Adds three KPI tiles to the central Health dashboard for the Audit channel:
volume (rows in the last hour), error rate (Failed/Parked/Discarded over
total), and backlog (sum of SiteAuditBacklog.PendingCount across all sites).
Repo + service:
- IAuditLogRepository.GetKpiSnapshotAsync(window, nowUtc) — single aggregate
SELECT over the trailing window returning total + error counts; nowUtc is
optional for production callers and pinned by integration tests against the
shared MSSQL fixture so the global counts are deterministic.
- AuditLogQueryService.GetKpiSnapshotAsync() — composes the repo aggregate
with a sum of SiteAuditBacklog.PendingCount read from ICentralHealthAggregator.
- AuditLogKpiSnapshot record in Commons/Types/.
UI:
- New AuditKpiTiles Blazor component (Components/Health/) — three Bootstrap
card-tiles, click navigates to /audit/log with the matching pre-filter.
- Health.razor wires the tiles in alongside the existing Notification Outbox
KPIs; LoadAuditKpis() runs on every 10s refresh tick and degrades to em
dashes + inline error if the query fails.
- AuditLogPage extended to parse ?status= so the error-rate tile drill-in
(?status=Failed) auto-loads the grid.
Tests:
- AuditLogRepositoryTests: GetKpiSnapshotAsync mixed-status + empty-window
cases against the MSSQL migration fixture.
- AuditLogQueryServiceTests: forwarding + backlog composition; sites with
null SiteAuditBacklog contribute zero.
- AuditKpiTilesTests: 9 bUnit tests covering tile render, error-rate maths
with safe zero-events handling, em-dash unavailable path, click-through
navigation, and warning/danger border thresholds.
- HealthPageTests: new Renders_AuditKpiTiles_WithValues plus IAuditLogQueryService
stub registration in the constructor so existing outbox tests still pass.
- AuditLogPageScaffoldTests: ?status=Failed auto-load + unknown status drop.
The snapshot's per-site stalled latch now lives on the snapshot itself
and is fed by SiteAuditTelemetryStalledTracker via ApplyStalled, removing
the chain that required ActorSystem at DI composition time. The tracker
is now constructed by AkkaHostedService once ActorSystem.Create returns,
with a lock-guarded auxiliary-disposable list so concurrent host
start/stop in tests cannot race the enumeration.
Central singleton (M6-T4 Bundle C) that drives the daily AuditLog partition
purge. On a configurable timer (default 24 hours) the actor:
1. Queries IAuditLogRepository.GetPartitionBoundariesOlderThanAsync for
monthly boundaries whose latest OccurredAtUtc is older than
DateTime.UtcNow - AuditLogOptions.RetentionDays.
2. For each eligible boundary calls SwitchOutPartitionAsync, which runs
the drop-and-rebuild dance around UX_AuditLog_EventId.
3. Publishes AuditLogPurgedEvent(boundary, rowsDeleted, durationMs) on
the actor-system EventStream so the Bundle E central health collector
and ops surfaces can subscribe without coupling to this actor.
Co-changes:
* SwitchOutPartitionAsync returns long (rows deleted) — sampled BEFORE the
switch via COUNT_BIG over the per-partition filter so the count
reflects what the switch removed, not a post-purge scan of a table that
no longer exists. All stub implementations updated.
* AuditLogPurgeOptions: IntervalHours (default 24), IntervalOverride for
tests, Interval property resolving either.
* AuditLogPurgedEvent: record with MonthBoundary, RowsDeleted, DurationMs.
Behavior:
* Continue-on-error per boundary — one partition that throws does NOT
abandon the rest of the tick.
* DI scope opened per tick (IAuditLogRepository is a SCOPED EF Core
service); mirrors SiteAuditReconciliationActor and AuditLogIngestActor.
* SupervisorStrategy Resume keeps the singleton alive across leaked
exceptions.
* EventStream capture BEFORE the first await — Context is unsafe after
await in async receive handlers (same pattern as Sender-capture in
AuditLogIngestActor.OnIngestAsync).
Tests:
* Tick_Fires_OnDailyInterval — visible timer side effect.
* Tick_OldPartitions_SwitchedOut — both seeded boundaries purged.
* Tick_NewerPartitions_Untouched — empty enumerator → no switches.
* Tick_PublishesPurgedEvent_WithRowCount — AuditLogPurgedEvent carries
RowsDeleted and DurationMs.
* Tick_SwitchThrows_OtherPartitionsStillProcessed — continue-on-error.
* Threshold_UsesAuditLogOptionsRetentionDays — non-default 30-day window
computed from UtcNow - RetentionDays.
* EndToEnd_RealPartition_RowsRemoved_PurgedEventPublished — TestKit +
MsSqlMigrationFixture: real partitioned table, Jan-2026 row purged,
Apr-2026 row kept, AuditLogPurgedEvent observed via probe.
Replaces M1's NotSupportedException stub with the production drop-DROP-INDEX
→ CREATE-staging → SWITCH PARTITION → DROP-staging → CREATE-INDEX dance
documented in alog.md §4. UX_AuditLog_EventId is intentionally non-aligned
with ps_AuditLog_Month so single-column EventId uniqueness can be enforced
cheaply for InsertIfNotExistsAsync; SQL Server rejects ALTER TABLE SWITCH
while a non-aligned unique index is present, so the implementation drops
it, switches the partition data into a GUID-suffixed staging table on
[PRIMARY], drops staging (discarding the rows), and rebuilds the unique
index — all inside an explicit transaction with a CATCH that guarantees
the unique index is rebuilt regardless of failure point.
Also adds GetPartitionBoundariesOlderThanAsync to IAuditLogRepository: a
CROSS APPLY over sys.partition_range_values + per-partition MAX(OccurredAtUtc)
to enumerate retention-eligible months for the M6 purge actor (next commit).
Tests verify:
* Old partition's rows are removed; other months untouched
* UX_AuditLog_EventId is rebuilt after a successful switch
* InsertIfNotExistsAsync's first-write-wins idempotency still holds after switch
* On engineered SWITCH failure (inbound FK from a probe table), SqlException
propagates AND UX_AuditLog_EventId is still present (CATCH branch ran)
* GetPartitionBoundariesOlderThanAsync returns only boundaries whose partition's
MAX(OccurredAtUtc) is strictly older than the threshold; empty partitions
excluded
M4 Bundle B (B1) — add the central-only ICentralAuditWriter implementation
and inject it into NotificationOutboxActor so subsequent tasks (B2/B3) can
route attempt + terminal lifecycle events through the direct-write audit path.
- CentralAuditWriter: thin wrapper around IAuditLogRepository.InsertIfNotExistsAsync;
scope-per-call (matches AuditLogIngestActor / NotificationOutboxActor pattern);
stamps IngestedAtUtc; swallows all internal failures (alog.md §13).
- Registered as a singleton in AddAuditLog.
- NotificationOutboxActor ctor takes ICentralAuditWriter (validated non-null).
- Host wiring resolves the writer once from the root provider and passes it
into the singleton's Props.Create call.
- Existing TestKit fixtures updated with a NoOpCentralAuditWriter helper so
tests that don't exercise audit emission still compile and pass.
