fix(auditlog): page the site audit purge, bound incremental_vacuum per page, fail fast instead of parking writers on a full queue (review 2026-10-21 06/MEM-1)

2026-10-22 06:23:35 -04:00
parent 268b55e350
commit 1da5d0bac4
6 changed files with 261 additions and 56 deletions
@@ -38,9 +38,15 @@ public class SqliteAuditWriterRetentionTests : IDisposable
        }
    }

-    private SqliteAuditWriter CreateWriter()
+    private SqliteAuditWriter CreateWriter(int purgeBatchSize = 5000, int channelCapacity = 4096, int batchSize = 256)
    {
-        var options = new SqliteAuditWriterOptions { DatabasePath = _dbPath };
+        var options = new SqliteAuditWriterOptions
+        {
+            DatabasePath = _dbPath,
+            PurgeBatchSize = purgeBatchSize,
+            ChannelCapacity = channelCapacity,
+            BatchSize = batchSize,
+        };
        return new SqliteAuditWriter(
            Options.Create(options),
            NullLogger<SqliteAuditWriter>.Instance,
@@ -95,4 +101,74 @@ public class SqliteAuditWriterRetentionTests : IDisposable
        Assert.Equal(1, await writer.PurgeExpiredAsync(DateTime.UtcNow.AddDays(-7)));
        Assert.Equal(0, await writer.PurgeExpiredAsync(DateTime.UtcNow.AddDays(-7)));
    }
+
+    /// <summary>
+    /// Review 2026-10-21 06/MEM-1: the purge deletes in bounded pages (one transaction
+    /// each, write lock released between them) and still removes every eligible row.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [Fact]
+    public async Task PurgeExpired_IsPaged_AndStillRemovesEveryEligibleRow()
+    {
+        await using var writer = CreateWriter(purgeBatchSize: 10);
+        var ids = new List<Guid>();
+        for (var i = 0; i < 35; i++)
+        {
+            ids.Add(await WriteEventAsync(writer, DateTime.UtcNow.AddDays(-10)));
+        }
+        var pendingId = await WriteEventAsync(writer, DateTime.UtcNow.AddDays(-10));
+        await writer.MarkForwardedAsync(ids);
+
+        var purged = await writer.PurgeExpiredAsync(DateTime.UtcNow.AddDays(-7));
+
+        Assert.Equal(35, purged);
+        Assert.Equal(4, writer.PurgePageCountForTests); // 10 + 10 + 10 + 5
+        var pending = await writer.ReadPendingAsync(10);
+        Assert.Equal(pendingId, Assert.Single(pending).EventId);
+    }
+
+    /// <summary>
+    /// Review 2026-10-21 06/MEM-1: with the background writer parked (as behind a long purge
+    /// page) and the bounded queue full, <c>WriteAsync</c> must fail fast with
+    /// <see cref="SqliteAuditWriterSaturatedException"/> instead of parking a waiter that
+    /// holds its event for as long as the writer stays stuck.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [Fact]
+    public async Task WriteAsync_QueueFull_FailsFast_InsteadOfParking()
+    {
+        await using var writer = CreateWriter(channelCapacity: 1, batchSize: 1);
+        Task first, third;
+        System.Threading.Monitor.Enter(writer.WriteLockForTests);
+        try
+        {
+            first = writer.WriteAsync(NewEvent());
+            // Wait until the writer loop has dequeued `first` and is blocked on the lock.
+            Assert.True(SpinWait.SpinUntil(() =>
+            {
+                var probe = writer.WriteAsync(NewEvent());
+                if (probe.IsFaulted) { probe.Exception!.Handle(_ => true); return false; }
+                return true;
+            }, TimeSpan.FromSeconds(5)));
+            // The queue (capacity 1) now holds the probe; the next write cannot fit.
+            third = writer.WriteAsync(NewEvent());
+            Assert.True(third.IsFaulted, "a full queue must fault immediately, not park");
+            Assert.IsType<SqliteAuditWriterSaturatedException>(third.Exception!.InnerException);
+            Assert.True(writer.SaturatedRejectionCount >= 1);
+        }
+        finally
+        {
+            System.Threading.Monitor.Exit(writer.WriteLockForTests);
+        }
+
+        // Lock released: the parked writer resumes and the accepted event lands.
+        await first.WaitAsync(TimeSpan.FromSeconds(5));
+    }
+
+    private static AuditEvent NewEvent() => ScadaBridgeAuditEventFactory.Create(
+        eventId: Guid.NewGuid(),
+        occurredAtUtc: DateTime.UtcNow,
+        channel: AuditChannel.ApiOutbound,
+        kind: AuditKind.ApiCall,
+        status: AuditStatus.Delivered);
 }