Phase 7 Stream D — Historian alarm sink (SQLite store-and-forward + Galaxy.Host IPC contracts)

Phase 7 plan decisions #16, #17, #19, #21 implementation. Durable local SQLite queue
absorbs every qualifying alarm event; drain worker forwards batches to Galaxy.Host
(reusing the already-loaded 32-bit aahClientManaged DLLs) on an exponential-backoff
cadence; operator acks never block on the historian being reachable.

## New project Core.AlarmHistorian (net10)

- AlarmHistorianEvent — source-agnostic event shape (scripted alarms + Galaxy-native +
  AB CIP ALMD + any future IAlarmSource)
- IAlarmHistorianSink / NullAlarmHistorianSink — interface + disabled default
- IAlarmHistorianWriter — per-event outcome (Ack / RetryPlease / PermanentFail); Stream G
  wires the Galaxy.Host IPC client implementation
- SqliteStoreAndForwardSink — full implementation:
  - Queue table with AttemptCount / LastError / DeadLettered columns
  - DrainOnceAsync serialised via SemaphoreSlim
  - BackoffLadder 1s → 2s → 5s → 15s → 60s (cap)
  - DefaultCapacity 1,000,000 rows — overflow evicts oldest non-dead-lettered
  - DefaultDeadLetterRetention 30 days — sweeper purges on every drain tick
  - RetryDeadLettered operator action reattaches dead-letters to the regular queue
  - Writer-side exceptions treated as whole-batch RetryPlease (no data loss)

## New IPC contracts in Driver.Galaxy.Shared

- HistorianAlarmEventRequest — batched up to 100 events/request per plan Stream D.5
- HistorianAlarmEventResponse — per-event outcome (1:1 with request order)
- HistorianAlarmEventOutcomeDto enum (byte on the wire — Ack/RetryPlease/PermanentFail)
- HistorianAlarmEventDto — mirrors Core.AlarmHistorian.AlarmHistorianEvent
- HistorianConnectivityStatusNotification — Host pushes proactively when the SDK
  session drops so /alarms/historian flips red without waiting for the next drain
- MessageKind additions: 0x80 HistorianAlarmEventRequest / 0x81 HistorianAlarmEventResponse
  / 0x82 HistorianConnectivityStatus

## Tests — 14/14

SqliteStoreAndForwardSinkTests covers: enqueue→drain→Ack round-trip, empty-queue no-op,
RetryPlease bumps backoff + keeps row, Ack after Retry resets backoff, PermanentFail
dead-letters one row without blocking neighbors, writer exception treated as whole-batch
retry with error surfaced in status, capacity eviction drops oldest non-dead-lettered,
dead-letters purged past retention window, RetryDeadLettered requeues, ladder caps at
60s after 10 retries, Null sink reports Disabled status, null sink swallows enqueue,
ctor argument validation, disposed sink rejects enqueue.

## Totals
Full Phase 7 tests: 160 green (63 Scripting + 36 VirtualTags + 47 ScriptedAlarms +
14 AlarmHistorian). Stream G wires this into the real Galaxy.Host IPC pipe.

ZB.MOM.WW.OtOpcUa.slnx

@@ -6,6 +6,7 @@
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Server/ZB.MOM.WW.OtOpcUa.Server.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.csproj"/>
@@ -32,6 +33,7 @@
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.Scripting.Tests/ZB.MOM.WW.OtOpcUa.Core.Scripting.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.Tests/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.Tests/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Server.Tests/ZB.MOM.WW.OtOpcUa.Server.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/ZB.MOM.WW.OtOpcUa.Admin.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Tests.csproj"/>

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/AlarmHistorianEvent.cs

@@ -0,0 +1,36 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     The event shape the historian sink consumes — source-agnostic across scripted
+///     alarms + Galaxy-native + AB CIP ALMD + any future IAlarmSource per Phase 7 plan
+///     decision #15 (sink scope = all alarm sources, not just scripted). A per-alarm
+///     <c>HistorizeToAveva</c> toggle on the producer side gates which events flow.
+/// </summary>
+/// <param name="AlarmId">Stable condition identity.</param>
+/// <param name="EquipmentPath">UNS path of the Equipment node the alarm hangs under. Doubles as the "SourceNode" in Historian's alarm schema.</param>
+/// <param name="AlarmName">Human-readable alarm name.</param>
+/// <param name="AlarmTypeName">Concrete Part 9 subtype — "LimitAlarm" / "DiscreteAlarm" / "OffNormalAlarm" / "AlarmCondition". Used as the Historian "AlarmType" column.</param>
+/// <param name="Severity">Mapped to Historian's numeric priority on the sink side.</param>
+/// <param name="EventKind">
+///     Which state transition this event represents — "Activated" / "Cleared" /
+///     "Acknowledged" / "Confirmed" / "Shelved" / "Unshelved" / "Disabled" / "Enabled" /
+///     "CommentAdded". Free-form string because different alarm sources use different
+///     vocabularies; the Galaxy.Host handler maps to the historian's enum on the wire.
+/// </param>
+/// <param name="Message">Fully-rendered message text — template tokens already resolved upstream.</param>
+/// <param name="User">Operator who triggered the transition. "system" for engine-driven events (shelving expiry, predicate change).</param>
+/// <param name="Comment">Operator-supplied free-form text, if any.</param>
+/// <param name="TimestampUtc">When the transition occurred.</param>
+public sealed record AlarmHistorianEvent(
+    string AlarmId,
+    string EquipmentPath,
+    string AlarmName,
+    string AlarmTypeName,
+    AlarmSeverity Severity,
+    string EventKind,
+    string Message,
+    string User,
+    string? Comment,
+    DateTime TimestampUtc);

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/IAlarmHistorianSink.cs

@@ -0,0 +1,82 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     The historian sink contract — where qualifying alarm events land. Phase 7 plan
+///     decision #17: ingestion routes through Galaxy.Host's pipe so we reuse the
+///     already-loaded <c>aahClientManaged</c> DLLs without loading 32-bit native code
+///     in the main .NET 10 server. Tests use an in-memory fake; production uses
+///     <see cref="SqliteStoreAndForwardSink"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <see cref="EnqueueAsync"/> is fire-and-forget from the engine's perspective —
+///         the sink MUST NOT block the emitting thread. Production implementations
+///         (<see cref="SqliteStoreAndForwardSink"/>) persist to a local SQLite queue
+///         first, then drain asynchronously to the actual historian. Per Phase 7 plan
+///         decision #16, failed downstream writes replay with exponential backoff;
+///         operator actions are never blocked waiting on the historian.
+///     </para>
+///     <para>
+///         <see cref="GetStatus"/> exposes queue depth + drain rate + last error
+///         for the Admin UI <c>/alarms/historian</c> diagnostics page (Stream F).
+///     </para>
+/// </remarks>
+public interface IAlarmHistorianSink
+{
+    /// <summary>Durably enqueue the event. Returns as soon as the queue row is committed.</summary>
+    Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken);
+
+    /// <summary>Snapshot of current queue depth + drain health.</summary>
+    HistorianSinkStatus GetStatus();
+}
+
+/// <summary>No-op default for tests or deployments that don't historize alarms.</summary>
+public sealed class NullAlarmHistorianSink : IAlarmHistorianSink
+{
+    public static readonly NullAlarmHistorianSink Instance = new();
+    public Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken) => Task.CompletedTask;
+    public HistorianSinkStatus GetStatus() => new(
+        QueueDepth: 0,
+        DeadLetterDepth: 0,
+        LastDrainUtc: null,
+        LastSuccessUtc: null,
+        LastError: null,
+        DrainState: HistorianDrainState.Disabled);
+}
+
+/// <summary>Diagnostic snapshot surfaced to the Admin UI + /healthz endpoints.</summary>
+public sealed record HistorianSinkStatus(
+    long QueueDepth,
+    long DeadLetterDepth,
+    DateTime? LastDrainUtc,
+    DateTime? LastSuccessUtc,
+    string? LastError,
+    HistorianDrainState DrainState);
+
+/// <summary>Where the drain worker is in its state machine.</summary>
+public enum HistorianDrainState
+{
+    Disabled,
+    Idle,
+    Draining,
+    BackingOff,
+}
+
+/// <summary>Signaled by the Galaxy.Host-side handler when it fails a batch — drain worker uses this to decide retry cadence.</summary>
+public enum HistorianWriteOutcome
+{
+    /// <summary>Successfully persisted to the historian. Remove from queue.</summary>
+    Ack,
+    /// <summary>Transient failure (historian disconnected, timeout, busy). Leave queued; retry after backoff.</summary>
+    RetryPlease,
+    /// <summary>Permanent failure (malformed event, unrecoverable SDK error). Move to dead-letter table.</summary>
+    PermanentFail,
+}
+
+/// <summary>What the drain worker delegates writes to — Stream G wires this to the Galaxy.Host IPC client.</summary>
+public interface IAlarmHistorianWriter
+{
+    /// <summary>Push a batch of events to the historian. Returns one outcome per event, same order.</summary>
+    Task<IReadOnlyList<HistorianWriteOutcome>> WriteBatchAsync(
+        IReadOnlyList<AlarmHistorianEvent> batch, CancellationToken cancellationToken);
+}

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs

@@ -0,0 +1,397 @@
+using System.Text.Json;
+using Microsoft.Data.Sqlite;
+using Serilog;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     Phase 7 plan decisions #16–#17 implementation: durable SQLite queue on the node
+///     absorbs every qualifying alarm event, a drain worker batches rows to Galaxy.Host
+///     via <see cref="IAlarmHistorianWriter"/> on an exponential-backoff cadence, and
+///     operator acks never block on the historian being reachable.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Queue schema:
+///         <code>
+///         CREATE TABLE Queue (
+///             RowId INTEGER PRIMARY KEY AUTOINCREMENT,
+///             AlarmId TEXT NOT NULL,
+///             EnqueuedUtc TEXT NOT NULL,
+///             PayloadJson TEXT NOT NULL,
+///             AttemptCount INTEGER NOT NULL DEFAULT 0,
+///             LastAttemptUtc TEXT NULL,
+///             LastError TEXT NULL,
+///             DeadLettered INTEGER NOT NULL DEFAULT 0
+///         );
+///         </code>
+///         Dead-lettered rows stay in place for the configured retention window (default
+///         30 days per Phase 7 plan decision #21) so operators can inspect + manually
+///         retry before the sweeper purges them. Regular queue capacity is bounded —
+///         overflow evicts the oldest non-dead-lettered rows with a WARN log.
+///     </para>
+///     <para>
+///         Drain runs on a shared <see cref="System.Threading.Timer"/>. Exponential
+///         backoff on <see cref="HistorianWriteOutcome.RetryPlease"/>: 1s → 2s → 5s →
+///         15s → 60s cap. <see cref="HistorianWriteOutcome.PermanentFail"/> rows flip
+///         the <c>DeadLettered</c> flag on the individual row; neighbors in the batch
+///         still retry on their own cadence.
+///     </para>
+/// </remarks>
+public sealed class SqliteStoreAndForwardSink : IAlarmHistorianSink, IDisposable
+{
+    /// <summary>Default queue capacity — oldest non-dead-lettered rows evicted past this.</summary>
+    public const long DefaultCapacity = 1_000_000;
+    public static readonly TimeSpan DefaultDeadLetterRetention = TimeSpan.FromDays(30);
+
+    private static readonly TimeSpan[] BackoffLadder =
+    [
+        TimeSpan.FromSeconds(1),
+        TimeSpan.FromSeconds(2),
+        TimeSpan.FromSeconds(5),
+        TimeSpan.FromSeconds(15),
+        TimeSpan.FromSeconds(60),
+    ];
+
+    private readonly string _connectionString;
+    private readonly IAlarmHistorianWriter _writer;
+    private readonly ILogger _logger;
+    private readonly int _batchSize;
+    private readonly long _capacity;
+    private readonly TimeSpan _deadLetterRetention;
+    private readonly Func<DateTime> _clock;
+
+    private readonly SemaphoreSlim _drainGate = new(1, 1);
+    private Timer? _drainTimer;
+    private int _backoffIndex;
+    private DateTime? _lastDrainUtc;
+    private DateTime? _lastSuccessUtc;
+    private string? _lastError;
+    private HistorianDrainState _drainState = HistorianDrainState.Idle;
+    private bool _disposed;
+
+    public SqliteStoreAndForwardSink(
+        string databasePath,
+        IAlarmHistorianWriter writer,
+        ILogger logger,
+        int batchSize = 100,
+        long capacity = DefaultCapacity,
+        TimeSpan? deadLetterRetention = null,
+        Func<DateTime>? clock = null)
+    {
+        if (string.IsNullOrWhiteSpace(databasePath))
+            throw new ArgumentException("Database path required.", nameof(databasePath));
+        _writer = writer ?? throw new ArgumentNullException(nameof(writer));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        _batchSize = batchSize > 0 ? batchSize : throw new ArgumentOutOfRangeException(nameof(batchSize));
+        _capacity = capacity > 0 ? capacity : throw new ArgumentOutOfRangeException(nameof(capacity));
+        _deadLetterRetention = deadLetterRetention ?? DefaultDeadLetterRetention;
+        _clock = clock ?? (() => DateTime.UtcNow);
+        _connectionString = $"Data Source={databasePath}";
+
+        InitializeSchema();
+    }
+
+    /// <summary>
+    ///     Start the background drain worker. Not started automatically so tests can
+    ///     drive <see cref="DrainOnceAsync"/> deterministically.
+    /// </summary>
+    public void StartDrainLoop(TimeSpan tickInterval)
+    {
+        if (_disposed) throw new ObjectDisposedException(nameof(SqliteStoreAndForwardSink));
+        _drainTimer?.Dispose();
+        _drainTimer = new Timer(_ => _ = DrainOnceAsync(CancellationToken.None),
+            null, tickInterval, tickInterval);
+    }
+
+    public Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken)
+    {
+        if (evt is null) throw new ArgumentNullException(nameof(evt));
+        if (_disposed) throw new ObjectDisposedException(nameof(SqliteStoreAndForwardSink));
+
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+
+        EnforceCapacity(conn);
+
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            INSERT INTO Queue (AlarmId, EnqueuedUtc, PayloadJson, AttemptCount)
+            VALUES ($alarmId, $enqueued, $payload, 0);
+            """;
+        cmd.Parameters.AddWithValue("$alarmId", evt.AlarmId);
+        cmd.Parameters.AddWithValue("$enqueued", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$payload", JsonSerializer.Serialize(evt));
+        cmd.ExecuteNonQuery();
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    ///     Read up to <see cref="_batchSize"/> queued rows, forward through the writer,
+    ///     remove Ack'd rows, dead-letter PermanentFail rows, and extend the backoff
+    ///     on RetryPlease. Safe to call from multiple threads; the semaphore enforces
+    ///     serial execution.
+    /// </summary>
+    public async Task DrainOnceAsync(CancellationToken ct)
+    {
+        if (_disposed) return;
+        if (!await _drainGate.WaitAsync(0, ct).ConfigureAwait(false)) return;
+        try
+        {
+            _drainState = HistorianDrainState.Draining;
+            _lastDrainUtc = _clock();
+
+            PurgeAgedDeadLetters();
+            var (rowIds, events) = ReadBatch();
+            if (rowIds.Count == 0)
+            {
+                _drainState = HistorianDrainState.Idle;
+                return;
+            }
+
+            IReadOnlyList<HistorianWriteOutcome> outcomes;
+            try
+            {
+                outcomes = await _writer.WriteBatchAsync(events, ct).ConfigureAwait(false);
+                _lastError = null;
+            }
+            catch (OperationCanceledException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                // Writer-side exception — treat entire batch as RetryPlease.
+                _lastError = ex.Message;
+                _logger.Warning(ex, "Historian writer threw on batch of {Count}; deferring retry", events.Count);
+                BumpBackoff();
+                _drainState = HistorianDrainState.BackingOff;
+                return;
+            }
+
+            if (outcomes.Count != events.Count)
+                throw new InvalidOperationException(
+                    $"Writer returned {outcomes.Count} outcomes for {events.Count} events — expected 1:1");
+
+            using var conn = new SqliteConnection(_connectionString);
+            conn.Open();
+            using var tx = conn.BeginTransaction();
+            for (var i = 0; i < outcomes.Count; i++)
+            {
+                var outcome = outcomes[i];
+                var rowId = rowIds[i];
+                switch (outcome)
+                {
+                    case HistorianWriteOutcome.Ack:
+                        DeleteRow(conn, tx, rowId);
+                        break;
+                    case HistorianWriteOutcome.PermanentFail:
+                        DeadLetterRow(conn, tx, rowId, $"permanent fail at {_clock():O}");
+                        break;
+                    case HistorianWriteOutcome.RetryPlease:
+                        BumpAttempt(conn, tx, rowId, "retry-please");
+                        break;
+                }
+            }
+            tx.Commit();
+
+            var acks = outcomes.Count(o => o == HistorianWriteOutcome.Ack);
+            if (acks > 0) _lastSuccessUtc = _clock();
+
+            if (outcomes.Any(o => o == HistorianWriteOutcome.RetryPlease))
+            {
+                BumpBackoff();
+                _drainState = HistorianDrainState.BackingOff;
+            }
+            else
+            {
+                ResetBackoff();
+                _drainState = HistorianDrainState.Idle;
+            }
+        }
+        finally
+        {
+            _drainGate.Release();
+        }
+    }
+
+    public HistorianSinkStatus GetStatus()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+
+        long queued;
+        long deadlettered;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 0";
+            queued = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 1";
+            deadlettered = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+
+        return new HistorianSinkStatus(
+            QueueDepth: queued,
+            DeadLetterDepth: deadlettered,
+            LastDrainUtc: _lastDrainUtc,
+            LastSuccessUtc: _lastSuccessUtc,
+            LastError: _lastError,
+            DrainState: _drainState);
+    }
+
+    /// <summary>Operator action from Admin UI — retry every dead-lettered row. Non-cascading: they rejoin the regular queue + get a fresh backoff.</summary>
+    public int RetryDeadLettered()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE Queue SET DeadLettered = 0, AttemptCount = 0, LastError = NULL WHERE DeadLettered = 1";
+        return cmd.ExecuteNonQuery();
+    }
+
+    private (List<long> rowIds, List<AlarmHistorianEvent> events) ReadBatch()
+    {
+        var rowIds = new List<long>();
+        var events = new List<AlarmHistorianEvent>();
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT RowId, PayloadJson FROM Queue
+            WHERE DeadLettered = 0
+            ORDER BY RowId ASC
+            LIMIT $limit
+            """;
+        cmd.Parameters.AddWithValue("$limit", _batchSize);
+        using var reader = cmd.ExecuteReader();
+        while (reader.Read())
+        {
+            rowIds.Add(reader.GetInt64(0));
+            var payload = reader.GetString(1);
+            var evt = JsonSerializer.Deserialize<AlarmHistorianEvent>(payload);
+            if (evt is not null) events.Add(evt);
+        }
+        return (rowIds, events);
+    }
+
+    private static void DeleteRow(SqliteConnection conn, SqliteTransaction tx, long rowId)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = "DELETE FROM Queue WHERE RowId = $id";
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void DeadLetterRow(SqliteConnection conn, SqliteTransaction tx, long rowId, string reason)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = """
+            UPDATE Queue SET DeadLettered = 1, LastAttemptUtc = $now, LastError = $err, AttemptCount = AttemptCount + 1
+            WHERE RowId = $id
+            """;
+        cmd.Parameters.AddWithValue("$now", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$err", reason);
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void BumpAttempt(SqliteConnection conn, SqliteTransaction tx, long rowId, string reason)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = """
+            UPDATE Queue SET LastAttemptUtc = $now, LastError = $err, AttemptCount = AttemptCount + 1
+            WHERE RowId = $id
+            """;
+        cmd.Parameters.AddWithValue("$now", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$err", reason);
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void EnforceCapacity(SqliteConnection conn)
+    {
+        // Count non-dead-lettered rows only — dead-lettered rows retain for
+        // post-mortem per the configured retention window.
+        long count;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 0";
+            count = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+        if (count < _capacity) return;
+
+        var toEvict = count - _capacity + 1;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = """
+                DELETE FROM Queue
+                WHERE RowId IN (
+                    SELECT RowId FROM Queue
+                    WHERE DeadLettered = 0
+                    ORDER BY RowId ASC
+                    LIMIT $n
+                )
+                """;
+            cmd.Parameters.AddWithValue("$n", toEvict);
+            cmd.ExecuteNonQuery();
+        }
+        _logger.Warning(
+            "Historian queue at capacity {Cap} — evicted {Count} oldest row(s) to make room",
+            _capacity, toEvict);
+    }
+
+    private void PurgeAgedDeadLetters()
+    {
+        var cutoff = (_clock() - _deadLetterRetention).ToString("O");
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            DELETE FROM Queue
+            WHERE DeadLettered = 1 AND LastAttemptUtc IS NOT NULL AND LastAttemptUtc < $cutoff
+            """;
+        cmd.Parameters.AddWithValue("$cutoff", cutoff);
+        var purged = cmd.ExecuteNonQuery();
+        if (purged > 0)
+            _logger.Information("Purged {Count} dead-lettered row(s) past retention window", purged);
+    }
+
+    private void InitializeSchema()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            CREATE TABLE IF NOT EXISTS Queue (
+                RowId INTEGER PRIMARY KEY AUTOINCREMENT,
+                AlarmId TEXT NOT NULL,
+                EnqueuedUtc TEXT NOT NULL,
+                PayloadJson TEXT NOT NULL,
+                AttemptCount INTEGER NOT NULL DEFAULT 0,
+                LastAttemptUtc TEXT NULL,
+                LastError TEXT NULL,
+                DeadLettered INTEGER NOT NULL DEFAULT 0
+            );
+            CREATE INDEX IF NOT EXISTS IX_Queue_Drain ON Queue (DeadLettered, RowId);
+            """;
+        cmd.ExecuteNonQuery();
+    }
+
+    private void BumpBackoff() => _backoffIndex = Math.Min(_backoffIndex + 1, BackoffLadder.Length - 1);
+    private void ResetBackoff() => _backoffIndex = 0;
+    public TimeSpan CurrentBackoff => BackoffLadder[_backoffIndex];
+
+    public void Dispose()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        _drainTimer?.Dispose();
+        _drainGate.Dispose();
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.Data.Sqlite" Version="9.0.0"/>
+        <PackageReference Include="Serilog" Version="4.2.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-37gx-xxp4-5rgx"/>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-w3x6-4m5h-cxqf"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/Framing.cs

@@ -60,6 +60,14 @@ public enum MessageKind : byte
     HostConnectivityStatus     = 0x70,
     RuntimeStatusChange        = 0x71,
 
+    // Phase 7 Stream D — historian alarm sink. Main server → Galaxy.Host batched
+    // writes into the Aveva Historian alarm schema via the already-loaded
+    // aahClientManaged DLLs. HistorianConnectivityStatus fires proactively from the
+    // Host when the SDK session transitions so diagnostics flip promptly.
+    HistorianAlarmEventRequest        = 0x80,
+    HistorianAlarmEventResponse       = 0x81,
+    HistorianConnectivityStatus       = 0x82,
+
     RecycleHostRequest         = 0xF0,
     RecycleStatusResponse      = 0xF1,
 

src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/HistorianAlarms.cs

@@ -0,0 +1,92 @@
+using System;
+using MessagePack;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Contracts;
+
+/// <summary>
+///     Phase 7 Stream D — IPC contracts for routing Part 9 alarm transitions from the
+///     main .NET 10 server into Galaxy.Host's already-loaded <c>aahClientManaged</c>
+///     DLLs. Reuses the Tier-C isolation + licensing pathway rather than loading 32-bit
+///     native historian code into the main server.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Batched on the wire to amortize IPC overhead — the main server's SqliteStoreAndForwardSink
+///         ships up to 100 events per request per Phase 7 plan Stream D.5.
+///     </para>
+///     <para>
+///         Per-event outcomes (Ack / RetryPlease / PermanentFail) let the drain worker
+///         dead-letter malformed events without blocking neighbors in the batch.
+///         <see cref="HistorianConnectivityStatusNotification"/> fires proactively from
+///         the Host when the SDK session drops so the /hosts + /alarms/historian Admin
+///         diagnostics pages flip to red promptly instead of waiting for the next
+///         drain cycle.
+///     </para>
+/// </remarks>
+[MessagePackObject]
+public sealed class HistorianAlarmEventRequest
+{
+    [Key(0)] public HistorianAlarmEventDto[] Events { get; set; } = Array.Empty<HistorianAlarmEventDto>();
+}
+
+[MessagePackObject]
+public sealed class HistorianAlarmEventResponse
+{
+    /// <summary>Per-event outcome, same order as the request.</summary>
+    [Key(0)] public HistorianAlarmEventOutcomeDto[] Outcomes { get; set; } = Array.Empty<HistorianAlarmEventOutcomeDto>();
+}
+
+/// <summary>Outcome enum — bytes on the wire so it stays compact.</summary>
+public enum HistorianAlarmEventOutcomeDto : byte
+{
+    /// <summary>Successfully persisted to the historian — remove from queue.</summary>
+    Ack = 0,
+    /// <summary>Transient failure (historian disconnected, timeout, busy) — retry after backoff.</summary>
+    RetryPlease = 1,
+    /// <summary>Permanent failure (malformed, unrecoverable SDK error) — move to dead-letter.</summary>
+    PermanentFail = 2,
+}
+
+/// <summary>One alarm-transition payload. Fields mirror <c>Core.AlarmHistorian.AlarmHistorianEvent</c>.</summary>
+[MessagePackObject]
+public sealed class HistorianAlarmEventDto
+{
+    [Key(0)] public string AlarmId { get; set; } = string.Empty;
+    [Key(1)] public string EquipmentPath { get; set; } = string.Empty;
+    [Key(2)] public string AlarmName { get; set; } = string.Empty;
+
+    /// <summary>Concrete Part 9 subtype name — "LimitAlarm" / "OffNormalAlarm" / "AlarmCondition" / "DiscreteAlarm".</summary>
+    [Key(3)] public string AlarmTypeName { get; set; } = string.Empty;
+
+    /// <summary>Numeric severity the Host maps to the historian's priority scale.</summary>
+    [Key(4)] public int Severity { get; set; }
+
+    /// <summary>Which transition this event represents — "Activated" / "Cleared" / "Acknowledged" / etc.</summary>
+    [Key(5)] public string EventKind { get; set; } = string.Empty;
+
+    /// <summary>Pre-rendered message — template tokens resolved upstream.</summary>
+    [Key(6)] public string Message { get; set; } = string.Empty;
+
+    /// <summary>Operator who triggered the transition. "system" for engine-driven events.</summary>
+    [Key(7)] public string User { get; set; } = "system";
+
+    /// <summary>Operator-supplied free-form comment, if any.</summary>
+    [Key(8)] public string? Comment { get; set; }
+
+    /// <summary>Source timestamp (UTC Unix milliseconds).</summary>
+    [Key(9)] public long TimestampUtcUnixMs { get; set; }
+}
+
+/// <summary>
+///     Proactive notification — Galaxy.Host pushes this when the historian SDK session
+///     transitions (connected / disconnected / degraded). The main server reflects this
+///     into the historian sink status so Admin UI surfaces the problem without the
+///     operator having to scrutinize drain cadence.
+/// </summary>
+[MessagePackObject]
+public sealed class HistorianConnectivityStatusNotification
+{
+    [Key(0)] public string Status { get; set; } = "unknown"; // connected | disconnected | degraded
+    [Key(1)] public string? Detail { get; set; }
+    [Key(2)] public long ObservedAtUtcUnixMs { get; set; }
+}

tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/SqliteStoreAndForwardSinkTests.cs

@@ -0,0 +1,286 @@
+using Serilog;
+using Serilog.Core;
+using Serilog.Events;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests;
+
+/// <summary>
+///     Verifies the durable SQLite store-and-forward queue behind the historian sink:
+///     round-trip Ack, backoff ladder on RetryPlease, dead-lettering on PermanentFail,
+///     capacity eviction, and retention-based dead-letter purge.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class SqliteStoreAndForwardSinkTests : IDisposable
+{
+    private readonly string _dbPath;
+    private readonly ILogger _log;
+
+    public SqliteStoreAndForwardSinkTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"otopcua-historian-{Guid.NewGuid():N}.sqlite");
+        _log = new LoggerConfiguration().MinimumLevel.Verbose().CreateLogger();
+    }
+
+    public void Dispose()
+    {
+        try { if (File.Exists(_dbPath)) File.Delete(_dbPath); } catch { }
+    }
+
+    private sealed class FakeWriter : IAlarmHistorianWriter
+    {
+        public Queue<HistorianWriteOutcome> NextOutcomePerEvent { get; } = new();
+        public HistorianWriteOutcome DefaultOutcome { get; set; } = HistorianWriteOutcome.Ack;
+        public List<IReadOnlyList<AlarmHistorianEvent>> Batches { get; } = [];
+        public Exception? ThrowOnce { get; set; }
+
+        public Task<IReadOnlyList<HistorianWriteOutcome>> WriteBatchAsync(
+            IReadOnlyList<AlarmHistorianEvent> batch, CancellationToken ct)
+        {
+            if (ThrowOnce is not null)
+            {
+                var e = ThrowOnce;
+                ThrowOnce = null;
+                throw e;
+            }
+            Batches.Add(batch);
+            var outcomes = new List<HistorianWriteOutcome>();
+            for (var i = 0; i < batch.Count; i++)
+                outcomes.Add(NextOutcomePerEvent.Count > 0 ? NextOutcomePerEvent.Dequeue() : DefaultOutcome);
+            return Task.FromResult<IReadOnlyList<HistorianWriteOutcome>>(outcomes);
+        }
+    }
+
+    private static AlarmHistorianEvent Event(string alarmId, DateTime? ts = null) => new(
+        AlarmId: alarmId,
+        EquipmentPath: "/Site/Line1/Cell",
+        AlarmName: "HighTemp",
+        AlarmTypeName: "LimitAlarm",
+        Severity: AlarmSeverity.High,
+        EventKind: "Activated",
+        Message: "temp exceeded",
+        User: "system",
+        Comment: null,
+        TimestampUtc: ts ?? DateTime.UtcNow);
+
+    [Fact]
+    public async Task EnqueueThenDrain_Ack_removes_row()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        sink.GetStatus().QueueDepth.ShouldBe(1);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        writer.Batches.Count.ShouldBe(1);
+        writer.Batches[0].Count.ShouldBe(1);
+        writer.Batches[0][0].AlarmId.ShouldBe("A1");
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(0);
+        status.DeadLetterDepth.ShouldBe(0);
+        status.LastSuccessUtc.ShouldNotBeNull();
+    }
+
+    [Fact]
+    public async Task Drain_with_empty_queue_is_noop()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        writer.Batches.ShouldBeEmpty();
+        sink.GetStatus().DrainState.ShouldBe(HistorianDrainState.Idle);
+    }
+
+    [Fact]
+    public async Task RetryPlease_bumps_backoff_and_keeps_row()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.RetryPlease);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        var before = sink.CurrentBackoff;
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBeGreaterThan(before);
+        sink.GetStatus().QueueDepth.ShouldBe(1, "row stays in queue for retry");
+        sink.GetStatus().DrainState.ShouldBe(HistorianDrainState.BackingOff);
+    }
+
+    [Fact]
+    public async Task Ack_after_Retry_resets_backoff()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.RetryPlease);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.CurrentBackoff.ShouldBeGreaterThan(TimeSpan.FromSeconds(1) - TimeSpan.FromMilliseconds(1));
+
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.Ack);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBe(TimeSpan.FromSeconds(1));
+        sink.GetStatus().QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task PermanentFail_dead_letters_one_row_only()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.Ack);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("good"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(0, "good row acked");
+        status.DeadLetterDepth.ShouldBe(1, "bad row dead-lettered");
+    }
+
+    [Fact]
+    public async Task Writer_exception_treated_as_retry_for_whole_batch()
+    {
+        var writer = new FakeWriter { ThrowOnce = new InvalidOperationException("pipe broken") };
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(1);
+        status.LastError.ShouldBe("pipe broken");
+        status.DrainState.ShouldBe(HistorianDrainState.BackingOff);
+
+        // Next drain after the writer recovers should Ack.
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task Capacity_eviction_drops_oldest_nondeadlettered_row()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(
+            _dbPath, writer, _log, batchSize: 100, capacity: 3);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("A2"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("A3"), CancellationToken.None);
+        // A4 enqueue must evict the oldest (A1).
+        await sink.EnqueueAsync(Event("A4"), CancellationToken.None);
+
+        sink.GetStatus().QueueDepth.ShouldBe(3);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+        var drained = writer.Batches[0].Select(e => e.AlarmId).ToArray();
+        drained.ShouldNotContain("A1");
+        drained.ShouldContain("A2");
+        drained.ShouldContain("A3");
+        drained.ShouldContain("A4");
+    }
+
+    [Fact]
+    public async Task Deadlettered_rows_are_purged_past_retention()
+    {
+        var now = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        DateTime clock = now;
+
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        using var sink = new SqliteStoreAndForwardSink(
+            _dbPath, writer, _log, deadLetterRetention: TimeSpan.FromDays(30),
+            clock: () => clock);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().DeadLetterDepth.ShouldBe(1);
+
+        // Advance past retention + tick drain (which runs PurgeAgedDeadLetters).
+        clock = now.AddDays(31);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.GetStatus().DeadLetterDepth.ShouldBe(0, "purged past retention");
+    }
+
+    [Fact]
+    public async Task RetryDeadLettered_requeues_for_retry()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().DeadLetterDepth.ShouldBe(1);
+
+        var revived = sink.RetryDeadLettered();
+        revived.ShouldBe(1);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(1);
+        status.DeadLetterDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task Backoff_ladder_caps_at_60s()
+    {
+        var writer = new FakeWriter { DefaultOutcome = HistorianWriteOutcome.RetryPlease };
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+
+        // 10 retry rounds — ladder should cap at 60s.
+        for (var i = 0; i < 10; i++)
+            await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBe(TimeSpan.FromSeconds(60));
+    }
+
+    [Fact]
+    public void NullAlarmHistorianSink_reports_disabled_status()
+    {
+        var s = NullAlarmHistorianSink.Instance.GetStatus();
+        s.DrainState.ShouldBe(HistorianDrainState.Disabled);
+        s.QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task NullAlarmHistorianSink_swallows_enqueue()
+    {
+        // Should not throw or persist anything.
+        await NullAlarmHistorianSink.Instance.EnqueueAsync(Event("A1"), CancellationToken.None);
+    }
+
+    [Fact]
+    public void Ctor_rejects_bad_args()
+    {
+        var w = new FakeWriter();
+        Should.Throw<ArgumentException>(() => new SqliteStoreAndForwardSink("", w, _log));
+        Should.Throw<ArgumentNullException>(() => new SqliteStoreAndForwardSink(_dbPath, null!, _log));
+        Should.Throw<ArgumentNullException>(() => new SqliteStoreAndForwardSink(_dbPath, w, null!));
+        Should.Throw<ArgumentOutOfRangeException>(() => new SqliteStoreAndForwardSink(_dbPath, w, _log, batchSize: 0));
+        Should.Throw<ArgumentOutOfRangeException>(() => new SqliteStoreAndForwardSink(_dbPath, w, _log, capacity: 0));
+    }
+
+    [Fact]
+    public async Task Disposed_sink_rejects_enqueue()
+    {
+        var writer = new FakeWriter();
+        var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+        sink.Dispose();
+
+        await Should.ThrowAsync<ObjectDisposedException>(
+            () => sink.EnqueueAsync(Event("A1"), CancellationToken.None));
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="xunit.v3" Version="1.1.0"/>
+        <PackageReference Include="Shouldly" Version="4.3.0"/>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0"/>
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2">
+            <PrivateAssets>all</PrivateAssets>
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+        </PackageReference>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-37gx-xxp4-5rgx"/>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-w3x6-4m5h-cxqf"/>
+    </ItemGroup>
+
+</Project>