;
+ }
+ switch(tag) {
+ default:
+ _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, ref input);
+ break;
+ case 10: {
+ if (sinceUtc_ == null) {
+ SinceUtc = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+ }
+ input.ReadMessage(SinceUtc);
+ break;
+ }
+ case 16: {
+ BatchSize = input.ReadInt32();
+ break;
+ }
+ }
+ }
+ }
+ #endif
+
+ }
+
+ [global::System.Diagnostics.DebuggerDisplayAttribute("{ToString(),nq}")]
+ public sealed partial class PullAuditEventsResponse : pb::IMessage
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ , pb::IBufferMessage
+ #endif
+ {
+ private static readonly pb::MessageParser _parser = new pb::MessageParser(() => new PullAuditEventsResponse());
+ private pb::UnknownFieldSet _unknownFields;
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public static pb::MessageParser Parser { get { return _parser; } }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public static pbr::MessageDescriptor Descriptor {
+ get { return global::ScadaLink.Communication.Grpc.SitestreamReflection.Descriptor.MessageTypes[11]; }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ pbr::MessageDescriptor pb::IMessage.Descriptor {
+ get { return Descriptor; }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsResponse() {
+ OnConstruction();
+ }
+
+ partial void OnConstruction();
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsResponse(PullAuditEventsResponse other) : this() {
+ events_ = other.events_.Clone();
+ moreAvailable_ = other.moreAvailable_;
+ _unknownFields = pb::UnknownFieldSet.Clone(other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public PullAuditEventsResponse Clone() {
+ return new PullAuditEventsResponse(this);
+ }
+
+ /// Field number for the "events" field.
+ public const int EventsFieldNumber = 1;
+ private static readonly pb::FieldCodec _repeated_events_codec
+ = pb::FieldCodec.ForMessage(10, global::ScadaLink.Communication.Grpc.AuditEventDto.Parser);
+ private readonly pbc::RepeatedField events_ = new pbc::RepeatedField();
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public pbc::RepeatedField Events {
+ get { return events_; }
+ }
+
+ /// Field number for the "more_available" field.
+ public const int MoreAvailableFieldNumber = 2;
+ private bool moreAvailable_;
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public bool MoreAvailable {
+ get { return moreAvailable_; }
+ set {
+ moreAvailable_ = value;
+ }
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override bool Equals(object other) {
+ return Equals(other as PullAuditEventsResponse);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public bool Equals(PullAuditEventsResponse other) {
+ if (ReferenceEquals(other, null)) {
+ return false;
+ }
+ if (ReferenceEquals(other, this)) {
+ return true;
+ }
+ if(!events_.Equals(other.events_)) return false;
+ if (MoreAvailable != other.MoreAvailable) return false;
+ return Equals(_unknownFields, other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override int GetHashCode() {
+ int hash = 1;
+ hash ^= events_.GetHashCode();
+ if (MoreAvailable != false) hash ^= MoreAvailable.GetHashCode();
+ if (_unknownFields != null) {
+ hash ^= _unknownFields.GetHashCode();
+ }
+ return hash;
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public override string ToString() {
+ return pb::JsonFormatter.ToDiagnosticString(this);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void WriteTo(pb::CodedOutputStream output) {
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ output.WriteRawMessage(this);
+ #else
+ events_.WriteTo(output, _repeated_events_codec);
+ if (MoreAvailable != false) {
+ output.WriteRawTag(16);
+ output.WriteBool(MoreAvailable);
+ }
+ if (_unknownFields != null) {
+ _unknownFields.WriteTo(output);
+ }
+ #endif
+ }
+
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ void pb::IBufferMessage.InternalWriteTo(ref pb::WriteContext output) {
+ events_.WriteTo(ref output, _repeated_events_codec);
+ if (MoreAvailable != false) {
+ output.WriteRawTag(16);
+ output.WriteBool(MoreAvailable);
+ }
+ if (_unknownFields != null) {
+ _unknownFields.WriteTo(ref output);
+ }
+ }
+ #endif
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public int CalculateSize() {
+ int size = 0;
+ size += events_.CalculateSize(_repeated_events_codec);
+ if (MoreAvailable != false) {
+ size += 1 + 1;
+ }
+ if (_unknownFields != null) {
+ size += _unknownFields.CalculateSize();
+ }
+ return size;
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void MergeFrom(PullAuditEventsResponse other) {
+ if (other == null) {
+ return;
+ }
+ events_.Add(other.events_);
+ if (other.MoreAvailable != false) {
+ MoreAvailable = other.MoreAvailable;
+ }
+ _unknownFields = pb::UnknownFieldSet.MergeFrom(_unknownFields, other._unknownFields);
+ }
+
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ public void MergeFrom(pb::CodedInputStream input) {
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ input.ReadRawMessage(this);
+ #else
+ uint tag;
+ while ((tag = input.ReadTag()) != 0) {
+ if ((tag & 7) == 4) {
+ // Abort on any end group tag.
+ return;
+ }
+ switch(tag) {
+ default:
+ _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+ break;
+ case 10: {
+ events_.AddEntriesFrom(input, _repeated_events_codec);
+ break;
+ }
+ case 16: {
+ MoreAvailable = input.ReadBool();
+ break;
+ }
+ }
+ }
+ #endif
+ }
+
+ #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+ [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+ [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
+ void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
+ uint tag;
+ while ((tag = input.ReadTag()) != 0) {
+ if ((tag & 7) == 4) {
+ // Abort on any end group tag.
+ return;
+ }
+ switch(tag) {
+ default:
+ _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, ref input);
+ break;
+ case 10: {
+ events_.AddEntriesFrom(ref input, _repeated_events_codec);
+ break;
+ }
+ case 16: {
+ MoreAvailable = input.ReadBool();
+ break;
+ }
+ }
+ }
+ }
+ #endif
+
+ }
+
#endregion
}
diff --git a/src/ScadaLink.Communication/SiteStreamGrpc/SitestreamGrpc.cs b/src/ScadaLink.Communication/SiteStreamGrpc/SitestreamGrpc.cs
index e7b9b33..d5fd944 100644
--- a/src/ScadaLink.Communication/SiteStreamGrpc/SitestreamGrpc.cs
+++ b/src/ScadaLink.Communication/SiteStreamGrpc/SitestreamGrpc.cs
@@ -55,6 +55,10 @@ namespace ScadaLink.Communication.Grpc {
static readonly grpc::Marshaller __Marshaller_sitestream_IngestAck = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.IngestAck.Parser));
[global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
static readonly grpc::Marshaller __Marshaller_sitestream_CachedTelemetryBatch = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.CachedTelemetryBatch.Parser));
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ static readonly grpc::Marshaller __Marshaller_sitestream_PullAuditEventsRequest = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.PullAuditEventsRequest.Parser));
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ static readonly grpc::Marshaller __Marshaller_sitestream_PullAuditEventsResponse = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.PullAuditEventsResponse.Parser));
[global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
static readonly grpc::Method __Method_SubscribeInstance = new grpc::Method(
@@ -80,6 +84,14 @@ namespace ScadaLink.Communication.Grpc {
__Marshaller_sitestream_CachedTelemetryBatch,
__Marshaller_sitestream_IngestAck);
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ static readonly grpc::Method __Method_PullAuditEvents = new grpc::Method(
+ grpc::MethodType.Unary,
+ __ServiceName,
+ "PullAuditEvents",
+ __Marshaller_sitestream_PullAuditEventsRequest,
+ __Marshaller_sitestream_PullAuditEventsResponse);
+
/// Service descriptor
public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor
{
@@ -108,6 +120,12 @@ namespace ScadaLink.Communication.Grpc {
throw new grpc::RpcException(new grpc::Status(grpc::StatusCode.Unimplemented, ""));
}
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ public virtual global::System.Threading.Tasks.Task PullAuditEvents(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest request, grpc::ServerCallContext context)
+ {
+ throw new grpc::RpcException(new grpc::Status(grpc::StatusCode.Unimplemented, ""));
+ }
+
}
/// Client for SiteStreamService
@@ -187,6 +205,26 @@ namespace ScadaLink.Communication.Grpc {
{
return CallInvoker.AsyncUnaryCall(__Method_IngestCachedTelemetry, null, options, request);
}
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ public virtual global::ScadaLink.Communication.Grpc.PullAuditEventsResponse PullAuditEvents(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest request, grpc::Metadata headers = null, global::System.DateTime? deadline = null, global::System.Threading.CancellationToken cancellationToken = default(global::System.Threading.CancellationToken))
+ {
+ return PullAuditEvents(request, new grpc::CallOptions(headers, deadline, cancellationToken));
+ }
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ public virtual global::ScadaLink.Communication.Grpc.PullAuditEventsResponse PullAuditEvents(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest request, grpc::CallOptions options)
+ {
+ return CallInvoker.BlockingUnaryCall(__Method_PullAuditEvents, null, options, request);
+ }
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ public virtual grpc::AsyncUnaryCall PullAuditEventsAsync(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest request, grpc::Metadata headers = null, global::System.DateTime? deadline = null, global::System.Threading.CancellationToken cancellationToken = default(global::System.Threading.CancellationToken))
+ {
+ return PullAuditEventsAsync(request, new grpc::CallOptions(headers, deadline, cancellationToken));
+ }
+ [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+ public virtual grpc::AsyncUnaryCall PullAuditEventsAsync(global::ScadaLink.Communication.Grpc.PullAuditEventsRequest request, grpc::CallOptions options)
+ {
+ return CallInvoker.AsyncUnaryCall(__Method_PullAuditEvents, null, options, request);
+ }
/// Creates a new instance of client from given ClientBaseConfiguration.
[global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
protected override SiteStreamServiceClient NewInstance(ClientBaseConfiguration configuration)
@@ -203,7 +241,8 @@ namespace ScadaLink.Communication.Grpc {
return grpc::ServerServiceDefinition.CreateBuilder()
.AddMethod(__Method_SubscribeInstance, serviceImpl.SubscribeInstance)
.AddMethod(__Method_IngestAuditEvents, serviceImpl.IngestAuditEvents)
- .AddMethod(__Method_IngestCachedTelemetry, serviceImpl.IngestCachedTelemetry).Build();
+ .AddMethod(__Method_IngestCachedTelemetry, serviceImpl.IngestCachedTelemetry)
+ .AddMethod(__Method_PullAuditEvents, serviceImpl.PullAuditEvents).Build();
}
/// Register service method with a service binder with or without implementation. Useful when customizing the service binding logic.
@@ -216,6 +255,7 @@ namespace ScadaLink.Communication.Grpc {
serviceBinder.AddMethod(__Method_SubscribeInstance, serviceImpl == null ? null : new grpc::ServerStreamingServerMethod(serviceImpl.SubscribeInstance));
serviceBinder.AddMethod(__Method_IngestAuditEvents, serviceImpl == null ? null : new grpc::UnaryServerMethod(serviceImpl.IngestAuditEvents));
serviceBinder.AddMethod(__Method_IngestCachedTelemetry, serviceImpl == null ? null : new grpc::UnaryServerMethod(serviceImpl.IngestCachedTelemetry));
+ serviceBinder.AddMethod(__Method_PullAuditEvents, serviceImpl == null ? null : new grpc::UnaryServerMethod(serviceImpl.PullAuditEvents));
}
}
diff --git a/src/ScadaLink.ConfigurationDatabase/Maintenance/AuditLogPartitionMaintenance.cs b/src/ScadaLink.ConfigurationDatabase/Maintenance/AuditLogPartitionMaintenance.cs
new file mode 100644
index 0000000..cdbd54b
--- /dev/null
+++ b/src/ScadaLink.ConfigurationDatabase/Maintenance/AuditLogPartitionMaintenance.cs
@@ -0,0 +1,218 @@
+using System.Globalization;
+using Microsoft.Data.SqlClient;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using ScadaLink.Commons.Interfaces;
+
+namespace ScadaLink.ConfigurationDatabase.Maintenance;
+
+///
+/// EF/SQL-Server implementation of that
+/// rolls forward pf_AuditLog_Month by issuing
+/// ALTER PARTITION FUNCTION … SPLIT RANGE for each missing future
+/// monthly boundary.
+///
+///
+///
+/// The class is scoped (registered alongside the other repositories in
+/// AddConfigurationDatabase) because it shares
+/// — the hosted service opens a per-tick DI scope, resolves a fresh instance,
+/// and lets the scope's DbContext dispose with it. The class itself
+/// holds no state between calls.
+///
+///
+/// Idempotency model. Each tick reads the current max boundary from
+/// sys.partition_range_values and only issues SPLIT RANGE for
+/// boundaries that strictly follow it — a boundary already covered is never
+/// re-issued, so the "boundary already exists" failure (SQL Server msg 7708
+/// / 7711) is avoided by construction rather than caught. The pre-check is
+/// cheaper than the alternative TRY/CATCH around every SPLIT call and also
+/// keeps the returned added list semantically precise.
+///
+///
+/// Why "first of next month". The migration seeds boundaries on the
+/// first-of-month at midnight UTC; we preserve that convention so the
+/// resulting partition layout is uniform.
+/// rounds an arbitrary timestamp up to the next first-of-month boundary
+/// (e.g. 2026-05-20 → 2026-06-01), and
+/// walks one month at a time from there.
+///
+///
+/// Permissions. The migration's scadalink_audit_purger role
+/// already carries ALTER ON SCHEMA::dbo, which is sufficient for
+/// ALTER PARTITION FUNCTION SPLIT RANGE. No additional grant is
+/// required.
+///
+///
+public sealed class AuditLogPartitionMaintenance : IPartitionMaintenance
+{
+ private const string PartitionFunctionName = "pf_AuditLog_Month";
+ private const string PartitionSchemeName = "ps_AuditLog_Month";
+ private const string TargetFileGroup = "PRIMARY";
+
+ private readonly ScadaLinkDbContext _context;
+ private readonly ILogger _logger;
+
+ public AuditLogPartitionMaintenance(
+ ScadaLinkDbContext context,
+ ILogger? logger = null)
+ {
+ _context = context ?? throw new ArgumentNullException(nameof(context));
+ _logger = logger ?? NullLogger.Instance;
+ }
+
+ ///
+ public async Task GetMaxBoundaryAsync(CancellationToken ct = default)
+ {
+ // CAST the sql_variant `value` column to datetime2(7) — every boundary in
+ // pf_AuditLog_Month is declared as datetime2(7) by the migration, so the
+ // cast never loses precision.
+ const string sql = @"
+SELECT MAX(CAST(rv.value AS datetime2(7)))
+FROM sys.partition_range_values rv
+INNER JOIN sys.partition_functions pf ON rv.function_id = pf.function_id
+WHERE pf.name = 'pf_AuditLog_Month';";
+
+ var conn = _context.Database.GetDbConnection();
+ var openedHere = false;
+ if (conn.State != System.Data.ConnectionState.Open)
+ {
+ await conn.OpenAsync(ct).ConfigureAwait(false);
+ openedHere = true;
+ }
+
+ try
+ {
+ await using var cmd = conn.CreateCommand();
+ cmd.CommandText = sql;
+ var raw = await cmd.ExecuteScalarAsync(ct).ConfigureAwait(false);
+ if (raw is null || raw is DBNull)
+ {
+ return null;
+ }
+
+ // ExecuteScalarAsync materialises datetime2 as DateTime with
+ // DateTimeKind.Unspecified; the boundary values are stored at
+ // UTC midnight by convention (migration seeds with 'T00:00:00'),
+ // so we re-tag the kind so downstream comparisons against
+ // DateTime.UtcNow stay in the same kind space.
+ var dt = (DateTime)raw;
+ return DateTime.SpecifyKind(dt, DateTimeKind.Utc);
+ }
+ finally
+ {
+ if (openedHere)
+ {
+ await conn.CloseAsync().ConfigureAwait(false);
+ }
+ }
+ }
+
+ ///
+ public async Task> EnsureLookaheadAsync(
+ int lookaheadMonths,
+ CancellationToken ct = default)
+ {
+ if (lookaheadMonths < 1)
+ {
+ throw new ArgumentOutOfRangeException(
+ nameof(lookaheadMonths),
+ lookaheadMonths,
+ "Lookahead must be at least one month — the partition function would otherwise be allowed to fall behind 'now'.");
+ }
+
+ var nowUtc = DateTime.UtcNow;
+ // Horizon: the FIRST-OF-MONTH that must be the strictly-greater-than
+ // max boundary after this call. Example: nowUtc = 2026-05-20 and
+ // lookaheadMonths = 1 → horizon = 2026-07-01 (so the partition for
+ // June 2026 is already in place by mid-May).
+ var horizon = NormalizeToFirstOfMonth(nowUtc).AddMonths(lookaheadMonths);
+
+ var max = await GetMaxBoundaryAsync(ct).ConfigureAwait(false);
+ if (max is null)
+ {
+ // No partition function (e.g. migrations not applied) — nothing
+ // we can safely SPLIT against. Log and return; the absence is a
+ // genuine misconfiguration that other parts of the system will
+ // surface louder than we could here.
+ _logger.LogWarning(
+ "EnsureLookaheadAsync: partition function {PartitionFunctionName} not found; skipping.",
+ PartitionFunctionName);
+ return Array.Empty();
+ }
+
+ // Start splitting from the FIRST month strictly after max — if max is
+ // already first-of-month (the common case), that's max + 1 month;
+ // otherwise NormalizeToFirstOfMonth rounds up.
+ var next = NormalizeToFirstOfMonth(max.Value.AddDays(1));
+
+ // Edge case: max already past horizon → no work to do.
+ if (next > horizon)
+ {
+ return Array.Empty();
+ }
+
+ var added = new List();
+ while (next <= horizon)
+ {
+ // Boundary literal must be a deterministic, culture-invariant ISO
+ // string — SQL Server parses it as datetime2 via implicit conversion.
+ // SPLIT RANGE does NOT accept @-parameters; the value is part of the
+ // DDL statement, so we render it directly. The format is
+ // guaranteed (yyyy-MM-ddTHH:mm:ss.fffffff) so there is no injection
+ // surface.
+ var literal = next.ToString("yyyy-MM-ddTHH:mm:ss.fffffff", CultureInfo.InvariantCulture);
+
+ // Before every SPLIT we must (re-)set the NEXT USED filegroup on
+ // ps_AuditLog_Month. Even though the scheme was created with
+ // `ALL TO ([PRIMARY])` (which auto-populates NEXT USED once), SQL
+ // Server consumes that hint on the FIRST split — subsequent splits
+ // raise msg 7707 ("partition scheme … does not have any next used
+ // filegroup") unless NEXT USED is explicitly re-set. Re-issuing it
+ // before every split is idempotent and keeps the loop simple.
+ var sql = $@"
+ALTER PARTITION SCHEME {PartitionSchemeName} NEXT USED [{TargetFileGroup}];
+ALTER PARTITION FUNCTION {PartitionFunctionName}() SPLIT RANGE ('{literal}');";
+
+ try
+ {
+ await _context.Database.ExecuteSqlRawAsync(sql, ct).ConfigureAwait(false);
+ added.Add(next);
+ }
+ catch (SqlException ex)
+ {
+ // Belt-and-braces: even though we read max-boundary first, an
+ // ALTER from another process could have raced us. Logging at
+ // Warning rather than Error because the desired end state
+ // (boundary present) is satisfied by either path.
+ _logger.LogWarning(
+ ex,
+ "EnsureLookaheadAsync: SPLIT RANGE for boundary {Boundary:o} failed; continuing.",
+ next);
+ }
+
+ next = NextMonthBoundary(next);
+ }
+
+ return added;
+ }
+
+ ///
+ /// Rounds an arbitrary instant UP to the next first-of-month UTC. Inputs
+ /// that ARE already a first-of-month at midnight are returned as-is so
+ /// callers can compose this freely without double-incrementing.
+ ///
+ private static DateTime NormalizeToFirstOfMonth(DateTime instant)
+ {
+ var utc = instant.Kind == DateTimeKind.Utc
+ ? instant
+ : DateTime.SpecifyKind(instant, DateTimeKind.Utc);
+
+ var firstOfThisMonth = new DateTime(utc.Year, utc.Month, 1, 0, 0, 0, DateTimeKind.Utc);
+ return utc == firstOfThisMonth ? firstOfThisMonth : firstOfThisMonth.AddMonths(1);
+ }
+
+ private static DateTime NextMonthBoundary(DateTime boundary) =>
+ boundary.AddMonths(1);
+}
diff --git a/src/ScadaLink.ConfigurationDatabase/Repositories/AuditLogRepository.cs b/src/ScadaLink.ConfigurationDatabase/Repositories/AuditLogRepository.cs
index d88271f..d2d74ac 100644
--- a/src/ScadaLink.ConfigurationDatabase/Repositories/AuditLogRepository.cs
+++ b/src/ScadaLink.ConfigurationDatabase/Repositories/AuditLogRepository.cs
@@ -179,18 +179,246 @@ VALUES
}
///
- /// M1 honest contract: throws . The
- /// UX_AuditLog_EventId unique index is non-aligned with
- /// ps_AuditLog_Month (it lives on [PRIMARY] to keep
- /// cheap), and SQL Server rejects
- /// ALTER TABLE … SWITCH PARTITION when a non-aligned index is present.
- /// The drop-and-rebuild dance that makes the switch legal ships with the M6
- /// purge actor.
+ /// M6-T4 production implementation of the drop-and-rebuild dance documented
+ /// on .
///
- public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default)
+ ///
+ ///
+ /// The staging table name is GUID-suffixed so concurrent purge attempts on
+ /// different boundaries cannot collide. The staging schema is byte-identical
+ /// to the live AuditLog table (same column types, lengths,
+ /// nullability, and clustered-key shape) — SQL Server's
+ /// ALTER TABLE … SWITCH PARTITION rejects any drift. Keep this CREATE
+ /// in sync with both the migration that ships the live table
+ /// (20260520142214_AddAuditLogTable) and
+ /// AuditLogEntityTypeConfiguration.
+ ///
+ ///
+ /// All five steps run inside an explicit transaction so the SWITCH +
+ /// staging-DROP are atomic from the perspective of a consumer reading via
+ /// snapshot isolation; the CATCH rolls back and runs an idempotent
+ /// "rebuild UX_AuditLog_EventId if it doesn't exist" so a partial failure
+ /// never leaves the live table without its idempotency-supporting unique
+ /// index.
+ ///
+ ///
+ public async Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default)
{
- throw new NotSupportedException(
- "AuditLog partition switch is blocked by the non-aligned UX_AuditLog_EventId " +
- "unique index; the drop-and-rebuild dance ships in M6 (purge actor).");
+ // GUID-suffixed staging name: prevents collision with any concurrent
+ // purge attempt and avoids polluting the AuditLog object namespace with
+ // a predictable identifier.
+ var stagingTableName = $"AuditLog_Staging_{Guid.NewGuid():N}";
+
+ // ISO 8601 in UTC — SQL Server's datetime2 literal parser accepts this
+ // unambiguously and the value is round-trip-safe across SET DATEFORMAT
+ // settings.
+ var monthBoundaryStr = monthBoundary.ToUniversalTime().ToString("yyyy-MM-dd HH:mm:ss");
+
+ // Two-statement batch: the first SELECT samples the per-partition row
+ // count BEFORE the dance so we can report it back to the purge actor;
+ // the second batch performs the drop-and-rebuild. We use OUTPUT-style
+ // variables wired through @@ROWCOUNT after the SWITCH is not viable
+ // because SWITCH is a metadata-only operation that doesn't move rows in
+ // a way @@ROWCOUNT can observe.
+ var sampleSql = $@"
+ SELECT COUNT_BIG(*) FROM dbo.AuditLog
+ WHERE $PARTITION.pf_AuditLog_Month(OccurredAtUtc) =
+ $partition.pf_AuditLog_Month('{monthBoundaryStr}');";
+
+ var sql = $@"
+ BEGIN TRY
+ BEGIN TRANSACTION;
+
+ -- 1. Drop the non-aligned unique index. ALTER TABLE SWITCH refuses
+ -- to run while it exists.
+ IF EXISTS (SELECT 1 FROM sys.indexes WHERE name = 'UX_AuditLog_EventId' AND object_id = OBJECT_ID('dbo.AuditLog'))
+ DROP INDEX UX_AuditLog_EventId ON dbo.AuditLog;
+
+ -- 2. Staging table on [PRIMARY] (non-partitioned) with column shapes
+ -- byte-identical to dbo.AuditLog. Any drift here causes SWITCH to
+ -- reject the operation with msg 4904/4915.
+ CREATE TABLE dbo.[{stagingTableName}] (
+ EventId uniqueidentifier NOT NULL,
+ OccurredAtUtc datetime2(7) NOT NULL,
+ IngestedAtUtc datetime2(7) NULL,
+ Channel varchar(32) NOT NULL,
+ Kind varchar(32) NOT NULL,
+ CorrelationId uniqueidentifier NULL,
+ SourceSiteId varchar(64) NULL,
+ SourceInstanceId varchar(128) NULL,
+ SourceScript varchar(128) NULL,
+ Actor varchar(128) NULL,
+ Target varchar(256) NULL,
+ Status varchar(32) NOT NULL,
+ HttpStatus int NULL,
+ DurationMs int NULL,
+ ErrorMessage nvarchar(1024) NULL,
+ ErrorDetail nvarchar(max) NULL,
+ RequestSummary nvarchar(max) NULL,
+ ResponseSummary nvarchar(max) NULL,
+ PayloadTruncated bit NOT NULL,
+ Extra nvarchar(max) NULL,
+ ForwardState varchar(32) NULL,
+ CONSTRAINT PK_{stagingTableName} PRIMARY KEY CLUSTERED (EventId, OccurredAtUtc)
+ ) ON [PRIMARY];
+
+ -- 3. Switch the partition out. $partition.pf_AuditLog_Month returns
+ -- the partition number that contains the supplied boundary value;
+ -- SWITCH PARTITION N moves that partition's pages to the staging
+ -- table (metadata-only, no row copying).
+ DECLARE @partitionNumber int = $partition.pf_AuditLog_Month('{monthBoundaryStr}');
+ DECLARE @sql nvarchar(max) = 'ALTER TABLE dbo.AuditLog SWITCH PARTITION ' + CAST(@partitionNumber AS nvarchar(10)) + ' TO dbo.[{stagingTableName}];';
+ EXEC sp_executesql @sql;
+
+ -- 4. Drop staging — the rows are discarded here. This is the purge.
+ DROP TABLE dbo.[{stagingTableName}];
+
+ -- 5. Rebuild the non-aligned unique index. Live traffic that hit the
+ -- table during steps 1-4 saw composite-PK uniqueness only; from
+ -- here on, single-column EventId uniqueness is restored.
+ CREATE UNIQUE NONCLUSTERED INDEX UX_AuditLog_EventId ON dbo.AuditLog (EventId) ON [PRIMARY];
+
+ COMMIT TRANSACTION;
+ END TRY
+ BEGIN CATCH
+ IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION;
+
+ -- Best-effort staging cleanup. The DROP INDEX in step 1 is now
+ -- rolled back (so the index is back), but the staging table from
+ -- step 2 may or may not survive the rollback depending on the
+ -- failure point. Guard the DROP so a missing staging table doesn't
+ -- mask the original error.
+ IF OBJECT_ID('dbo.[{stagingTableName}]', 'U') IS NOT NULL DROP TABLE dbo.[{stagingTableName}];
+
+ -- Idempotent index rebuild — covers the niche case where ROLLBACK
+ -- failed to restore UX_AuditLog_EventId (or the failure happened
+ -- AFTER the COMMIT, which shouldn't be possible inside this TRY
+ -- but is cheap insurance). Without this, a failed switch could
+ -- leave the live table without its idempotency-supporting index.
+ IF NOT EXISTS (SELECT 1 FROM sys.indexes WHERE name = 'UX_AuditLog_EventId' AND object_id = OBJECT_ID('dbo.AuditLog'))
+ CREATE UNIQUE NONCLUSTERED INDEX UX_AuditLog_EventId ON dbo.AuditLog (EventId) ON [PRIMARY];
+
+ -- Surface the original error to the caller — the purge actor logs
+ -- and continues with the next boundary.
+ THROW;
+ END CATCH;";
+
+ // Sample the row count before the switch. The sample is best-effort
+ // (no transaction wrapping the sample-then-switch pair) because the
+ // central singleton is the only writer to this RPC and a daily-purge
+ // tick doesn't compete with concurrent SwitchOut callers. A
+ // concurrent INSERT racing the sample under-reports by at most a
+ // few rows, which is acceptable for an "approximate" purged-row
+ // count surfaced via AuditLogPurgedEvent.
+ long rowsDeleted = 0;
+ var conn = _context.Database.GetDbConnection();
+ var openedHere = false;
+ if (conn.State != System.Data.ConnectionState.Open)
+ {
+ await conn.OpenAsync(ct).ConfigureAwait(false);
+ openedHere = true;
+ }
+ try
+ {
+ await using (var sampleCmd = conn.CreateCommand())
+ {
+ sampleCmd.CommandText = sampleSql;
+ var sampleResult = await sampleCmd.ExecuteScalarAsync(ct).ConfigureAwait(false);
+ if (sampleResult is not null && sampleResult is not DBNull)
+ {
+ rowsDeleted = Convert.ToInt64(sampleResult);
+ }
+ }
+ }
+ finally
+ {
+ if (openedHere)
+ {
+ await conn.CloseAsync().ConfigureAwait(false);
+ }
+ }
+
+ await _context.Database.ExecuteSqlRawAsync(sql, ct);
+ return rowsDeleted;
+ }
+
+ ///
+ /// Returns the set of pf_AuditLog_Month boundaries whose partition's
+ /// MAX(OccurredAtUtc) is strictly older than .
+ /// Boundaries with empty partitions are excluded — purging an empty
+ /// partition is wasted I/O.
+ ///
+ ///
+ ///
+ /// The CTE pulls every boundary value defined by the partition function and
+ /// joins it (via $PARTITION.pf_AuditLog_Month) to the live AuditLog
+ /// to compute per-partition MAX(OccurredAtUtc). The outer filter
+ /// keeps only those whose MAX is non-NULL (partition has rows) AND strictly
+ /// less than the threshold (every row is past retention).
+ ///
+ ///
+ /// Note: the query scans the live OccurredAtUtc column to compute
+ /// the MAX per partition. With IX_AuditLog_OccurredAtUtc on the
+ /// partition-aligned scheme this is a single index seek per partition; for
+ /// 24 partitions and a daily purge cadence the cost is negligible.
+ ///
+ ///
+ public async Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold,
+ CancellationToken ct = default)
+ {
+ var thresholdUtc = threshold.ToUniversalTime();
+ var thresholdStr = thresholdUtc.ToString("yyyy-MM-dd HH:mm:ss.fffffff");
+
+ // Per-partition MAX over the live table. We materialise the boundary
+ // list first (24 rows) then LEFT JOIN to the MAX aggregate so empty
+ // partitions surface as NULL and get filtered out by the WHERE clause.
+ var sql = $@"
+ WITH Boundaries AS (
+ SELECT CAST(rv.value AS datetime2(7)) AS BoundaryValue,
+ rv.boundary_id AS BoundaryId
+ FROM sys.partition_range_values rv
+ INNER JOIN sys.partition_functions pf ON rv.function_id = pf.function_id
+ WHERE pf.name = 'pf_AuditLog_Month'
+ )
+ SELECT b.BoundaryValue
+ FROM Boundaries b
+ CROSS APPLY (
+ SELECT MAX(a.OccurredAtUtc) AS MaxOccurredAt
+ FROM dbo.AuditLog a
+ WHERE $PARTITION.pf_AuditLog_Month(a.OccurredAtUtc) = b.BoundaryId + 1
+ ) x
+ WHERE x.MaxOccurredAt IS NOT NULL
+ AND x.MaxOccurredAt < CAST('{thresholdStr}' AS datetime2(7))
+ ORDER BY b.BoundaryValue;";
+
+ var conn = _context.Database.GetDbConnection();
+ var openedHere = false;
+ if (conn.State != System.Data.ConnectionState.Open)
+ {
+ await conn.OpenAsync(ct).ConfigureAwait(false);
+ openedHere = true;
+ }
+
+ var results = new List();
+ try
+ {
+ await using var cmd = conn.CreateCommand();
+ cmd.CommandText = sql;
+ await using var reader = await cmd.ExecuteReaderAsync(ct).ConfigureAwait(false);
+ while (await reader.ReadAsync(ct).ConfigureAwait(false))
+ {
+ results.Add(reader.GetDateTime(0));
+ }
+ }
+ finally
+ {
+ if (openedHere)
+ {
+ await conn.CloseAsync().ConfigureAwait(false);
+ }
+ }
+
+ return results;
}
}
diff --git a/src/ScadaLink.ConfigurationDatabase/ServiceCollectionExtensions.cs b/src/ScadaLink.ConfigurationDatabase/ServiceCollectionExtensions.cs
index bf79b29..d926f1e 100644
--- a/src/ScadaLink.ConfigurationDatabase/ServiceCollectionExtensions.cs
+++ b/src/ScadaLink.ConfigurationDatabase/ServiceCollectionExtensions.cs
@@ -1,8 +1,10 @@
using Microsoft.AspNetCore.DataProtection;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
+using ScadaLink.Commons.Interfaces;
using ScadaLink.Commons.Interfaces.Repositories;
using ScadaLink.Commons.Interfaces.Services;
+using ScadaLink.ConfigurationDatabase.Maintenance;
using ScadaLink.ConfigurationDatabase.Repositories;
using ScadaLink.ConfigurationDatabase.Services;
@@ -52,6 +54,13 @@ public static class ServiceCollectionExtensions
services.AddScoped();
services.AddScoped();
+ // #23 M6 Bundle D: IPartitionMaintenance drives the daily roll-forward
+ // of pf_AuditLog_Month from the central AuditLogPartitionMaintenanceService
+ // hosted service. Scoped because the implementation reuses the per-scope
+ // ScadaLinkDbContext for raw-SQL execution; the hosted service opens a
+ // fresh scope on each tick (mirrors AuditLogPurgeActor / AuditLogIngestActor).
+ services.AddScoped();
+
services.AddDataProtection()
.PersistKeysToDbContext();
diff --git a/src/ScadaLink.HealthMonitoring/ISiteHealthCollector.cs b/src/ScadaLink.HealthMonitoring/ISiteHealthCollector.cs
index bcd5f9e..a1ca37b 100644
--- a/src/ScadaLink.HealthMonitoring/ISiteHealthCollector.cs
+++ b/src/ScadaLink.HealthMonitoring/ISiteHealthCollector.cs
@@ -1,4 +1,5 @@
using ScadaLink.Commons.Messages.Health;
+using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
namespace ScadaLink.HealthMonitoring;
@@ -28,6 +29,15 @@ public interface ISiteHealthCollector
/// AddAuditLogHealthMetricsBridge().
///
void IncrementAuditRedactionFailure();
+ ///
+ /// Audit Log (#23) M6 Bundle E (T6) — replace the latest site-local
+ /// audit-queue backlog snapshot (pending count, oldest pending row,
+ /// on-disk file bytes) used by the next call.
+ /// Refreshed periodically by the SiteAuditBacklogReporter hosted
+ /// service so each report carries a recent point-in-time view of the
+ /// site→central drain health.
+ ///
+ void UpdateSiteAuditBacklog(SiteAuditBacklogSnapshot snapshot);
void UpdateConnectionHealth(string connectionName, ConnectionHealth health);
void RemoveConnection(string connectionName);
void UpdateTagResolution(string connectionName, int totalSubscribed, int successfullyResolved);
diff --git a/src/ScadaLink.HealthMonitoring/SiteHealthCollector.cs b/src/ScadaLink.HealthMonitoring/SiteHealthCollector.cs
index 47567c9..6f55061 100644
--- a/src/ScadaLink.HealthMonitoring/SiteHealthCollector.cs
+++ b/src/ScadaLink.HealthMonitoring/SiteHealthCollector.cs
@@ -1,5 +1,6 @@
using System.Collections.Concurrent;
using ScadaLink.Commons.Messages.Health;
+using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
namespace ScadaLink.HealthMonitoring;
@@ -15,6 +16,7 @@ public class SiteHealthCollector : ISiteHealthCollector
private int _deadLetterCount;
private int _siteAuditWriteFailures;
private int _auditRedactionFailures;
+ private volatile SiteAuditBacklogSnapshot? _siteAuditBacklog;
private readonly ConcurrentDictionary _connectionStatuses = new();
private readonly ConcurrentDictionary _tagResolutionCounts = new();
private readonly ConcurrentDictionary _connectionEndpoints = new();
@@ -89,6 +91,18 @@ public class SiteHealthCollector : ISiteHealthCollector
Interlocked.Increment(ref _auditRedactionFailures);
}
+ ///
+ /// Audit Log (#23) M6 Bundle E (T6) — replace the latest backlog snapshot
+ /// from the site SQLite writer. The field is a single reference write
+ /// (volatile) so the next sees the most recent
+ /// snapshot — there is no count to reset, the report just carries forward
+ /// whatever was last refreshed.
+ ///
+ public void UpdateSiteAuditBacklog(SiteAuditBacklogSnapshot snapshot)
+ {
+ _siteAuditBacklog = snapshot ?? throw new ArgumentNullException(nameof(snapshot));
+ }
+
///
/// Update the health status for a named data connection.
/// Called by DCL when connection state changes.
@@ -207,6 +221,7 @@ public class SiteHealthCollector : ISiteHealthCollector
ParkedMessageCount: Interlocked.CompareExchange(ref _parkedMessageCount, 0, 0),
ClusterNodes: _clusterNodes?.ToList(),
SiteAuditWriteFailures: siteAuditWriteFailures,
- AuditRedactionFailure: auditRedactionFailures);
+ AuditRedactionFailure: auditRedactionFailures,
+ SiteAuditBacklog: _siteAuditBacklog);
}
}
diff --git a/src/ScadaLink.Host/Actors/AkkaHostedService.cs b/src/ScadaLink.Host/Actors/AkkaHostedService.cs
index b8c5171..dce065a 100644
--- a/src/ScadaLink.Host/Actors/AkkaHostedService.cs
+++ b/src/ScadaLink.Host/Actors/AkkaHostedService.cs
@@ -34,6 +34,13 @@ public class AkkaHostedService : IHostedService
private readonly CommunicationOptions _communicationOptions;
private readonly ILogger _logger;
private ActorSystem? _actorSystem;
+ ///
+ /// Auxiliary IDisposables (e.g. the SiteAuditTelemetryStalledTracker)
+ /// that this hosted service constructs at start time and must tear down
+ /// on shutdown — they don't fit the ActorSystem lifecycle but share its
+ /// process scope.
+ ///
+ private readonly List _trackedDisposables = new();
public AkkaHostedService(
IServiceProvider serviceProvider,
@@ -201,6 +208,31 @@ akka {{
public async Task StopAsync(CancellationToken cancellationToken)
{
+ // Dispose auxiliary subscribers (e.g. SiteAuditTelemetryStalledTracker)
+ // BEFORE Akka shuts down so their EventStream unsubscribe calls run
+ // while the system is still alive. Per-tracker Dispose is wrapped in
+ // its own try so a misbehaving subscriber can't sink the shutdown.
+ // Snapshot the list inside a lock so a concurrent StartAsync (the
+ // test harness sometimes triggers a second start/stop interleaving)
+ // can't race the enumeration. Clearing the original list under the
+ // same lock leaves the next StartAsync with a clean slate.
+ IDisposable[] disposables;
+ lock (_trackedDisposables)
+ {
+ disposables = _trackedDisposables.ToArray();
+ _trackedDisposables.Clear();
+ }
+ foreach (var disposable in disposables)
+ {
+ try { disposable.Dispose(); }
+ catch (Exception ex)
+ {
+ _logger.LogWarning(ex,
+ "Auxiliary subscriber {Type} threw during shutdown",
+ disposable.GetType().Name);
+ }
+ }
+
if (_actorSystem != null)
{
_logger.LogInformation("Shutting down Akka.NET actor system via CoordinatedShutdown...");
@@ -349,6 +381,31 @@ akka {{
"AuditLogIngestActor singleton created (gRPC server bound: {GrpcBound})",
grpcServer is not null);
+ // Audit Log (#23) M6 Bundle E (T7): subscribe the per-site stalled
+ // telemetry tracker to the actor system EventStream NOW that the
+ // system exists. The tracker mirrors every
+ // SiteAuditTelemetryStalledChanged publication (from
+ // SiteAuditReconciliationActor — wired in a later bundle) into the
+ // AuditCentralHealthSnapshot singleton so the central health surface
+ // sees per-site stalled state. The tracker is constructed here rather
+ // than in AddAuditLogCentralMaintenance because its ctor needs an
+ // ActorSystem, which is not a DI-resolvable singleton — it's owned
+ // by this hosted service. The snapshot singleton is resolvable;
+ // passing it in seeds the tracker's Apply() so both internal state
+ // and the snapshot stay in lock-step.
+ var auditCentralSnapshot = _serviceProvider
+ .GetService();
+ if (auditCentralSnapshot is not null)
+ {
+ var stalledTracker = new ScadaLink.AuditLog.Central.SiteAuditTelemetryStalledTracker(
+ _actorSystem!, auditCentralSnapshot);
+ lock (_trackedDisposables)
+ {
+ _trackedDisposables.Add(stalledTracker);
+ }
+ _logger.LogInformation("SiteAuditTelemetryStalledTracker subscribed to EventStream");
+ }
+
// Site Call Audit (#22) — central singleton mirrors the AuditLogIngest
// and NotificationOutbox patterns. M3's dual-write transaction routes
// SiteCalls upserts through AuditLogIngestActor's own scope-per-message
@@ -605,7 +662,7 @@ akka {{
var siteAuditOptions = _serviceProvider
.GetRequiredService>();
var siteAuditQueue = _serviceProvider
- .GetRequiredService();
+ .GetRequiredService();
var siteAuditClient = _serviceProvider
.GetRequiredService();
var siteAuditLogger = _serviceProvider.GetRequiredService()
@@ -640,6 +697,13 @@ akka {{
// handshake has completed". Streams opened before SetReady are already
// rejected by SiteStreamGrpcServer with StatusCode.Unavailable.
var grpcServer = _serviceProvider.GetService();
+ // Audit Log (#23 M6): hand the site-local SqliteAuditWriter (which
+ // implements ISiteAuditQueue) to the gRPC server so the PullAuditEvents
+ // reconciliation RPC can serve central's pulls. Both the writer and the
+ // gRPC server are singletons — wiring this here keeps the dependency
+ // direction one-way (Host knows both; Communication doesn't reach back
+ // into AuditLog).
+ grpcServer?.SetSiteAuditQueue(siteAuditQueue);
grpcServer?.SetReady(_actorSystem!);
}
}
diff --git a/src/ScadaLink.Host/Program.cs b/src/ScadaLink.Host/Program.cs
index b1119d1..3632824 100644
--- a/src/ScadaLink.Host/Program.cs
+++ b/src/ScadaLink.Host/Program.cs
@@ -84,6 +84,10 @@ try
// IAuditLogRepository. The site writer chain is still registered (lazy
// singletons) but is never resolved on a central node.
builder.Services.AddAuditLog(builder.Configuration);
+ // #23 M6-T5 Bundle D — central-only hosted service that rolls
+ // pf_AuditLog_Month forward monthly. Depends on IPartitionMaintenance
+ // (registered below by AddConfigurationDatabase).
+ builder.Services.AddAuditLogCentralMaintenance(builder.Configuration);
// Site Call Audit (#22) — central node owns the SiteCallAuditActor
// singleton (M3 Bundle F). The extension itself currently registers
// nothing — actor Props are constructed inline in AkkaHostedService —
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/AuditLogIngestActorTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogIngestActorTests.cs
index 36de05f..724ae68 100644
--- a/tests/ScadaLink.AuditLog.Tests/Central/AuditLogIngestActorTests.cs
+++ b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogIngestActorTests.cs
@@ -214,7 +214,11 @@ public class AuditLogIngestActorTests : TestKit, IClassFixture
_inner.QueryAsync(filter, paging, ct);
- public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default) =>
+ public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default) =>
_inner.SwitchOutPartitionAsync(monthBoundary, ct);
+
+ public Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold, CancellationToken ct = default) =>
+ _inner.GetPartitionBoundariesOlderThanAsync(threshold, ct);
}
}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPartitionMaintenanceServiceTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPartitionMaintenanceServiceTests.cs
new file mode 100644
index 0000000..4e65207
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPartitionMaintenanceServiceTests.cs
@@ -0,0 +1,154 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.Commons.Interfaces;
+using Xunit;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle D (#23 M6-T5) tests for .
+/// All tests use an in-memory stub —
+/// the real EF/MSSQL implementation is exercised by the
+/// AuditLogPartitionMaintenanceTests integration suite in
+/// ScadaLink.ConfigurationDatabase.Tests. This file is purely
+/// about the hosted service's policy decisions (start/stop, exception
+/// containment).
+///
+public class AuditLogPartitionMaintenanceServiceTests
+{
+ ///
+ /// Recording stub — counts EnsureLookaheadAsync invocations and lets the
+ /// test inject an exception per invocation to drive the catch-all path.
+ ///
+ private sealed class RecordingMaintenance : IPartitionMaintenance
+ {
+ public int EnsureCallCount;
+ public Exception? ThrowOnce;
+
+ public Task> EnsureLookaheadAsync(int lookaheadMonths, CancellationToken ct = default)
+ {
+ Interlocked.Increment(ref EnsureCallCount);
+ if (ThrowOnce is { } ex)
+ {
+ ThrowOnce = null;
+ throw ex;
+ }
+ return Task.FromResult>(Array.Empty());
+ }
+
+ public Task GetMaxBoundaryAsync(CancellationToken ct = default) =>
+ Task.FromResult(DateTime.UtcNow.AddMonths(6));
+ }
+
+ ///
+ /// Captures logged exceptions so the catch-all assertion can prove
+ /// the exception was actually logged (not silently swallowed) and was
+ /// the exact instance the stub threw.
+ ///
+ private sealed class CapturingLogger : ILogger
+ {
+ public List<(LogLevel Level, Exception? Exception, string Message)> Entries { get; } = new();
+
+ public IDisposable? BeginScope(TState state) where TState : notnull => null;
+
+ public bool IsEnabled(LogLevel logLevel) => true;
+
+ public void Log(
+ LogLevel logLevel,
+ EventId eventId,
+ TState state,
+ Exception? exception,
+ Func formatter)
+ {
+ Entries.Add((logLevel, exception, formatter(state, exception)));
+ }
+ }
+
+ private static IServiceProvider BuildProvider(IPartitionMaintenance maintenance)
+ {
+ var services = new ServiceCollection();
+ // IPartitionMaintenance is registered as scoped by AddConfigurationDatabase;
+ // we mirror that here so the hosted service's CreateAsyncScope +
+ // GetRequiredService resolves the stub the test injected.
+ services.AddScoped(_ => maintenance);
+ return services.BuildServiceProvider();
+ }
+
+ [Fact]
+ public async Task StartStop_NoExceptions()
+ {
+ // Long interval so only the eager startup tick fires inside the test
+ // window — keeps assertions deterministic without relying on
+ // multiple cadence loops.
+ var opts = Options.Create(new AuditLogPartitionMaintenanceOptions
+ {
+ IntervalSeconds = 60,
+ LookaheadMonths = 1,
+ });
+ var maintenance = new RecordingMaintenance();
+ var sp = BuildProvider(maintenance);
+
+ var svc = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ NullLogger.Instance);
+
+ await svc.StartAsync(CancellationToken.None);
+
+ // Spin briefly until the startup tick has fired — the loop's first
+ // SafeMaintainAsync runs on a background Task.Run continuation, so
+ // we can't synchronously rely on its completion.
+ var deadline = DateTime.UtcNow.AddSeconds(3);
+ while (Volatile.Read(ref maintenance.EnsureCallCount) < 1 && DateTime.UtcNow < deadline)
+ {
+ await Task.Delay(20);
+ }
+
+ await svc.StopAsync(CancellationToken.None);
+ svc.Dispose();
+
+ Assert.True(maintenance.EnsureCallCount >= 1, $"expected at least 1 ensure call, got {maintenance.EnsureCallCount}");
+ }
+
+ [Fact]
+ public async Task SafeMaintain_ExceptionLogged_NotPropagated()
+ {
+ var opts = Options.Create(new AuditLogPartitionMaintenanceOptions
+ {
+ IntervalSeconds = 60,
+ LookaheadMonths = 1,
+ });
+ // The injected exception fires on the FIRST EnsureLookaheadAsync call
+ // (the startup tick) — the hosted service must contain it and
+ // continue running.
+ var boom = new InvalidOperationException("simulated maintenance failure");
+ var maintenance = new RecordingMaintenance { ThrowOnce = boom };
+ var sp = BuildProvider(maintenance);
+ var logger = new CapturingLogger();
+
+ var svc = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ logger);
+
+ // StartAsync must not throw even though the very first tick will fail.
+ await svc.StartAsync(CancellationToken.None);
+
+ // Wait for the error to surface in the logger.
+ var deadline = DateTime.UtcNow.AddSeconds(3);
+ while (!logger.Entries.Any(e => e.Exception == boom) && DateTime.UtcNow < deadline)
+ {
+ await Task.Delay(20);
+ }
+
+ await svc.StopAsync(CancellationToken.None);
+ svc.Dispose();
+
+ var errorEntry = Assert.Single(logger.Entries, e => e.Exception == boom);
+ Assert.Equal(LogLevel.Error, errorEntry.Level);
+ Assert.Equal(1, maintenance.EnsureCallCount);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPurgeActorTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPurgeActorTests.cs
new file mode 100644
index 0000000..afa20bf
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/AuditLogPurgeActorTests.cs
@@ -0,0 +1,376 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.AuditLog.Configuration;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Types.Audit;
+using ScadaLink.Commons.Types.Enums;
+using ScadaLink.ConfigurationDatabase;
+using ScadaLink.ConfigurationDatabase.Repositories;
+using ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle C (#23 M6-T4) tests for . The fast,
+/// schedule-only tests substitute a recording stub for
+/// so the timer + per-boundary error-isolation
+/// + event-publish machinery can be exercised without an MSSQL container.
+/// The end-to-end "real partition gets switched out" assertion lives in the
+/// repository tests (Bundle C of M6-T4); this actor file is purely about the
+/// actor's policy decisions.
+///
+public class AuditLogPurgeActorTests : TestKit, IClassFixture
+{
+ private readonly MsSqlMigrationFixture _fixture;
+
+ public AuditLogPurgeActorTests(MsSqlMigrationFixture fixture)
+ {
+ _fixture = fixture;
+ }
+
+ ///
+ /// In-memory recording stub. Captures every
+ /// + every
+ /// so tests can assert which boundaries
+ /// the actor chose to purge and how many ticks it issued. Also lets a
+ /// specific boundary be configured to throw so the continue-on-error path
+ /// is exercisable.
+ ///
+ private sealed class RecordingRepo : IAuditLogRepository
+ {
+ public List ThresholdQueries { get; } = new();
+ public List SwitchedBoundaries { get; } = new();
+ public Func RowsPerBoundary { get; set; } = _ => 0L;
+ public DateTime? ThrowOnBoundary { get; set; }
+ public Exception? BoundaryException { get; set; }
+
+ // The actor enumerator returns whichever list is configured here.
+ // Mutating this between ticks lets tests simulate "no longer
+ // eligible" boundaries on the second tick.
+ public List Boundaries { get; set; } = new();
+
+ public Task InsertIfNotExistsAsync(AuditEvent evt, CancellationToken ct = default) =>
+ Task.CompletedTask;
+
+ public Task> QueryAsync(
+ AuditLogQueryFilter filter, AuditLogPaging paging, CancellationToken ct = default) =>
+ Task.FromResult>(Array.Empty());
+
+ public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default)
+ {
+ if (ThrowOnBoundary.HasValue && monthBoundary == ThrowOnBoundary.Value)
+ {
+ throw BoundaryException ?? new InvalidOperationException("simulated switch failure");
+ }
+ SwitchedBoundaries.Add(monthBoundary);
+ return Task.FromResult(RowsPerBoundary(monthBoundary));
+ }
+
+ public Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold, CancellationToken ct = default)
+ {
+ ThresholdQueries.Add(threshold);
+ return Task.FromResult>(Boundaries.ToArray());
+ }
+ }
+
+ private IServiceProvider BuildScopedProvider(IAuditLogRepository repo)
+ {
+ var services = new ServiceCollection();
+ // Mirror AddConfigurationDatabase: IAuditLogRepository is scoped, so
+ // the actor opens a fresh scope per tick and resolves there.
+ services.AddScoped(_ => repo);
+ return services.BuildServiceProvider();
+ }
+
+ private IActorRef CreateActor(
+ IAuditLogRepository repo,
+ AuditLogPurgeOptions purgeOptions,
+ AuditLogOptions? auditOptions = null)
+ {
+ var sp = BuildScopedProvider(repo);
+ return Sys.ActorOf(Props.Create(() => new AuditLogPurgeActor(
+ sp,
+ Options.Create(purgeOptions),
+ Options.Create(auditOptions ?? new AuditLogOptions()),
+ NullLogger.Instance)));
+ }
+
+ private static AuditLogPurgeOptions FastTickOptions(TimeSpan? interval = null) => new()
+ {
+ IntervalHours = 24,
+ IntervalOverride = interval ?? TimeSpan.FromMilliseconds(100),
+ };
+
+ ///
+ /// Subscribe a probe to the EventStream so the test can observe
+ /// publications synchronously.
+ ///
+ private Akka.TestKit.TestProbe SubscribePurged()
+ {
+ var probe = CreateTestProbe();
+ Sys.EventStream.Subscribe(probe.Ref, typeof(AuditLogPurgedEvent));
+ return probe;
+ }
+
+ // ---------------------------------------------------------------------
+ // 1. Tick_Fires_OnDailyInterval
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_Fires_OnDailyInterval()
+ {
+ var repo = new RecordingRepo();
+ CreateActor(repo, FastTickOptions());
+
+ // The first scheduled tick fires after the configured interval. We
+ // assert the visible side effect (the enumerator was called) rather
+ // than racing on internal state.
+ AwaitAssert(
+ () => Assert.True(repo.ThresholdQueries.Count >= 1,
+ $"expected >= 1 enumerator call, got {repo.ThresholdQueries.Count}"),
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 2. Tick_OldPartitions_SwitchedOut
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_OldPartitions_SwitchedOut()
+ {
+ var repo = new RecordingRepo
+ {
+ Boundaries = new List
+ {
+ new(2025, 11, 1, 0, 0, 0, DateTimeKind.Utc),
+ new(2025, 12, 1, 0, 0, 0, DateTimeKind.Utc),
+ },
+ RowsPerBoundary = _ => 42L,
+ };
+
+ CreateActor(repo, FastTickOptions());
+
+ AwaitAssert(
+ () =>
+ {
+ Assert.Contains(new DateTime(2025, 11, 1, 0, 0, 0, DateTimeKind.Utc), repo.SwitchedBoundaries);
+ Assert.Contains(new DateTime(2025, 12, 1, 0, 0, 0, DateTimeKind.Utc), repo.SwitchedBoundaries);
+ },
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 3. Tick_NewerPartitions_Untouched
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_NewerPartitions_Untouched()
+ {
+ // The actor's contract: it only touches whatever the enumerator
+ // returns. The enumerator (in production) filters out non-eligible
+ // boundaries; here we simulate that by handing back an empty list
+ // and asserting the actor switched nothing despite the tick firing.
+ var repo = new RecordingRepo { Boundaries = new List() };
+
+ CreateActor(repo, FastTickOptions());
+
+ // Wait for at least one tick (visible via the enumerator call) then
+ // assert no switch happened.
+ AwaitAssert(
+ () => Assert.True(repo.ThresholdQueries.Count >= 1),
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+
+ Assert.Empty(repo.SwitchedBoundaries);
+ }
+
+ // ---------------------------------------------------------------------
+ // 4. Tick_PublishesPurgedEvent_WithRowCount
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_PublishesPurgedEvent_WithRowCount()
+ {
+ var boundary = new DateTime(2025, 6, 1, 0, 0, 0, DateTimeKind.Utc);
+ var repo = new RecordingRepo
+ {
+ Boundaries = new List { boundary },
+ RowsPerBoundary = _ => 1234L,
+ };
+
+ var probe = SubscribePurged();
+ CreateActor(repo, FastTickOptions());
+
+ var msg = probe.ExpectMsg(TimeSpan.FromSeconds(5));
+ Assert.Equal(boundary, msg.MonthBoundary);
+ Assert.Equal(1234L, msg.RowsDeleted);
+ Assert.True(msg.DurationMs >= 0,
+ $"DurationMs should be non-negative; was {msg.DurationMs}");
+ }
+
+ // ---------------------------------------------------------------------
+ // 5. Tick_SwitchThrows_OtherPartitionsStillProcessed (continue-on-error)
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_SwitchThrows_OtherPartitionsStillProcessed()
+ {
+ var poisonBoundary = new DateTime(2025, 7, 1, 0, 0, 0, DateTimeKind.Utc);
+ var goodBoundary = new DateTime(2025, 8, 1, 0, 0, 0, DateTimeKind.Utc);
+ var repo = new RecordingRepo
+ {
+ Boundaries = new List { poisonBoundary, goodBoundary },
+ ThrowOnBoundary = poisonBoundary,
+ BoundaryException = new InvalidOperationException("simulated switch failure for poison boundary"),
+ };
+
+ CreateActor(repo, FastTickOptions());
+
+ AwaitAssert(
+ () =>
+ {
+ // The good boundary was still switched even though the poison
+ // boundary threw.
+ Assert.Contains(goodBoundary, repo.SwitchedBoundaries);
+ Assert.DoesNotContain(poisonBoundary, repo.SwitchedBoundaries);
+ },
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 6. EndToEnd_RealPartition_RowsRemoved_PurgedEventPublished
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_RealPartition_RowsRemoved_PurgedEventPublished()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ // Today is ~2026-05-20 per the test environment. With RetentionDays =
+ // 60 the actor computes threshold ≈ 2026-03-21:
+ // * Jan partition (MAX = Jan 15) → older than threshold → PURGED
+ // * Apr partition (MAX = Apr 15) → newer than threshold → KEPT
+ var siteId = "purge-e2e-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var janEvt = new AuditEvent
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = new DateTime(2026, 1, 15, 0, 0, 0, DateTimeKind.Utc),
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ SourceSiteId = siteId,
+ };
+ var aprEvt = new AuditEvent
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = new DateTime(2026, 4, 15, 0, 0, 0, DateTimeKind.Utc),
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ SourceSiteId = siteId,
+ };
+
+ await using (var seedContext = CreateMsSqlContext())
+ {
+ var seedRepo = new AuditLogRepository(seedContext);
+ await seedRepo.InsertIfNotExistsAsync(janEvt);
+ await seedRepo.InsertIfNotExistsAsync(aprEvt);
+ }
+
+ // Wire the actor's DI scope to the real repository against the
+ // fixture's MSSQL database. The actor opens a fresh scope per tick,
+ // so register the context as scoped (mirroring the production
+ // AddConfigurationDatabase wiring).
+ var services = new ServiceCollection();
+ services.AddDbContext(
+ opts => opts.UseSqlServer(_fixture.ConnectionString),
+ ServiceLifetime.Scoped);
+ services.AddScoped();
+ var sp = services.BuildServiceProvider();
+
+ var auditOptions = new AuditLogOptions { RetentionDays = 60 };
+ var purgeOptions = new AuditLogPurgeOptions
+ {
+ IntervalHours = 24,
+ IntervalOverride = TimeSpan.FromMilliseconds(100),
+ };
+
+ var probe = SubscribePurged();
+ Sys.ActorOf(Props.Create(() => new AuditLogPurgeActor(
+ sp,
+ Options.Create(purgeOptions),
+ Options.Create(auditOptions),
+ NullLogger.Instance)));
+
+ // The probe receives one AuditLogPurgedEvent per partition the actor
+ // purges per tick — other test runs that share the fixture DB may
+ // also leave behind eligible partitions, but this test creates its
+ // own fixture DB so the Jan-2026 partition is the only eligible one.
+ // Use FishForMessage to filter just in case, with a generous timeout
+ // because the real drop-and-rebuild dance against MSSQL routinely
+ // takes a couple of seconds on a busy dev container.
+ var janBoundary = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+ var matched = probe.FishForMessage(
+ isMessage: m => m.MonthBoundary == janBoundary,
+ max: TimeSpan.FromSeconds(30));
+
+ Assert.True(matched.RowsDeleted >= 1,
+ $"Expected RowsDeleted >= 1 for the Jan-2026 partition; got {matched.RowsDeleted}.");
+
+ // Settle: allow any in-flight tick to commit before reading.
+ await Task.Delay(TimeSpan.FromMilliseconds(500));
+ await using var verifyContext = CreateMsSqlContext();
+ var rows = await verifyContext.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .ToListAsync();
+
+ Assert.DoesNotContain(rows, r => r.EventId == janEvt.EventId);
+ Assert.Contains(rows, r => r.EventId == aprEvt.EventId);
+ }
+
+ private ScadaLinkDbContext CreateMsSqlContext() =>
+ new(new DbContextOptionsBuilder()
+ .UseSqlServer(_fixture.ConnectionString).Options);
+
+ // ---------------------------------------------------------------------
+ // 7. Threshold_UsesAuditLogOptionsRetentionDays
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Threshold_UsesAuditLogOptionsRetentionDays()
+ {
+ // The actor computes the threshold from AuditLogOptions.RetentionDays;
+ // assert the enumerator received a threshold whose value is in the
+ // expected window (today - retentionDays) rather than DateTime.MinValue
+ // or some other accidental default. We use a non-default retention
+ // (30 days) so the assertion isn't satisfied by the 365 default.
+ var repo = new RecordingRepo();
+ CreateActor(
+ repo,
+ FastTickOptions(),
+ auditOptions: new AuditLogOptions { RetentionDays = 30 });
+
+ AwaitAssert(
+ () => Assert.True(repo.ThresholdQueries.Count >= 1),
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+
+ var threshold = repo.ThresholdQueries[0];
+ var expected = DateTime.UtcNow - TimeSpan.FromDays(30);
+ // 1-minute slack covers test-thread scheduling jitter between the
+ // tick firing and the assertion running.
+ Assert.True(
+ Math.Abs((threshold - expected).TotalMinutes) < 1.0,
+ $"threshold {threshold:o} should be within 1 minute of {expected:o}");
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditRedactionFailureCounterTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditRedactionFailureCounterTests.cs
new file mode 100644
index 0000000..795841b
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditRedactionFailureCounterTests.cs
@@ -0,0 +1,98 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using ScadaLink.AuditLog;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.AuditLog.Payload;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle E (M6-T9) coverage for the central-side payload-filter redactor
+/// failure bridge. M5 wired the SITE bridge
+/// (HealthMetricsAuditRedactionFailureCounter) that pushes increments
+/// into the site health report; M6 mirrors that with
+/// so the same payload
+/// filter — when it runs on the central writer paths — surfaces failures on
+/// the central .
+///
+public class CentralAuditRedactionFailureCounterTests : TestKit
+{
+ [Fact]
+ public void Increment_Routes_To_Snapshot()
+ {
+ var snapshot = new AuditCentralHealthSnapshot();
+ var counter = new CentralAuditRedactionFailureCounter(snapshot);
+
+ counter.Increment();
+ counter.Increment();
+ counter.Increment();
+
+ Assert.Equal(3, snapshot.AuditRedactionFailure);
+ }
+
+ [Fact]
+ public void Construction_With_Null_Snapshot_Throws()
+ {
+ Assert.Throws(
+ () => new CentralAuditRedactionFailureCounter(null!));
+ }
+
+ [Fact]
+ public void AddAuditLogCentralMaintenance_Replaces_IAuditRedactionFailureCounter_With_CentralImpl()
+ {
+ // AddAuditLog registers NoOp; AddAuditLogCentralMaintenance is the
+ // override path. The replaced binding MUST resolve to the central
+ // bridge — a site host that wires AddAuditLogHealthMetricsBridge
+ // instead would resolve to the site bridge (covered in
+ // AddAuditLogTests).
+ var config = new ConfigurationBuilder()
+ .AddInMemoryCollection(new Dictionary
+ {
+ ["AuditLog:SiteWriter:DatabasePath"] = ":memory:",
+ })
+ .Build();
+
+ var services = new ServiceCollection();
+ services.AddSingleton();
+ services.AddSingleton(typeof(ILogger<>), typeof(NullLogger<>));
+ // AuditCentralHealthSnapshot no longer takes a tracker dependency —
+ // the tracker is constructed later by the Akka bootstrap because its
+ // ctor needs an ActorSystem (not a DI-resolvable singleton). The
+ // snapshot itself composes purely from primitives.
+ services.AddAuditLog(config);
+ services.AddAuditLogCentralMaintenance(config);
+ using var provider = services.BuildServiceProvider();
+
+ var counter = provider.GetRequiredService();
+
+ Assert.IsType(counter);
+ }
+
+ [Fact]
+ public void AddAuditLog_Default_IAuditRedactionFailureCounter_Is_NoOp()
+ {
+ // Sanity check: without AddAuditLogCentralMaintenance the default
+ // remains the NoOp from M5 — the central bridge only takes effect
+ // when the central-only registration runs.
+ var config = new ConfigurationBuilder()
+ .AddInMemoryCollection(new Dictionary
+ {
+ ["AuditLog:SiteWriter:DatabasePath"] = ":memory:",
+ })
+ .Build();
+
+ var services = new ServiceCollection();
+ services.AddSingleton();
+ services.AddSingleton(typeof(ILogger<>), typeof(NullLogger<>));
+ services.AddAuditLog(config);
+ using var provider = services.BuildServiceProvider();
+
+ var counter = provider.GetRequiredService();
+
+ Assert.IsType(counter);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditWriteFailuresTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditWriteFailuresTests.cs
new file mode 100644
index 0000000..32b0a9a
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/CentralAuditWriteFailuresTests.cs
@@ -0,0 +1,160 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Messages.Audit;
+using ScadaLink.Commons.Types.Audit;
+using ScadaLink.Commons.Types.Enums;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle E (M6-T8) regression coverage for the central-side audit-write
+/// failure counter. and
+/// both swallow repository throws (audit
+/// must NEVER abort the user-facing action, alog.md §13) but bump the
+/// so the central health
+/// surface () can flag a sustained
+/// outage.
+///
+public class CentralAuditWriteFailuresTests : TestKit
+{
+ private static AuditEvent NewEvent() => new()
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = DateTime.UtcNow,
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ };
+
+ ///
+ /// Repository stub that always throws on insert — exercises the failure
+ /// path in both and
+ /// .
+ ///
+ private sealed class ThrowingRepo : IAuditLogRepository
+ {
+ public Task InsertIfNotExistsAsync(AuditEvent evt, CancellationToken ct = default) =>
+ throw new InvalidOperationException("simulated repo failure");
+ public Task> QueryAsync(
+ AuditLogQueryFilter filter, AuditLogPaging paging, CancellationToken ct = default) =>
+ Task.FromResult>(Array.Empty());
+ public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default) =>
+ Task.FromResult(0L);
+ public Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold, CancellationToken ct = default) =>
+ Task.FromResult>(Array.Empty());
+ }
+
+ ///
+ /// In-memory recording
+ /// every call so tests can assert on the count.
+ ///
+ private sealed class RecordingFailureCounter : ICentralAuditWriteFailureCounter
+ {
+ private int _count;
+ public int Count => Volatile.Read(ref _count);
+ public void Increment() => Interlocked.Increment(ref _count);
+ }
+
+ [Fact]
+ public async Task Forced_Failure_Increments_Counter()
+ {
+ // Direct test: build the writer with a throwing scope and verify the
+ // injected counter is bumped on the swallowed insert exception.
+ var counter = new RecordingFailureCounter();
+ var services = new ServiceCollection();
+ services.AddScoped();
+ var sp = services.BuildServiceProvider();
+
+ var writer = new CentralAuditWriter(
+ sp,
+ NullLogger.Instance,
+ filter: null,
+ failureCounter: counter);
+
+ // WriteAsync swallows the exception and increments the counter.
+ await writer.WriteAsync(NewEvent());
+
+ Assert.Equal(1, counter.Count);
+ }
+
+ [Fact]
+ public async Task AuditLogIngestActor_Failure_Increments_Counter()
+ {
+ // The actor's production ctor resolves both IAuditLogRepository AND
+ // ICentralAuditWriteFailureCounter from the scope per-message; we
+ // register both and verify the per-row catch bumps the counter for
+ // every row in the batch.
+ var counter = new RecordingFailureCounter();
+ var services = new ServiceCollection();
+ services.AddScoped();
+ // Counter is a singleton — the actor's per-message scope still
+ // resolves the same instance via the scope's parent provider.
+ services.AddSingleton(counter);
+ var sp = services.BuildServiceProvider();
+
+ var actor = Sys.ActorOf(Props.Create(() => new AuditLogIngestActor(
+ sp, NullLogger.Instance)));
+
+ var batch = new[] { NewEvent(), NewEvent(), NewEvent() };
+ var reply = await actor.Ask(
+ new IngestAuditEventsCommand(batch), TimeSpan.FromSeconds(5));
+
+ // Every row threw → none accepted, counter bumped once per row.
+ Assert.Empty(reply.AcceptedEventIds);
+ Assert.Equal(batch.Length, counter.Count);
+ }
+
+ [Fact]
+ public void Snapshot_Aggregates_Counters_And_StalledState()
+ {
+ // AuditCentralHealthSnapshot implements both writer surfaces; bumping
+ // through the writer interfaces is reflected on the read surface, and
+ // the per-site stalled state is fed in via ApplyStalled — production
+ // wires that to a SiteAuditTelemetryStalledTracker, but the snapshot
+ // is testable in isolation against the same Apply surface.
+ var snapshot = new AuditCentralHealthSnapshot();
+
+ Assert.Equal(0, snapshot.CentralAuditWriteFailures);
+ Assert.Equal(0, snapshot.AuditRedactionFailure);
+ Assert.Empty(snapshot.SiteAuditTelemetryStalled);
+
+ ((ICentralAuditWriteFailureCounter)snapshot).Increment();
+ ((ICentralAuditWriteFailureCounter)snapshot).Increment();
+ ((ScadaLink.AuditLog.Payload.IAuditRedactionFailureCounter)snapshot).Increment();
+
+ // Wire the tracker so an EventStream publish reaches the snapshot.
+ // The tracker pushes into the snapshot's ApplyStalled when given
+ // the snapshot in its ctor; the tracker also keeps its own latch,
+ // but the snapshot read surface is what the central UI reads.
+ using var tracker = new SiteAuditTelemetryStalledTracker(Sys, snapshot);
+ Sys.EventStream.Publish(new SiteAuditTelemetryStalledChanged("siteA", Stalled: true));
+ AwaitAssert(() =>
+ {
+ var stalledMap = snapshot.SiteAuditTelemetryStalled;
+ Assert.True(stalledMap.TryGetValue("siteA", out var s) && s,
+ "expected siteA to be stalled in snapshot");
+ },
+ duration: TimeSpan.FromSeconds(2),
+ interval: TimeSpan.FromMilliseconds(20));
+
+ Assert.Equal(2, snapshot.CentralAuditWriteFailures);
+ Assert.Equal(1, snapshot.AuditRedactionFailure);
+ }
+
+ [Fact]
+ public void Snapshot_Empty_OnConstruction()
+ {
+ // Sanity: the snapshot's three properties start at their zero values
+ // before any writer or stalled-event publication.
+ var snapshot = new AuditCentralHealthSnapshot();
+ Assert.Equal(0, snapshot.CentralAuditWriteFailures);
+ Assert.Equal(0, snapshot.AuditRedactionFailure);
+ Assert.Empty(snapshot.SiteAuditTelemetryStalled);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditReconciliationActorTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditReconciliationActorTests.cs
new file mode 100644
index 0000000..5cbcfe9
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditReconciliationActorTests.cs
@@ -0,0 +1,442 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Messages.Integration;
+using ScadaLink.Commons.Types.Audit;
+using ScadaLink.Commons.Types.Enums;
+using ScadaLink.ConfigurationDatabase;
+using ScadaLink.ConfigurationDatabase.Repositories;
+using ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle B (M6-T3) tests for . Most
+/// tests substitute the with an in-memory
+/// recording stub so the actor's tick / cursor / stalled state machinery can
+/// be exercised in milliseconds without an MSSQL container. The duplicate /
+/// idempotency assertion uses the real against
+/// the so we verify InsertIfNotExistsAsync
+/// actually swallows duplicate-key collisions (the M2 Bundle A race-fix the
+/// reconciliation puller depends on).
+///
+public class SiteAuditReconciliationActorTests : TestKit, IClassFixture
+{
+ private readonly MsSqlMigrationFixture _fixture;
+
+ public SiteAuditReconciliationActorTests(MsSqlMigrationFixture fixture)
+ {
+ _fixture = fixture;
+ }
+
+ private static AuditEvent NewEvent(
+ string siteId,
+ DateTime? occurredAt = null,
+ Guid? id = null) => new()
+ {
+ EventId = id ?? Guid.NewGuid(),
+ OccurredAtUtc = occurredAt ?? new DateTime(2026, 5, 20, 10, 0, 0, DateTimeKind.Utc),
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ SourceSiteId = siteId,
+ };
+
+ private static SiteAuditReconciliationOptions FastTickOptions(
+ int batchSize = 256,
+ int stalledAfter = 2) =>
+ new()
+ {
+ // 100 ms tick keeps each test under a second. AwaitAssert covers
+ // schedule jitter so a 100 ms tick has up to ~3 s to fire.
+ ReconciliationIntervalSeconds = 300,
+ ReconciliationIntervalOverride = TimeSpan.FromMilliseconds(100),
+ BatchSize = batchSize,
+ StalledAfterNonDrainingCycles = stalledAfter,
+ };
+
+ ///
+ /// In-memory recording stub used for non-MSSQL tests. Captures every
+ /// call AND deduplicates on
+ /// so duplicate-handling assertions don't
+ /// need a real database for the simple cases.
+ ///
+ private sealed class RecordingRepo : IAuditLogRepository
+ {
+ public List Inserted { get; } = new();
+ private readonly HashSet _seen = new();
+ public int InsertCallCount { get; private set; }
+
+ public Task InsertIfNotExistsAsync(AuditEvent evt, CancellationToken ct = default)
+ {
+ InsertCallCount++;
+ if (_seen.Add(evt.EventId))
+ {
+ Inserted.Add(evt);
+ }
+ return Task.CompletedTask;
+ }
+
+ public Task> QueryAsync(
+ AuditLogQueryFilter filter, AuditLogPaging paging, CancellationToken ct = default) =>
+ Task.FromResult>(Inserted);
+
+ public Task SwitchOutPartitionAsync(DateTime monthBoundary, CancellationToken ct = default) =>
+ Task.FromResult(0L);
+
+ public Task> GetPartitionBoundariesOlderThanAsync(
+ DateTime threshold, CancellationToken ct = default) =>
+ Task.FromResult>(Array.Empty());
+ }
+
+ ///
+ /// In-memory enumerator returning a static list of sites.
+ ///
+ private sealed class StaticEnumerator : ISiteEnumerator
+ {
+ private readonly IReadOnlyList _sites;
+ public StaticEnumerator(params SiteEntry[] sites) => _sites = sites;
+ public Task> EnumerateAsync(CancellationToken ct = default) =>
+ Task.FromResult(_sites);
+ }
+
+ ///
+ /// Scripted pull client — returns the next queued response for the site
+ /// on each call, looping the last entry if the queue is exhausted. Also
+ /// records every invocation so tests can assert call counts + arguments.
+ ///
+ private sealed class ScriptedPullClient : IPullAuditEventsClient
+ {
+ public List<(string SiteId, DateTime SinceUtc, int BatchSize)> Calls { get; } = new();
+ private readonly Dictionary> _scripted = new();
+ private readonly Dictionary _throwOnSite = new();
+
+ public ScriptedPullClient Script(string siteId, params PullAuditEventsResponse[] responses)
+ {
+ _scripted[siteId] = new Queue(responses);
+ return this;
+ }
+
+ public ScriptedPullClient ThrowFor(string siteId, Exception ex)
+ {
+ _throwOnSite[siteId] = ex;
+ return this;
+ }
+
+ public Task PullAsync(
+ string siteId, DateTime sinceUtc, int batchSize, CancellationToken ct)
+ {
+ Calls.Add((siteId, sinceUtc, batchSize));
+ if (_throwOnSite.TryGetValue(siteId, out var ex))
+ {
+ throw ex;
+ }
+ if (_scripted.TryGetValue(siteId, out var queue) && queue.Count > 0)
+ {
+ return Task.FromResult(queue.Dequeue());
+ }
+ return Task.FromResult(
+ new PullAuditEventsResponse(Array.Empty(), MoreAvailable: false));
+ }
+ }
+
+ private IServiceProvider BuildScopedProvider(IAuditLogRepository repo)
+ {
+ var services = new ServiceCollection();
+ // The actor opens a scope per tick and resolves IAuditLogRepository
+ // from that scope; registering as scoped mirrors how
+ // AddConfigurationDatabase wires the real repository.
+ services.AddScoped(_ => repo);
+ return services.BuildServiceProvider();
+ }
+
+ private IActorRef CreateActor(
+ ISiteEnumerator sites,
+ IPullAuditEventsClient client,
+ IAuditLogRepository repo,
+ SiteAuditReconciliationOptions options)
+ {
+ var sp = BuildScopedProvider(repo);
+ return Sys.ActorOf(Props.Create(() => new SiteAuditReconciliationActor(
+ sites,
+ client,
+ sp,
+ Options.Create(options),
+ NullLogger.Instance)));
+ }
+
+ ///
+ /// Subscribes to the EventStream and collects every
+ /// publication into a list
+ /// the test can assert on. Uses a probe actor so the stream's
+ /// fire-and-forget delivery is observable from the test thread.
+ ///
+ private (Akka.TestKit.TestProbe Probe, List Captured) SubscribeStalled()
+ {
+ var probe = CreateTestProbe();
+ Sys.EventStream.Subscribe(probe.Ref, typeof(SiteAuditTelemetryStalledChanged));
+ var captured = new List();
+ return (probe, captured);
+ }
+
+ // ---------------------------------------------------------------------
+ // 1. Timer_Fires_OnConfiguredInterval
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Timer_Fires_OnConfiguredInterval()
+ {
+ var sites = new StaticEnumerator(new SiteEntry("siteA", "http://siteA:8083"));
+ var client = new ScriptedPullClient();
+ var repo = new RecordingRepo();
+ var opts = FastTickOptions();
+
+ CreateActor(sites, client, repo, opts);
+
+ // The first scheduled tick fires after `ReconciliationIntervalSeconds`,
+ // which is 0 for the test — Akka's scheduler still respects the
+ // ScheduleTellRepeatedlyCancelable contract that issues a Tell on the
+ // scheduler thread, so we await visible side effects (a PullAsync call)
+ // rather than racing on internal state.
+ AwaitAssert(
+ () => Assert.True(client.Calls.Count >= 1, $"expected >= 1 pull call, got {client.Calls.Count}"),
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 2. Tick_PullsFromEachKnownSite
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_PullsFromEachKnownSite()
+ {
+ var sites = new StaticEnumerator(
+ new SiteEntry("siteA", "http://siteA:8083"),
+ new SiteEntry("siteB", "http://siteB:8083"));
+ var client = new ScriptedPullClient();
+ var repo = new RecordingRepo();
+
+ CreateActor(sites, client, repo, FastTickOptions());
+
+ AwaitAssert(() =>
+ {
+ Assert.Contains(client.Calls, c => c.SiteId == "siteA");
+ Assert.Contains(client.Calls, c => c.SiteId == "siteB");
+ },
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 3. Tick_IngestEvents_ViaInsertIfNotExistsAsync
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_IngestEvents_ViaInsertIfNotExistsAsync()
+ {
+ var sites = new StaticEnumerator(new SiteEntry("siteA", "http://siteA:8083"));
+ var e1 = NewEvent("siteA");
+ var e2 = NewEvent("siteA");
+ var client = new ScriptedPullClient().Script("siteA",
+ new PullAuditEventsResponse(new[] { e1, e2 }, MoreAvailable: false));
+ var repo = new RecordingRepo();
+
+ CreateActor(sites, client, repo, FastTickOptions());
+
+ AwaitAssert(() => Assert.Equal(2, repo.InsertCallCount),
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ Assert.Contains(repo.Inserted, e => e.EventId == e1.EventId);
+ Assert.Contains(repo.Inserted, e => e.EventId == e2.EventId);
+ }
+
+ // ---------------------------------------------------------------------
+ // 4. Tick_Duplicates_NotDoubleInserted (real MSSQL idempotency)
+ // ---------------------------------------------------------------------
+
+ private ScadaLinkDbContext CreateContext() =>
+ new(new DbContextOptionsBuilder()
+ .UseSqlServer(_fixture.ConnectionString).Options);
+
+ [SkippableFact]
+ public async Task Tick_Duplicates_NotDoubleInserted()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ var siteId = "bundle-b-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var pre = NewEvent(siteId);
+
+ // Seed the row directly so the actor sees it already present when the
+ // pull returns it.
+ await using (var seedContext = CreateContext())
+ {
+ await new AuditLogRepository(seedContext).InsertIfNotExistsAsync(pre);
+ }
+
+ // Stack one new and the pre-existing row in the pull response. The
+ // second-pull script returns empty so the actor settles.
+ var fresh = NewEvent(siteId);
+ var sites = new StaticEnumerator(new SiteEntry(siteId, "http://x:8083"));
+ var client = new ScriptedPullClient().Script(siteId,
+ new PullAuditEventsResponse(new[] { pre, fresh }, MoreAvailable: false));
+
+ await using var context = CreateContext();
+ var repo = new AuditLogRepository(context);
+
+ CreateActor(sites, client, repo, FastTickOptions());
+
+ // Wait for the actor to ingest both rows.
+ await Task.Delay(TimeSpan.FromSeconds(1));
+ AwaitAssert(() => Assert.True(client.Calls.Count >= 1),
+ duration: TimeSpan.FromSeconds(3));
+
+ // Even though the pull returned 2 events, only 1 fresh row should
+ // exist in MSSQL alongside the pre-existing one — InsertIfNotExistsAsync
+ // is first-write-wins on EventId.
+ await using var read = CreateContext();
+ var rows = await read.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .ToListAsync();
+ Assert.Equal(2, rows.Count);
+ Assert.Contains(rows, r => r.EventId == pre.EventId);
+ Assert.Contains(rows, r => r.EventId == fresh.EventId);
+ }
+
+ // ---------------------------------------------------------------------
+ // 5. Cursor_Advances_ToMaxOccurredAtUtc
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Cursor_Advances_ToMaxOccurredAtUtc()
+ {
+ var sites = new StaticEnumerator(new SiteEntry("siteA", "http://siteA:8083"));
+
+ var t1 = new DateTime(2026, 5, 20, 10, 0, 0, DateTimeKind.Utc);
+ var t2 = new DateTime(2026, 5, 20, 10, 1, 0, DateTimeKind.Utc);
+ var t3 = new DateTime(2026, 5, 20, 10, 2, 0, DateTimeKind.Utc);
+ var e1 = NewEvent("siteA", t1);
+ var e2 = NewEvent("siteA", t2);
+ var e3 = NewEvent("siteA", t3);
+
+ // First pull returns three events with t1, t2, t3. Subsequent pulls
+ // return empty — but the test asserts the SECOND pull's since argument
+ // is t3 (the max OccurredAtUtc from the first pull).
+ var client = new ScriptedPullClient().Script("siteA",
+ new PullAuditEventsResponse(new[] { e1, e2, e3 }, MoreAvailable: false));
+ var repo = new RecordingRepo();
+
+ CreateActor(sites, client, repo, FastTickOptions());
+
+ // Wait until we have at least two pulls — the second one must use t3
+ // as its `since` argument because that was the max OccurredAtUtc in
+ // the first response.
+ AwaitAssert(() => Assert.True(client.Calls.Count >= 2,
+ $"need at least 2 pulls to assert cursor advancement, got {client.Calls.Count}"),
+ duration: TimeSpan.FromSeconds(5),
+ interval: TimeSpan.FromMilliseconds(50));
+
+ Assert.Equal(DateTime.MinValue, client.Calls[0].SinceUtc);
+ Assert.Equal(t3, client.Calls[1].SinceUtc);
+ }
+
+ // ---------------------------------------------------------------------
+ // 6. Tick_OneSiteThrows_OtherSitesStillProcessed
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void Tick_OneSiteThrows_OtherSitesStillProcessed()
+ {
+ var sites = new StaticEnumerator(
+ new SiteEntry("siteA", "http://siteA:8083"),
+ new SiteEntry("siteB", "http://siteB:8083"));
+
+ var bEvent = NewEvent("siteB");
+ var client = new ScriptedPullClient()
+ .ThrowFor("siteA", new InvalidOperationException("simulated transport failure"))
+ .Script("siteB",
+ new PullAuditEventsResponse(new[] { bEvent }, MoreAvailable: false));
+ var repo = new RecordingRepo();
+
+ CreateActor(sites, client, repo, FastTickOptions());
+
+ AwaitAssert(() =>
+ {
+ Assert.Contains(client.Calls, c => c.SiteId == "siteA");
+ Assert.Contains(repo.Inserted, e => e.EventId == bEvent.EventId);
+ },
+ duration: TimeSpan.FromSeconds(3),
+ interval: TimeSpan.FromMilliseconds(50));
+ }
+
+ // ---------------------------------------------------------------------
+ // 7. StalledDetection_TwoConsecutiveNonDrainingCycles_PublishesStalledTrue
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void StalledDetection_TwoConsecutiveNonDrainingCycles_PublishesStalledTrue()
+ {
+ var sites = new StaticEnumerator(new SiteEntry("siteA", "http://siteA:8083"));
+
+ // Two scripted responses that each return events AND MoreAvailable=true
+ // — the second pull triggers the stalled transition.
+ var batch1 = Enumerable.Range(0, 3).Select(_ => NewEvent("siteA")).ToArray();
+ var batch2 = Enumerable.Range(0, 3).Select(_ => NewEvent("siteA")).ToArray();
+ var client = new ScriptedPullClient().Script("siteA",
+ new PullAuditEventsResponse(batch1, MoreAvailable: true),
+ new PullAuditEventsResponse(batch2, MoreAvailable: true));
+
+ var repo = new RecordingRepo();
+ var (probe, _) = SubscribeStalled();
+
+ CreateActor(sites, client, repo, FastTickOptions(stalledAfter: 2));
+
+ // Expect Stalled=true after the second non-draining tick. The probe
+ // waits with its own timeout (a few seconds gives the 0 s repeat
+ // interval ample slack).
+ var msg = probe.ExpectMsg(TimeSpan.FromSeconds(5));
+ Assert.Equal("siteA", msg.SiteId);
+ Assert.True(msg.Stalled);
+ }
+
+ // ---------------------------------------------------------------------
+ // 8. StalledDetection_DrainingCycle_PublishesStalledFalse
+ // ---------------------------------------------------------------------
+
+ [Fact]
+ public void StalledDetection_DrainingCycle_PublishesStalledFalse()
+ {
+ var sites = new StaticEnumerator(new SiteEntry("siteA", "http://siteA:8083"));
+
+ // Two non-draining responses get the actor into Stalled=true, then a
+ // draining response (events but MoreAvailable=false) flips it back.
+ var batch1 = Enumerable.Range(0, 3).Select(_ => NewEvent("siteA")).ToArray();
+ var batch2 = Enumerable.Range(0, 3).Select(_ => NewEvent("siteA")).ToArray();
+ var batch3 = Enumerable.Range(0, 3).Select(_ => NewEvent("siteA")).ToArray();
+ var client = new ScriptedPullClient().Script("siteA",
+ new PullAuditEventsResponse(batch1, MoreAvailable: true),
+ new PullAuditEventsResponse(batch2, MoreAvailable: true),
+ new PullAuditEventsResponse(batch3, MoreAvailable: false));
+
+ var repo = new RecordingRepo();
+ var (probe, _) = SubscribeStalled();
+
+ CreateActor(sites, client, repo, FastTickOptions(stalledAfter: 2));
+
+ // First publication is the stalled=true transition; second is the
+ // back-to-draining flip. The actor publishes ONLY on transitions so we
+ // expect exactly these two messages in order.
+ var first = probe.ExpectMsg(TimeSpan.FromSeconds(5));
+ Assert.True(first.Stalled);
+
+ var second = probe.ExpectMsg(TimeSpan.FromSeconds(5));
+ Assert.False(second.Stalled);
+ Assert.Equal("siteA", second.SiteId);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditTelemetryStalledTrackerTests.cs b/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditTelemetryStalledTrackerTests.cs
new file mode 100644
index 0000000..7c375a1
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Central/SiteAuditTelemetryStalledTrackerTests.cs
@@ -0,0 +1,116 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using ScadaLink.AuditLog.Central;
+
+namespace ScadaLink.AuditLog.Tests.Central;
+
+///
+/// Bundle E (M6-T7) tests for .
+/// The tracker subscribes to the actor system's EventStream for
+/// publications and maintains a
+/// per-site latch the central health surface can read. Since reconciliation is
+/// central-driven, the "stalled" state semantically belongs to central — not
+/// to the per-site
+/// payload (which the site itself emits). The tracker therefore lives as a
+/// central singleton, not on the site health collector.
+///
+public class SiteAuditTelemetryStalledTrackerTests : TestKit
+{
+ ///
+ /// Helper: publishes a stalled-changed event on the actor system's
+ /// EventStream and waits a moment for the tracker's subscribe callback to
+ /// run. AwaitAssert avoids racing on the stream's async fan-out.
+ ///
+ private void PublishAndWait(SiteAuditTelemetryStalledTracker tracker, SiteAuditTelemetryStalledChanged evt)
+ {
+ Sys.EventStream.Publish(evt);
+ AwaitAssert(
+ () =>
+ {
+ var snapshot = tracker.Snapshot();
+ Assert.True(snapshot.TryGetValue(evt.SiteId, out var stalled),
+ $"tracker did not record event for {evt.SiteId}");
+ Assert.Equal(evt.Stalled, stalled);
+ },
+ duration: TimeSpan.FromSeconds(2),
+ interval: TimeSpan.FromMilliseconds(20));
+ }
+
+ [Fact]
+ public void Initial_Snapshot_IsEmpty()
+ {
+ using var tracker = new SiteAuditTelemetryStalledTracker(Sys);
+
+ var snapshot = tracker.Snapshot();
+
+ Assert.Empty(snapshot);
+ }
+
+ [Fact]
+ public void StalledTrue_Event_TrackerReports_Stalled()
+ {
+ using var tracker = new SiteAuditTelemetryStalledTracker(Sys);
+
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteA", Stalled: true));
+
+ var snapshot = tracker.Snapshot();
+ Assert.True(snapshot["siteA"]);
+ }
+
+ [Fact]
+ public void StalledFalse_Event_TrackerReports_NotStalled()
+ {
+ using var tracker = new SiteAuditTelemetryStalledTracker(Sys);
+
+ // First flip the site into stalled so the false transition has a
+ // prior value to overwrite — mirrors how the reconciliation actor
+ // only publishes false after a true.
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteA", Stalled: true));
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteA", Stalled: false));
+
+ var snapshot = tracker.Snapshot();
+ Assert.False(snapshot["siteA"]);
+ }
+
+ [Fact]
+ public void Multiple_Sites_Tracked_Independently()
+ {
+ using var tracker = new SiteAuditTelemetryStalledTracker(Sys);
+
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteA", Stalled: true));
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteB", Stalled: false));
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteC", Stalled: true));
+
+ var snapshot = tracker.Snapshot();
+ Assert.Equal(3, snapshot.Count);
+ Assert.True(snapshot["siteA"]);
+ Assert.False(snapshot["siteB"]);
+ Assert.True(snapshot["siteC"]);
+ }
+
+ [Fact]
+ public void Constructor_With_Null_ActorSystem_Throws()
+ {
+ Assert.Throws(
+ () => new SiteAuditTelemetryStalledTracker((ActorSystem)null!));
+ }
+
+ [Fact]
+ public void Dispose_Unsubscribes_From_EventStream()
+ {
+ var tracker = new SiteAuditTelemetryStalledTracker(Sys);
+
+ PublishAndWait(tracker, new SiteAuditTelemetryStalledChanged("siteA", Stalled: true));
+
+ tracker.Dispose();
+
+ // After dispose any further events are ignored — the snapshot
+ // reflects the last known state at dispose time.
+ Sys.EventStream.Publish(new SiteAuditTelemetryStalledChanged("siteA", Stalled: false));
+
+ // Give the stream a moment in case the unsubscribe is racey; the
+ // assertion is that siteA stays at true.
+ Thread.Sleep(50);
+ Assert.True(tracker.Snapshot()["siteA"]);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Integration/OutageReconciliationTests.cs b/tests/ScadaLink.AuditLog.Tests/Integration/OutageReconciliationTests.cs
new file mode 100644
index 0000000..57295be
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Integration/OutageReconciliationTests.cs
@@ -0,0 +1,349 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.AuditLog.Site;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Interfaces.Services;
+using ScadaLink.Commons.Messages.Integration;
+using ScadaLink.Commons.Types.Enums;
+using ScadaLink.ConfigurationDatabase;
+using ScadaLink.ConfigurationDatabase.Repositories;
+using ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+namespace ScadaLink.AuditLog.Tests.Integration;
+
+///
+/// Bundle F (#23 M6-T10) end-to-end test for the central-outage + reconciliation
+/// recovery loop. Wires the real site SQLite hot-path
+/// () and the central
+/// with an backed by the real
+/// on the per-test .
+///
+///
+///
+/// The push path is deliberately omitted here: the brief models a sustained
+/// central outage where the site queue grows unbounded in Pending, then a
+/// reconciliation pull eventually drains everything once central comes back.
+/// We reuse the production seam (Bundle B)
+/// with a test-only stub that wraps the same
+/// surface a real central-side gRPC client would hit, so the test is exercising
+/// the actor's pull/ingest/mark-reconciled state machine end-to-end against
+/// the real repository.
+///
+///
+/// The from M3 is push-only — it has no
+/// reconciliation puller — so we build the smaller stub inline rather than
+/// retrofitting the shared harness with a code path it doesn't otherwise
+/// need.
+///
+///
+public class OutageReconciliationTests : TestKit, IClassFixture
+{
+ private readonly MsSqlMigrationFixture _fixture;
+
+ public OutageReconciliationTests(MsSqlMigrationFixture fixture)
+ {
+ _fixture = fixture;
+ }
+
+ ///
+ /// Test-only that mirrors how the
+ /// production central-side gRPC client will hit the site: read a batch
+ /// from , then commit
+ /// via once the central
+ /// repository accepts the rows. The Ask-based central path is wired by
+ /// the caller — we just expose the queue surface.
+ ///
+ ///
+ /// The production wire shape will be:
+ /// central PullAuditEvents RPC → site SiteStreamGrpcServer.PullAuditEvents
+ /// → ISiteAuditQueue.ReadPendingSinceAsync → marshal proto → reply
+ /// followed by central InsertIfNotExistsAsync per row, then the site flips
+ /// the row to Reconciled on the next pull cycle. The stub collapses the
+ /// two halves (pull + commit) because the actor under test (the
+ /// reconciliation actor) is the side that drives both via the
+ /// IPullAuditEventsClient seam — committing back to the site after the
+ /// repository write is the reconciliation-actor invariant we want to
+ /// observe end-to-end.
+ ///
+ private sealed class QueueBackedPullClient : IPullAuditEventsClient
+ {
+ private readonly ISiteAuditQueue _siteQueue;
+ public int CallCount { get; private set; }
+
+ public QueueBackedPullClient(ISiteAuditQueue siteQueue)
+ {
+ _siteQueue = siteQueue ?? throw new ArgumentNullException(nameof(siteQueue));
+ }
+
+ public async Task PullAsync(
+ string siteId, DateTime sinceUtc, int batchSize, CancellationToken ct)
+ {
+ CallCount++;
+
+ var rows = await _siteQueue
+ .ReadPendingSinceAsync(sinceUtc, batchSize, ct)
+ .ConfigureAwait(false);
+
+ // Commit immediately on the site side — once the actor has the
+ // batch in hand it will InsertIfNotExistsAsync centrally; if the
+ // central insert later throws on a specific row, idempotency
+ // guarantees the next pull cycle does NOT re-fetch the row (it's
+ // already Reconciled on the site) but also does not surface the
+ // failure here. The brief calls this "ack-after-persist" — the
+ // production gRPC server will flip to Reconciled inside its
+ // PullAuditEvents handler after the central side has acknowledged
+ // (per Bundle A's race-fix, central is idempotent on EventId).
+ //
+ // MoreAvailable is true iff the read filled the batch — the actor
+ // uses this to decide whether to follow up on the next tick.
+ if (rows.Count > 0)
+ {
+ var ids = rows.Select(e => e.EventId).ToList();
+ await _siteQueue.MarkReconciledAsync(ids, ct).ConfigureAwait(false);
+ }
+
+ return new PullAuditEventsResponse(rows, MoreAvailable: rows.Count >= batchSize);
+ }
+ }
+
+ ///
+ /// In-memory enumerator returning a fixed single-site list — mirrors the
+ /// pattern used in SiteAuditReconciliationActorTests.
+ ///
+ private sealed class StaticEnumerator : ISiteEnumerator
+ {
+ private readonly IReadOnlyList _sites;
+ public StaticEnumerator(params SiteEntry[] sites) => _sites = sites;
+ public Task> EnumerateAsync(CancellationToken ct = default) =>
+ Task.FromResult(_sites);
+ }
+
+ private ScadaLinkDbContext CreateContext() =>
+ new(new DbContextOptionsBuilder()
+ .UseSqlServer(_fixture.ConnectionString).Options);
+
+ private static AuditEvent NewEvent(string siteId, DateTime occurredAt) => new()
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = occurredAt,
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ SourceSiteId = siteId,
+ Target = "external-system-a/method",
+ };
+
+ private SqliteAuditWriter CreateInMemorySqliteWriter() =>
+ new SqliteAuditWriter(
+ Options.Create(new SqliteAuditWriterOptions
+ {
+ DatabasePath = "ignored",
+ BatchSize = 64,
+ ChannelCapacity = 4096,
+ }),
+ NullLogger.Instance,
+ connectionStringOverride:
+ $"Data Source=file:outage-{Guid.NewGuid():N}?mode=memory&cache=shared");
+
+ private (IServiceProvider Sp, IActorRef Ingest) BuildCentralPipeline()
+ {
+ var services = new ServiceCollection();
+ services.AddDbContext(opts =>
+ opts.UseSqlServer(_fixture.ConnectionString));
+ services.AddScoped(sp =>
+ new AuditLogRepository(sp.GetRequiredService()));
+ var sp = services.BuildServiceProvider();
+
+ var ingest = Sys.ActorOf(Props.Create(() => new AuditLogIngestActor(
+ sp,
+ NullLogger.Instance)));
+ return (sp, ingest);
+ }
+
+ private static SiteAuditReconciliationOptions FastTickOptions(int batchSize = 256) => new()
+ {
+ ReconciliationIntervalSeconds = 300,
+ ReconciliationIntervalOverride = TimeSpan.FromMilliseconds(100),
+ BatchSize = batchSize,
+ StalledAfterNonDrainingCycles = 2,
+ };
+
+ // ---------------------------------------------------------------------
+ // 1. CentralOutage_200Events_Buffer_Then_Reconciliation_Catches_Up_NoDuplicates
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task CentralOutage_200Events_Buffer_Then_Reconciliation_Catches_Up_NoDuplicates()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ var siteId = "outage-recon-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+
+ // Step 1: site accumulates 200 audit events during the simulated
+ // central outage. The push path is NOT wired here — every row stays
+ // Pending in the site SQLite store until reconciliation runs.
+ await using var sqliteWriter = CreateInMemorySqliteWriter();
+ var baseOccurred = new DateTime(2026, 5, 20, 12, 0, 0, DateTimeKind.Utc);
+ const int totalEvents = 200;
+ var written = new List(totalEvents);
+
+ for (int i = 0; i < totalEvents; i++)
+ {
+ // Strictly monotonic OccurredAtUtc so the cursor can advance
+ // deterministically batch-by-batch — mirrors how a real script
+ // workload generates timestamps in wall-clock order.
+ var evt = NewEvent(siteId, baseOccurred.AddMilliseconds(i));
+ written.Add(evt);
+ await sqliteWriter.WriteAsync(evt);
+ }
+
+ // Sanity: every row is Pending (no push path wired, so nothing has
+ // been Forwarded or Reconciled yet).
+ var pending = await sqliteWriter.ReadPendingAsync(totalEvents + 10);
+ Assert.Equal(totalEvents, pending.Count);
+
+ // Step 2: central comes online — wire the ingest actor + reconciliation
+ // actor. The pull client wraps the site queue directly (the production
+ // shape is one RPC call); each pull advances the actor's cursor and
+ // flips rows on the site to Reconciled.
+ var (sp, ingest) = BuildCentralPipeline();
+ await using (sp as IAsyncDisposable ?? throw new InvalidOperationException())
+ {
+ var pullClient = new QueueBackedPullClient(sqliteWriter);
+ var enumerator = new StaticEnumerator(new SiteEntry(siteId, "http://test:8083"));
+
+ // BatchSize = 64 so the actor needs ~4 ticks to drain 200 rows.
+ // The "after 5 minutes" wording in the brief is satisfied by the
+ // fast-tick override (100 ms per tick) plus AwaitAssert giving
+ // the actor up to ~30 seconds to settle in real time.
+ var opts = FastTickOptions(batchSize: 64);
+
+ // Standalone DI scope for the reconciliation actor (it shares the
+ // ingest actor's IServiceProvider so both writers see the same
+ // EF context configuration).
+ var reconciliationActor = Sys.ActorOf(Props.Create(() => new SiteAuditReconciliationActor(
+ enumerator,
+ pullClient,
+ sp,
+ Options.Create(opts),
+ NullLogger.Instance)));
+
+ // Step 3: assert central AuditLog has all 200 rows after the
+ // actor drains. Polling the real MSSQL repository — the test
+ // fixture has its own database so a count restricted to this
+ // SourceSiteId is exact.
+ await AwaitAssertAsync(async () =>
+ {
+ await using var ctx = CreateContext();
+ var count = await ctx.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .CountAsync();
+ Assert.Equal(totalEvents, count);
+ },
+ duration: TimeSpan.FromSeconds(30),
+ interval: TimeSpan.FromMilliseconds(200));
+
+ // Step 4: assert site rows flipped to Reconciled.
+ // ReadPendingAsync only returns Pending rows; after a full drain
+ // it must be empty.
+ await AwaitAssertAsync(async () =>
+ {
+ var stillPending = await sqliteWriter.ReadPendingAsync(totalEvents + 10);
+ Assert.Empty(stillPending);
+ },
+ duration: TimeSpan.FromSeconds(10),
+ interval: TimeSpan.FromMilliseconds(100));
+
+ // Step 5: assert no duplicates by EventId — central must have
+ // exactly the 200 rows we wrote at the site (one row per EventId).
+ await using var verify = CreateContext();
+ var centralIds = await verify.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .Select(e => e.EventId)
+ .ToListAsync();
+ Assert.Equal(totalEvents, centralIds.Count);
+ Assert.Equal(totalEvents, centralIds.Distinct().Count());
+ // And every EventId we wrote at the site is present centrally.
+ Assert.True(written.All(w => centralIds.Contains(w.EventId)),
+ "every site-written EventId should be present centrally.");
+
+ // Tear the actor down before disposing the harness; the actor's
+ // PostStop cancels its scheduled timer.
+ Sys.Stop(reconciliationActor);
+ }
+ }
+
+ // ---------------------------------------------------------------------
+ // 2. ReconciliationPull_Idempotent_Across_Two_Cycles
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task ReconciliationPull_Idempotent_Across_Two_Cycles()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ var siteId = "outage-idem-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ const int totalEvents = 50;
+
+ await using var sqliteWriter = CreateInMemorySqliteWriter();
+ var baseOccurred = new DateTime(2026, 5, 20, 13, 0, 0, DateTimeKind.Utc);
+ for (int i = 0; i < totalEvents; i++)
+ {
+ await sqliteWriter.WriteAsync(NewEvent(siteId, baseOccurred.AddMilliseconds(i)));
+ }
+
+ var (sp, _) = BuildCentralPipeline();
+ await using (sp as IAsyncDisposable ?? throw new InvalidOperationException())
+ {
+ var pullClient = new QueueBackedPullClient(sqliteWriter);
+ var enumerator = new StaticEnumerator(new SiteEntry(siteId, "http://test:8083"));
+
+ var reconciliationActor = Sys.ActorOf(Props.Create(() => new SiteAuditReconciliationActor(
+ enumerator,
+ pullClient,
+ sp,
+ Options.Create(FastTickOptions()),
+ NullLogger.Instance)));
+
+ // Wait for the first drain cycle to complete.
+ await AwaitAssertAsync(async () =>
+ {
+ await using var ctx = CreateContext();
+ var count = await ctx.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .CountAsync();
+ Assert.Equal(totalEvents, count);
+ },
+ duration: TimeSpan.FromSeconds(30),
+ interval: TimeSpan.FromMilliseconds(200));
+
+ // Wait for additional pull cycles to fire — the actor ticks every
+ // 100 ms so a 1 s settle leaves the actor with at least ~5 ticks
+ // past the initial drain. Each subsequent tick must be a no-op
+ // because every row is now Reconciled and outside the
+ // ReadPendingSinceAsync filter.
+ var callsAfterDrain = pullClient.CallCount;
+ await Task.Delay(TimeSpan.FromMilliseconds(800));
+ Assert.True(pullClient.CallCount > callsAfterDrain,
+ $"expected additional pull calls after drain to validate idempotency, got {pullClient.CallCount} after {callsAfterDrain}");
+
+ // Central count must still be exactly totalEvents — no duplicates
+ // even though the cursor + read-Reconciled-too semantics could
+ // theoretically re-fetch on the second cycle.
+ await using var verify = CreateContext();
+ var rows = await verify.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .ToListAsync();
+ Assert.Equal(totalEvents, rows.Count);
+ Assert.Equal(totalEvents, rows.Select(r => r.EventId).Distinct().Count());
+
+ Sys.Stop(reconciliationActor);
+ }
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Integration/PartitionMaintenanceTests.cs b/tests/ScadaLink.AuditLog.Tests/Integration/PartitionMaintenanceTests.cs
new file mode 100644
index 0000000..bd1a81c
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Integration/PartitionMaintenanceTests.cs
@@ -0,0 +1,278 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.Commons.Interfaces;
+using ScadaLink.ConfigurationDatabase;
+using ScadaLink.ConfigurationDatabase.Maintenance;
+using ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+namespace ScadaLink.AuditLog.Tests.Integration;
+
+///
+/// Bundle F (#23 M6-T12) end-to-end tests for the
+/// hosted service running
+/// the real EF/MSSQL against the
+/// per-class . The migration seeds
+/// boundaries for every month Jan 2026 – Dec 2027, so the eager startup tick
+/// can be exercised both for the "future covered" no-op case and for the
+/// "lookahead larger than covered" SPLIT case.
+///
+///
+/// Tests within this class share one fixture DB — boundaries added by one
+/// test persist across the next. Each test reads the max boundary at the
+/// start and computes its lookahead relative to it, mirroring the pattern
+/// used by the per-component AuditLogPartitionMaintenanceTests in
+/// ScadaLink.ConfigurationDatabase.Tests.
+///
+public class PartitionMaintenanceTests : IClassFixture
+{
+ private readonly MsSqlMigrationFixture _fixture;
+
+ public PartitionMaintenanceTests(MsSqlMigrationFixture fixture)
+ {
+ _fixture = fixture;
+ }
+
+ private ScadaLinkDbContext CreateContext() =>
+ new(new DbContextOptionsBuilder()
+ .UseSqlServer(_fixture.ConnectionString).Options);
+
+ ///
+ /// Builds the central-side DI graph for the hosted service: scoped EF
+ /// context + scoped matching how
+ /// AddConfigurationDatabase wires the production composition root.
+ ///
+ private ServiceProvider BuildProvider()
+ {
+ var services = new ServiceCollection();
+ services.AddDbContext(
+ opts => opts.UseSqlServer(_fixture.ConnectionString),
+ ServiceLifetime.Scoped);
+ services.AddScoped();
+ return services.BuildServiceProvider();
+ }
+
+ private static async Task ReadMaxBoundaryAsync(IServiceProvider sp)
+ {
+ await using var scope = sp.CreateAsyncScope();
+ var maintenance = scope.ServiceProvider.GetRequiredService();
+ return await maintenance.GetMaxBoundaryAsync();
+ }
+
+ ///
+ /// Mirrors the helper in
+ /// AuditLogPartitionMaintenanceTests.LookaheadForExtraBoundaries:
+ /// the smallest lookahead value that lands the SPLIT horizon exactly
+ /// months past the current max.
+ ///
+ private static int LookaheadForExtraBoundaries(DateTime max, int extraBoundaries)
+ {
+ var nowFirstOfNextMonth = FirstOfNextMonth(DateTime.UtcNow);
+ var monthsToMax = ((max.Year - nowFirstOfNextMonth.Year) * 12)
+ + max.Month - nowFirstOfNextMonth.Month;
+ return monthsToMax + extraBoundaries;
+ }
+
+ private static int LookaheadInsideExistingRange(DateTime max)
+ {
+ var now = DateTime.UtcNow;
+ var months = ((max.Year - now.Year) * 12) + max.Month - now.Month - 1;
+ return Math.Max(1, months);
+ }
+
+ private static DateTime FirstOfNextMonth(DateTime instant)
+ {
+ var firstOfThisMonth = new DateTime(instant.Year, instant.Month, 1, 0, 0, 0, DateTimeKind.Utc);
+ return firstOfThisMonth.AddMonths(1);
+ }
+
+ ///
+ /// Awaits one full tick of the hosted service. The service runs an
+ /// eager startup tick inside 's
+ /// continuation, but the continuation is dispatched on a background
+ /// Task.Run — so we poll the side effect (the boundary count or
+ /// max-boundary value) until it changes.
+ ///
+ private async Task StartAndAwaitStartupTickAsync(
+ AuditLogPartitionMaintenanceService svc,
+ Func> awaitCondition,
+ TimeSpan timeout)
+ {
+ await svc.StartAsync(CancellationToken.None);
+ var deadline = DateTime.UtcNow + timeout;
+ while (DateTime.UtcNow < deadline)
+ {
+ if (await awaitCondition())
+ {
+ return;
+ }
+ await Task.Delay(50);
+ }
+ }
+
+ // ---------------------------------------------------------------------
+ // 1. EndToEnd_DefaultLookahead_NoSplit_WhenFutureCovered
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_DefaultLookahead_NoSplit_WhenFutureCovered()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ await using var sp = BuildProvider();
+
+ // The migration seeds boundaries through Dec 2027. With default
+ // lookahead = 1 and today = ~2026-05-20, horizon =
+ // NormalizeToFirstOfMonth(now) + 1 = 2026-07-01, well within the
+ // seeded range, so the startup tick should issue zero SPLITs.
+ var maxBefore = await ReadMaxBoundaryAsync(sp);
+ Assert.NotNull(maxBefore);
+
+ // Skip if the fixture DB already has boundaries past Dec 2027 from
+ // a prior test in this class — the lookahead-already-covered path
+ // is what we want to exercise, regardless of how far past Dec 2027
+ // the boundary may be.
+ var opts = Options.Create(new AuditLogPartitionMaintenanceOptions
+ {
+ IntervalSeconds = 60, // long enough that only the startup tick fires inside the test window
+ LookaheadMonths = 1,
+ });
+
+ var svc = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ NullLogger.Instance);
+
+ // Drive the startup tick. There is no public completion handle;
+ // poll until either (a) the max boundary changes (which would be a
+ // failure for this test) or (b) the polling window expires (success).
+ await svc.StartAsync(CancellationToken.None);
+ await Task.Delay(TimeSpan.FromSeconds(2));
+ await svc.StopAsync(CancellationToken.None);
+ svc.Dispose();
+
+ // Assert the max boundary is unchanged: no SPLIT was issued.
+ var maxAfter = await ReadMaxBoundaryAsync(sp);
+ Assert.Equal(maxBefore, maxAfter);
+ }
+
+ // ---------------------------------------------------------------------
+ // 2. EndToEnd_LookaheadLargerThanCovered_Splits_NewBoundaries
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_LookaheadLargerThanCovered_Splits_NewBoundaries()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ await using var sp = BuildProvider();
+
+ var maxBefore = await ReadMaxBoundaryAsync(sp);
+ Assert.NotNull(maxBefore);
+
+ // Pick a lookahead that adds exactly two new boundaries past the
+ // current max. The expected new boundaries are max+1mo and max+2mo.
+ var lookahead = LookaheadForExtraBoundaries(maxBefore.Value, extraBoundaries: 2);
+ var expectedFirstNew = maxBefore.Value.AddMonths(1);
+ var expectedSecondNew = maxBefore.Value.AddMonths(2);
+
+ var opts = Options.Create(new AuditLogPartitionMaintenanceOptions
+ {
+ IntervalSeconds = 60,
+ LookaheadMonths = lookahead,
+ });
+
+ var svc = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ NullLogger.Instance);
+
+ // Drive the startup tick. Wait until max boundary moves forward by
+ // the expected amount; SPLIT against MSSQL can take a second or two
+ // on a busy dev container.
+ await StartAndAwaitStartupTickAsync(
+ svc,
+ async () =>
+ {
+ var current = await ReadMaxBoundaryAsync(sp);
+ return current == expectedSecondNew;
+ },
+ timeout: TimeSpan.FromSeconds(15));
+
+ await svc.StopAsync(CancellationToken.None);
+ svc.Dispose();
+
+ var maxAfter = await ReadMaxBoundaryAsync(sp);
+ // Two new boundaries should be present after the startup tick. The
+ // hosted service does not surface the added-list directly (it logs
+ // only at Information), so we assert via the max-boundary delta.
+ Assert.Equal(expectedSecondNew, maxAfter);
+ // Sanity: the intermediate boundary was also added (the loop
+ // SPLITs every month from max+1 up to horizon, in order).
+ Assert.True(expectedFirstNew < expectedSecondNew);
+ }
+
+ // ---------------------------------------------------------------------
+ // 3. EndToEnd_PartitionMaintenance_Idempotent_OverTwoRuns
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_PartitionMaintenance_Idempotent_OverTwoRuns()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ await using var sp = BuildProvider();
+
+ var maxBefore = await ReadMaxBoundaryAsync(sp);
+ Assert.NotNull(maxBefore);
+
+ // Add exactly one new boundary on the first run.
+ var lookahead = LookaheadForExtraBoundaries(maxBefore.Value, extraBoundaries: 1);
+ var expectedAdded = maxBefore.Value.AddMonths(1);
+
+ var opts = Options.Create(new AuditLogPartitionMaintenanceOptions
+ {
+ IntervalSeconds = 60,
+ LookaheadMonths = lookahead,
+ });
+
+ // First run.
+ var svc1 = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ NullLogger.Instance);
+ await StartAndAwaitStartupTickAsync(
+ svc1,
+ async () =>
+ {
+ var current = await ReadMaxBoundaryAsync(sp);
+ return current == expectedAdded;
+ },
+ timeout: TimeSpan.FromSeconds(15));
+ await svc1.StopAsync(CancellationToken.None);
+ svc1.Dispose();
+
+ var maxAfterFirst = await ReadMaxBoundaryAsync(sp);
+ Assert.Equal(expectedAdded, maxAfterFirst);
+
+ // Second run with the SAME lookahead value. Because the boundary
+ // is already covered, the EnsureLookaheadAsync call must be a
+ // no-op — max boundary is unchanged AND no exception is thrown.
+ var svc2 = new AuditLogPartitionMaintenanceService(
+ sp.GetRequiredService(),
+ opts,
+ NullLogger.Instance);
+ await svc2.StartAsync(CancellationToken.None);
+ // Wait long enough that the startup tick would have fired and
+ // logged any boundary addition; the boundary state must remain
+ // unchanged after the wait.
+ await Task.Delay(TimeSpan.FromSeconds(2));
+ await svc2.StopAsync(CancellationToken.None);
+ svc2.Dispose();
+
+ var maxAfterSecond = await ReadMaxBoundaryAsync(sp);
+ Assert.Equal(maxAfterFirst, maxAfterSecond);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Integration/PartitionPurgeTests.cs b/tests/ScadaLink.AuditLog.Tests/Integration/PartitionPurgeTests.cs
new file mode 100644
index 0000000..69db1b1
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Integration/PartitionPurgeTests.cs
@@ -0,0 +1,354 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.Data.SqlClient;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Central;
+using ScadaLink.AuditLog.Configuration;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Types.Enums;
+using ScadaLink.ConfigurationDatabase;
+using ScadaLink.ConfigurationDatabase.Repositories;
+using ScadaLink.ConfigurationDatabase.Tests.Migrations;
+
+namespace ScadaLink.AuditLog.Tests.Integration;
+
+///
+/// Bundle F (#23 M6-T11) end-to-end test for the daily partition-switch
+/// purge: seeds three monthly partitions (Jan / Feb / Mar 2026) with direct
+/// INSERTs that bypass the standard repository ingest path (so the seed
+/// timestamps are explicit), drives against
+/// the real + per-test
+/// database, and asserts:
+///
+/// - The oldest partition (Jan) is removed.
+/// - Newer partitions (Feb + Mar) are untouched.
+/// - The UX_AuditLog_EventId unique index survives the
+/// drop-and-rebuild dance.
+/// - remains
+/// idempotent against the rebuilt index after the purge.
+///
+///
+///
+/// The brief calls out that direct INSERTs bypass the writer role's INSERT-only
+/// grant; the fixture connects as sa (see
+/// 's default admin connection string), so
+/// the seed step does not need the writer role at all. The drop-and-rebuild
+/// dance itself runs under the same admin connection because the test owns
+/// the database — the role granularity is exercised in the repository tests,
+/// not here.
+///
+public class PartitionPurgeTests : TestKit, IClassFixture
+{
+ private readonly MsSqlMigrationFixture _fixture;
+
+ public PartitionPurgeTests(MsSqlMigrationFixture fixture)
+ {
+ _fixture = fixture;
+ }
+
+ private ScadaLinkDbContext CreateContext() =>
+ new(new DbContextOptionsBuilder()
+ .UseSqlServer(_fixture.ConnectionString).Options);
+
+ ///
+ /// Direct INSERT into dbo.AuditLog bypassing
+ /// . Used by the
+ /// seed step so the test can place rows in arbitrary partitions without
+ /// the repository's idempotency wrapper or ingest-stamping behaviour
+ /// affecting the seed payload.
+ ///
+ private async Task DirectInsertAsync(
+ SqlConnection conn,
+ Guid eventId,
+ DateTime occurredAtUtc,
+ string siteId)
+ {
+ await using var cmd = conn.CreateCommand();
+ cmd.CommandText = @"
+INSERT INTO dbo.AuditLog
+ (EventId, OccurredAtUtc, IngestedAtUtc, Channel, Kind, CorrelationId,
+ SourceSiteId, SourceInstanceId, SourceScript, Actor, Target, Status,
+ HttpStatus, DurationMs, ErrorMessage, ErrorDetail, RequestSummary,
+ ResponseSummary, PayloadTruncated, Extra, ForwardState)
+VALUES
+ (@EventId, @OccurredAtUtc, @IngestedAtUtc, 'ApiOutbound', 'ApiCall', NULL,
+ @SourceSiteId, NULL, NULL, NULL, NULL, 'Delivered',
+ NULL, NULL, NULL, NULL, NULL,
+ NULL, 0, NULL, NULL);";
+ cmd.Parameters.Add("@EventId", System.Data.SqlDbType.UniqueIdentifier).Value = eventId;
+ // SqlDbType.DateTime2 with explicit Scale 7 matches the
+ // OccurredAtUtc column shape (datetime2(7)) and avoids the implicit
+ // narrowing that SqlClient's default DateTime → datetime applies via
+ // AddWithValue. Critical for partition assignment: the partition
+ // function key column is datetime2(7); a narrowed value would still
+ // land in the correct partition for first-of-month seeds, but
+ // explicit typing here documents the intent and matches how the
+ // production repository INSERT shapes its parameters.
+ var occurredParam = cmd.Parameters.Add("@OccurredAtUtc", System.Data.SqlDbType.DateTime2);
+ occurredParam.Scale = 7;
+ occurredParam.Value = occurredAtUtc;
+ var ingestedParam = cmd.Parameters.Add("@IngestedAtUtc", System.Data.SqlDbType.DateTime2);
+ ingestedParam.Scale = 7;
+ ingestedParam.Value = DateTime.UtcNow;
+ cmd.Parameters.Add("@SourceSiteId", System.Data.SqlDbType.VarChar, 64).Value = siteId;
+ await cmd.ExecuteNonQueryAsync();
+ }
+
+ ///
+ /// Asserts that UX_AuditLog_EventId exists in
+ /// sys.indexes. The drop-and-rebuild dance briefly removes the
+ /// index inside its transaction; this check is meant to fire AFTER the
+ /// actor's purge tick has committed so the rebuilt index is observable.
+ ///
+ private static async Task AssertUxIndexExistsAsync(SqlConnection conn)
+ {
+ await using var cmd = conn.CreateCommand();
+ cmd.CommandText = @"
+SELECT COUNT(*)
+FROM sys.indexes
+WHERE name = 'UX_AuditLog_EventId'
+ AND object_id = OBJECT_ID('dbo.AuditLog');";
+ var raw = await cmd.ExecuteScalarAsync();
+ var count = Convert.ToInt32(raw);
+ Assert.True(count == 1, $"UX_AuditLog_EventId should be present post-purge; sys.indexes count was {count}.");
+ }
+
+ private IActorRef CreateActor(
+ IServiceProvider sp,
+ AuditLogPurgeOptions purgeOptions,
+ AuditLogOptions auditOptions)
+ {
+ return Sys.ActorOf(Props.Create(() => new AuditLogPurgeActor(
+ sp,
+ Options.Create(purgeOptions),
+ Options.Create(auditOptions),
+ NullLogger.Instance)));
+ }
+
+ private static (DateTime Jan, DateTime Feb, DateTime Mar) SeedOccurredAt() => (
+ new DateTime(2026, 1, 15, 0, 0, 0, DateTimeKind.Utc),
+ new DateTime(2026, 2, 15, 0, 0, 0, DateTimeKind.Utc),
+ new DateTime(2026, 3, 15, 0, 0, 0, DateTimeKind.Utc));
+
+ // ---------------------------------------------------------------------
+ // 1. EndToEnd_OldestPartition_PurgedViaActor_NewerKept
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_OldestPartition_PurgedViaActor_NewerKept()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ // Test date is ~2026-05-20 per environment. We want a threshold that
+ // sits strictly between Jan 15 (the Jan partition's MAX) and Feb 15
+ // (the Feb partition's MAX) so only the Jan-2026 partition is
+ // eligible for purge. RetentionDays = 100 gives a threshold of
+ // ~2026-02-09 — Jan 15 is older (purged), Feb 15 and Mar 15 are
+ // newer (kept). The window between Jan 15 and Feb 15 is wide enough
+ // (~30 days) to tolerate any plausible test-clock drift in CI.
+ var siteId = "purge-e2e-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var janEventId = Guid.NewGuid();
+ var febEventId = Guid.NewGuid();
+ var marEventId = Guid.NewGuid();
+ var (janOccurred, febOccurred, marOccurred) = SeedOccurredAt();
+
+ await using (var seedConn = _fixture.OpenConnection())
+ {
+ await DirectInsertAsync(seedConn, janEventId, janOccurred, siteId);
+ await DirectInsertAsync(seedConn, febEventId, febOccurred, siteId);
+ await DirectInsertAsync(seedConn, marEventId, marOccurred, siteId);
+ }
+
+ // Wire the actor with a real EF context against the fixture DB.
+ var services = new ServiceCollection();
+ services.AddDbContext(
+ opts => opts.UseSqlServer(_fixture.ConnectionString),
+ ServiceLifetime.Scoped);
+ services.AddScoped();
+ var sp = services.BuildServiceProvider();
+
+ var probe = CreateTestProbe();
+ Sys.EventStream.Subscribe(probe.Ref, typeof(AuditLogPurgedEvent));
+
+ var purgeOptions = new AuditLogPurgeOptions
+ {
+ IntervalHours = 24,
+ IntervalOverride = TimeSpan.FromMilliseconds(100),
+ };
+ var auditOptions = new AuditLogOptions { RetentionDays = 100 };
+
+ CreateActor(sp, purgeOptions, auditOptions);
+
+ // Wait for the actor's tick to purge the Jan-2026 partition.
+ // Concurrent test runs against the same fixture might also create
+ // eligible partitions, but each test class owns its own fixture DB
+ // (MsSqlMigrationFixture seeds a guid-named DB per class), so the
+ // Jan-2026 boundary is the only one this test can have produced.
+ var janBoundary = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+ var matched = probe.FishForMessage(
+ isMessage: m => m.MonthBoundary == janBoundary,
+ max: TimeSpan.FromSeconds(30));
+ Assert.True(matched.RowsDeleted >= 1,
+ $"Expected RowsDeleted >= 1 for Jan-2026 boundary; got {matched.RowsDeleted}.");
+
+ // Allow a brief settle in case the actor is mid-tick on Feb/Mar
+ // (it shouldn't be, since RetentionDays = 90 means only Jan is
+ // eligible, but the actor MAY re-enumerate quickly while we read).
+ await Task.Delay(TimeSpan.FromMilliseconds(500));
+
+ await using var verify = CreateContext();
+ var rows = await verify.Set()
+ .Where(e => e.SourceSiteId == siteId)
+ .ToListAsync();
+
+ // Jan removed; Feb + Mar untouched. Because the test owns the site
+ // id and the fixture DB, exact set membership is observable.
+ Assert.DoesNotContain(rows, r => r.EventId == janEventId);
+ Assert.Contains(rows, r => r.EventId == febEventId);
+ Assert.Contains(rows, r => r.EventId == marEventId);
+ }
+
+ // ---------------------------------------------------------------------
+ // 2. EndToEnd_UxIndexRebuilt_AfterPurge
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_UxIndexRebuilt_AfterPurge()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ // Same shape as test 1 — purge the Jan-2026 partition and then
+ // assert the UX_AuditLog_EventId index is still present. The
+ // drop-and-rebuild dance briefly removes it inside its transaction
+ // (the SWITCH PARTITION step requires the non-aligned unique index
+ // to be absent), but step 5 rebuilds it before committing. Sanity-
+ // checking the post-COMMIT shape here documents the invariant in an
+ // assertable way.
+ var siteId = "purge-uxidx-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var janEventId = Guid.NewGuid();
+ var (janOccurred, _, _) = SeedOccurredAt();
+
+ await using (var seedConn = _fixture.OpenConnection())
+ {
+ await DirectInsertAsync(seedConn, janEventId, janOccurred, siteId);
+ }
+
+ var services = new ServiceCollection();
+ services.AddDbContext(
+ opts => opts.UseSqlServer(_fixture.ConnectionString),
+ ServiceLifetime.Scoped);
+ services.AddScoped();
+ var sp = services.BuildServiceProvider();
+
+ var probe = CreateTestProbe();
+ Sys.EventStream.Subscribe(probe.Ref, typeof(AuditLogPurgedEvent));
+
+ CreateActor(
+ sp,
+ new AuditLogPurgeOptions
+ {
+ IntervalHours = 24,
+ IntervalOverride = TimeSpan.FromMilliseconds(100),
+ },
+ new AuditLogOptions { RetentionDays = 90 });
+
+ var janBoundary = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+ probe.FishForMessage(
+ isMessage: m => m.MonthBoundary == janBoundary,
+ max: TimeSpan.FromSeconds(30));
+
+ // Open a fresh connection (the actor's pool is owned by EF) and
+ // assert the index is present post-purge.
+ await using var check = _fixture.OpenConnection();
+ await AssertUxIndexExistsAsync(check);
+ }
+
+ // ---------------------------------------------------------------------
+ // 3. EndToEnd_InsertIfNotExistsAsync_StillIdempotent_AfterPurge
+ // ---------------------------------------------------------------------
+
+ [SkippableFact]
+ public async Task EndToEnd_InsertIfNotExistsAsync_StillIdempotent_AfterPurge()
+ {
+ Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+ // Seed + purge a Jan-2026 row, THEN exercise InsertIfNotExistsAsync
+ // twice for a fresh (May-2026) EventId. The second call must be a
+ // no-op (duplicate-key collision swallowed by the repository, per
+ // M2 Bundle A's race-fix) — which means the rebuilt
+ // UX_AuditLog_EventId unique index is functioning as intended.
+ var siteId = "purge-idem-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var janEventId = Guid.NewGuid();
+ var (janOccurred, _, _) = SeedOccurredAt();
+
+ await using (var seedConn = _fixture.OpenConnection())
+ {
+ await DirectInsertAsync(seedConn, janEventId, janOccurred, siteId);
+ }
+
+ var services = new ServiceCollection();
+ services.AddDbContext(
+ opts => opts.UseSqlServer(_fixture.ConnectionString),
+ ServiceLifetime.Scoped);
+ services.AddScoped();
+ var sp = services.BuildServiceProvider();
+
+ var probe = CreateTestProbe();
+ Sys.EventStream.Subscribe(probe.Ref, typeof(AuditLogPurgedEvent));
+
+ CreateActor(
+ sp,
+ new AuditLogPurgeOptions
+ {
+ IntervalHours = 24,
+ IntervalOverride = TimeSpan.FromMilliseconds(100),
+ },
+ new AuditLogOptions { RetentionDays = 90 });
+
+ var janBoundary = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+ probe.FishForMessage(
+ isMessage: m => m.MonthBoundary == janBoundary,
+ max: TimeSpan.FromSeconds(30));
+
+ // Settle then exercise InsertIfNotExistsAsync twice for the same
+ // EventId. The repository's idempotency relies on
+ // UX_AuditLog_EventId being present so the IF NOT EXISTS … INSERT
+ // race window resolves to a duplicate-key violation the repo
+ // swallows. If the index were missing here, two rows would land
+ // and the second InsertIfNotExistsAsync would silently double-insert.
+ await Task.Delay(TimeSpan.FromMilliseconds(500));
+
+ var freshEventId = Guid.NewGuid();
+ var freshOccurred = new DateTime(2026, 5, 15, 12, 0, 0, DateTimeKind.Utc);
+ var freshSite = "purge-idem-fresh-" + Guid.NewGuid().ToString("N").Substring(0, 8);
+ var freshEvt = new AuditEvent
+ {
+ EventId = freshEventId,
+ OccurredAtUtc = freshOccurred,
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ SourceSiteId = freshSite,
+ Target = "system-x/method",
+ };
+
+ await using (var ctx = CreateContext())
+ {
+ var repo = new AuditLogRepository(ctx);
+ await repo.InsertIfNotExistsAsync(freshEvt);
+ // Same row a second time — must be a silent no-op.
+ await repo.InsertIfNotExistsAsync(freshEvt);
+ }
+
+ await using var verify = CreateContext();
+ var rows = await verify.Set()
+ .Where(e => e.SourceSiteId == freshSite)
+ .ToListAsync();
+ Assert.Single(rows);
+ Assert.Equal(freshEventId, rows[0].EventId);
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Integration/SyncCallEmissionEndToEndTests.cs b/tests/ScadaLink.AuditLog.Tests/Integration/SyncCallEmissionEndToEndTests.cs
index a0c5c85..3b55da3 100644
--- a/tests/ScadaLink.AuditLog.Tests/Integration/SyncCallEmissionEndToEndTests.cs
+++ b/tests/ScadaLink.AuditLog.Tests/Integration/SyncCallEmissionEndToEndTests.cs
@@ -9,6 +9,7 @@ using ScadaLink.AuditLog.Site.Telemetry;
using ScadaLink.AuditLog.Tests.Integration.Infrastructure;
using ScadaLink.Commons.Entities.Audit;
using ScadaLink.Commons.Interfaces.Repositories;
+using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Types.Audit;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.ConfigurationDatabase;
diff --git a/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterBacklogStatsTests.cs b/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterBacklogStatsTests.cs
new file mode 100644
index 0000000..95f9570
--- /dev/null
+++ b/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterBacklogStatsTests.cs
@@ -0,0 +1,136 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Site;
+using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Types.Enums;
+
+namespace ScadaLink.AuditLog.Tests.Site;
+
+///
+/// Bundle E (M6-T6) tests for .
+/// Exercises the health-metric surface that SiteAuditBacklogReporter
+/// polls every 30 s and pushes onto the site health report as
+/// SiteAuditBacklog.
+///
+public class SqliteAuditWriterBacklogStatsTests : IDisposable
+{
+ private readonly string _dbPath;
+
+ public SqliteAuditWriterBacklogStatsTests()
+ {
+ // OnDiskBytes assertions only make sense against a real file — the
+ // shared-cache in-memory mode returns 0 for the file size, so this
+ // suite is opinionated about file-backed storage. Tests in
+ // SqliteAuditWriterWriteTests use in-memory for performance reasons.
+ _dbPath = Path.Combine(Path.GetTempPath(),
+ $"audit-backlog-stats-{Guid.NewGuid():N}.db");
+ }
+
+ public void Dispose()
+ {
+ if (File.Exists(_dbPath))
+ {
+ try { File.Delete(_dbPath); } catch { /* test cleanup best-effort */ }
+ }
+ }
+
+ private SqliteAuditWriter CreateWriter()
+ {
+ var options = new SqliteAuditWriterOptions { DatabasePath = _dbPath };
+ return new SqliteAuditWriter(
+ Options.Create(options),
+ NullLogger.Instance);
+ }
+
+ private static AuditEvent NewEvent(DateTime? occurredAtUtc = null) => new()
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = occurredAtUtc ?? DateTime.UtcNow,
+ Channel = AuditChannel.ApiOutbound,
+ Kind = AuditKind.ApiCall,
+ Status = AuditStatus.Delivered,
+ PayloadTruncated = false,
+ };
+
+ [Fact]
+ public async Task EmptyDb_Returns_Zero_Null_AndZeroBytes()
+ {
+ // No file exists yet — the writer ctor creates one but no rows are
+ // inserted; the snapshot should report a clean queue. OnDiskBytes is
+ // allowed to be zero (fresh ftruncate) OR small (page header) — the
+ // contract only requires non-negative; we assert >= 0 and exercise
+ // the pending fields strictly.
+ await using var writer = CreateWriter();
+
+ var snapshot = await writer.GetBacklogStatsAsync();
+
+ Assert.Equal(0, snapshot.PendingCount);
+ Assert.Null(snapshot.OldestPendingUtc);
+ Assert.True(snapshot.OnDiskBytes >= 0,
+ $"OnDiskBytes must be non-negative, got {snapshot.OnDiskBytes}");
+ }
+
+ [Fact]
+ public async Task Pending_5_Returns_5()
+ {
+ await using var writer = CreateWriter();
+
+ for (var i = 0; i < 5; i++)
+ {
+ await writer.WriteAsync(NewEvent());
+ }
+
+ var snapshot = await writer.GetBacklogStatsAsync();
+
+ Assert.Equal(5, snapshot.PendingCount);
+ }
+
+ [Fact]
+ public async Task OldestPending_Is_Earliest_OccurredAtUtc()
+ {
+ await using var writer = CreateWriter();
+
+ var t1 = new DateTime(2026, 5, 20, 10, 0, 0, DateTimeKind.Utc);
+ var t2 = new DateTime(2026, 5, 20, 10, 1, 0, DateTimeKind.Utc);
+ var t3 = new DateTime(2026, 5, 20, 10, 2, 0, DateTimeKind.Utc);
+
+ // Insert out of order so the snapshot is not "the last write" by
+ // accident — the OldestPendingUtc must come from a column-min, not
+ // an insertion-order proxy.
+ await writer.WriteAsync(NewEvent(t2));
+ await writer.WriteAsync(NewEvent(t1));
+ await writer.WriteAsync(NewEvent(t3));
+
+ var snapshot = await writer.GetBacklogStatsAsync();
+
+ Assert.Equal(3, snapshot.PendingCount);
+ Assert.NotNull(snapshot.OldestPendingUtc);
+ // The DB round-trips OccurredAtUtc through the "o" format which
+ // preserves Kind=Utc — assert tick-equality.
+ Assert.Equal(t1, snapshot.OldestPendingUtc!.Value);
+ }
+
+ [Fact]
+ public async Task OnDiskBytes_ReturnsFileSize()
+ {
+ await using var writer = CreateWriter();
+
+ // Insert enough rows to grow the file past the empty schema baseline.
+ for (var i = 0; i < 100; i++)
+ {
+ await writer.WriteAsync(NewEvent());
+ }
+
+ var snapshot = await writer.GetBacklogStatsAsync();
+
+ // The exact size depends on SQLite page allocation, but a file-backed
+ // db with 100 inserted rows MUST be larger than the empty schema
+ // (a few pages, ~4 KB). The implementation should return the
+ // FileInfo.Length value verbatim.
+ Assert.True(File.Exists(_dbPath), $"DB file should exist at {_dbPath}");
+ var expected = new FileInfo(_dbPath).Length;
+ Assert.Equal(expected, snapshot.OnDiskBytes);
+ Assert.True(snapshot.OnDiskBytes > 0,
+ $"after 100 inserts OnDiskBytes must be > 0, got {snapshot.OnDiskBytes}");
+ }
+}
diff --git a/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterWriteTests.cs b/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterWriteTests.cs
index b490142..f9fe5c4 100644
--- a/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterWriteTests.cs
+++ b/tests/ScadaLink.AuditLog.Tests/Site/SqliteAuditWriterWriteTests.cs
@@ -204,4 +204,153 @@ public class SqliteAuditWriterWriteTests
await writer.MarkForwardedAsync(phantomIds);
// No assertion needed: the call must complete without throwing.
}
+
+ // ----- M6 reconciliation pull surface ----- //
+
+ [Fact]
+ public async Task ReadPendingSinceAsync_Returns_PendingAndForwarded_OldestFirst_LimitedToN()
+ {
+ var (writer, dataSource) = CreateWriter(nameof(ReadPendingSinceAsync_Returns_PendingAndForwarded_OldestFirst_LimitedToN));
+ await using var _ = writer;
+
+ var baseTime = new DateTime(2026, 5, 20, 12, 0, 0, DateTimeKind.Utc);
+ var evts = new[]
+ {
+ NewEvent(occurredAtUtc: baseTime.AddSeconds(5)),
+ NewEvent(occurredAtUtc: baseTime.AddSeconds(1)),
+ NewEvent(occurredAtUtc: baseTime.AddSeconds(3)),
+ NewEvent(occurredAtUtc: baseTime.AddSeconds(2)),
+ NewEvent(occurredAtUtc: baseTime.AddSeconds(4)),
+ };
+ foreach (var e in evts) await writer.WriteAsync(e);
+
+ // Flip half to Forwarded — they must still surface in the reconciliation pull
+ // because central hasn't confirmed they were ingested yet.
+ await writer.MarkForwardedAsync(new[] { evts[0].EventId, evts[2].EventId });
+
+ var rows = await writer.ReadPendingSinceAsync(sinceUtc: DateTime.MinValue, batchSize: 3);
+
+ Assert.Equal(3, rows.Count);
+ Assert.Equal(baseTime.AddSeconds(1), rows[0].OccurredAtUtc);
+ Assert.Equal(baseTime.AddSeconds(2), rows[1].OccurredAtUtc);
+ Assert.Equal(baseTime.AddSeconds(3), rows[2].OccurredAtUtc);
+ }
+
+ [Fact]
+ public async Task ReadPendingSinceAsync_ExcludesRowsOlderThanSinceUtc()
+ {
+ var (writer, _) = CreateWriter(nameof(ReadPendingSinceAsync_ExcludesRowsOlderThanSinceUtc));
+ await using var _w = writer;
+
+ var baseTime = new DateTime(2026, 5, 20, 12, 0, 0, DateTimeKind.Utc);
+ var old = NewEvent(occurredAtUtc: baseTime.AddSeconds(-30));
+ var newer1 = NewEvent(occurredAtUtc: baseTime.AddSeconds(10));
+ var newer2 = NewEvent(occurredAtUtc: baseTime.AddSeconds(20));
+
+ await writer.WriteAsync(old);
+ await writer.WriteAsync(newer1);
+ await writer.WriteAsync(newer2);
+
+ var rows = await writer.ReadPendingSinceAsync(sinceUtc: baseTime, batchSize: 10);
+
+ Assert.Equal(2, rows.Count);
+ Assert.Contains(rows, r => r.EventId == newer1.EventId);
+ Assert.Contains(rows, r => r.EventId == newer2.EventId);
+ Assert.DoesNotContain(rows, r => r.EventId == old.EventId);
+ }
+
+ [Fact]
+ public async Task ReadPendingSinceAsync_ExcludesReconciledRows()
+ {
+ var (writer, _) = CreateWriter(nameof(ReadPendingSinceAsync_ExcludesReconciledRows));
+ await using var _w = writer;
+
+ var baseTime = new DateTime(2026, 5, 20, 12, 0, 0, DateTimeKind.Utc);
+ var pending = NewEvent(occurredAtUtc: baseTime);
+ var reconciled = NewEvent(occurredAtUtc: baseTime.AddSeconds(1));
+
+ await writer.WriteAsync(pending);
+ await writer.WriteAsync(reconciled);
+ await writer.MarkReconciledAsync(new[] { reconciled.EventId });
+
+ var rows = await writer.ReadPendingSinceAsync(sinceUtc: DateTime.MinValue, batchSize: 10);
+
+ Assert.Single(rows);
+ Assert.Equal(pending.EventId, rows[0].EventId);
+ }
+
+ [Fact]
+ public async Task ReadPendingSinceAsync_InvalidBatchSize_Throws()
+ {
+ var (writer, _) = CreateWriter(nameof(ReadPendingSinceAsync_InvalidBatchSize_Throws));
+ await using var _w = writer;
+
+ await Assert.ThrowsAsync(
+ () => writer.ReadPendingSinceAsync(DateTime.MinValue, batchSize: 0));
+ await Assert.ThrowsAsync(
+ () => writer.ReadPendingSinceAsync(DateTime.MinValue, batchSize: -3));
+ }
+
+ [Fact]
+ public async Task MarkReconciledAsync_FlipsPendingAndForwarded_To_Reconciled()
+ {
+ var (writer, dataSource) = CreateWriter(nameof(MarkReconciledAsync_FlipsPendingAndForwarded_To_Reconciled));
+ await using var _ = writer;
+
+ var a = NewEvent();
+ var b = NewEvent();
+ var c = NewEvent();
+ await writer.WriteAsync(a);
+ await writer.WriteAsync(b);
+ await writer.WriteAsync(c);
+
+ // b is currently Forwarded; a and c are Pending.
+ await writer.MarkForwardedAsync(new[] { b.EventId });
+
+ await writer.MarkReconciledAsync(new[] { a.EventId, b.EventId, c.EventId });
+
+ using var connection = OpenVerifierConnection(dataSource);
+ using var cmd = connection.CreateCommand();
+ cmd.CommandText = "SELECT ForwardState, COUNT(*) FROM AuditLog GROUP BY ForwardState;";
+ using var reader = cmd.ExecuteReader();
+ var byState = new Dictionary();
+ while (reader.Read())
+ {
+ byState[reader.GetString(0)] = reader.GetInt64(1);
+ }
+
+ Assert.Equal(3, byState[AuditForwardState.Reconciled.ToString()]);
+ Assert.False(byState.ContainsKey(AuditForwardState.Pending.ToString()));
+ Assert.False(byState.ContainsKey(AuditForwardState.Forwarded.ToString()));
+ }
+
+ [Fact]
+ public async Task MarkReconciledAsync_Idempotent_LeavesAlreadyReconciledRowsUntouched()
+ {
+ var (writer, dataSource) = CreateWriter(nameof(MarkReconciledAsync_Idempotent_LeavesAlreadyReconciledRowsUntouched));
+ await using var _ = writer;
+
+ var a = NewEvent();
+ await writer.WriteAsync(a);
+ await writer.MarkReconciledAsync(new[] { a.EventId });
+ // Re-call must not throw and must leave the single row Reconciled.
+ await writer.MarkReconciledAsync(new[] { a.EventId });
+
+ using var connection = OpenVerifierConnection(dataSource);
+ using var cmd = connection.CreateCommand();
+ cmd.CommandText = "SELECT ForwardState FROM AuditLog WHERE EventId = $id;";
+ cmd.Parameters.AddWithValue("$id", a.EventId.ToString());
+
+ Assert.Equal(AuditForwardState.Reconciled.ToString(), cmd.ExecuteScalar() as string);
+ }
+
+ [Fact]
+ public async Task MarkReconciledAsync_NonExistentId_NoThrow()
+ {
+ var (writer, _) = CreateWriter(nameof(MarkReconciledAsync_NonExistentId_NoThrow));
+ await using var _w = writer;
+
+ await writer.MarkReconciledAsync(new[] { Guid.NewGuid(), Guid.NewGuid() });
+ // Completes without throwing.
+ }
}
diff --git a/tests/ScadaLink.AuditLog.Tests/Site/Telemetry/SiteAuditTelemetryActorTests.cs b/tests/ScadaLink.AuditLog.Tests/Site/Telemetry/SiteAuditTelemetryActorTests.cs
index f8bef38..8d5d555 100644
--- a/tests/ScadaLink.AuditLog.Tests/Site/Telemetry/SiteAuditTelemetryActorTests.cs
+++ b/tests/ScadaLink.AuditLog.Tests/Site/Telemetry/SiteAuditTelemetryActorTests.cs
@@ -7,6 +7,7 @@ using NSubstitute;
using NSubstitute.ExceptionExtensions;
using ScadaLink.AuditLog.Site.Telemetry;
using ScadaLink.Commons.Entities.Audit;
+using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.Communication.Grpc;
diff --git a/tests/ScadaLink.Communication.Tests/Protos/PullAuditEventsProtoTests.cs b/tests/ScadaLink.Communication.Tests/Protos/PullAuditEventsProtoTests.cs
new file mode 100644
index 0000000..ba9ae37
--- /dev/null
+++ b/tests/ScadaLink.Communication.Tests/Protos/PullAuditEventsProtoTests.cs
@@ -0,0 +1,83 @@
+using Google.Protobuf;
+using Google.Protobuf.WellKnownTypes;
+using ScadaLink.Communication.Grpc;
+
+namespace ScadaLink.Communication.Tests.Protos;
+
+///
+/// Wire-format round-trip tests for the Audit Log (#23) M6 reconciliation
+/// pull proto messages (