55fbcce7a8
Adds RingBufferFallback — an in-memory drop-oldest ring buffer used by the upcoming FallbackAuditWriter (Bundle B-T4) when the primary SQLite writer is throwing. Backed by Channel<AuditEvent> with BoundedChannelFullMode.DropOldest, fixed capacity (default 1024). Channel.CreateBounded(DropOldest) does NOT natively signal a drop on TryWrite, so overflow is detected by comparing Reader.Count before and after the enqueue: when the buffer is already at capacity and a new TryWrite succeeds while keeping the count at capacity, exactly one event was displaced and RingBufferOverflowed is raised (one event per drop). Public surface: - bool TryEnqueue(AuditEvent) — always succeeds unless completed. - IAsyncEnumerable<AuditEvent> DrainAsync(CancellationToken) — FIFO. - void Complete() — closes the channel so DrainAsync can finish. - event Action? RingBufferOverflowed — health counter hook. Tests (3 new, total 23 -> 26): - Enqueue_1025_Into_1024Cap_Ring_DropsOldest_AndRaisesOverflowOnce - DrainAsync_Yields_FIFO_Then_Completes_When_Empty - TryEnqueue_AllSucceeds_ReturnsTrue
92 lines
2.7 KiB
C#
92 lines
2.7 KiB
C#
using ScadaLink.AuditLog.Site;
|
|
using ScadaLink.Commons.Entities.Audit;
|
|
using ScadaLink.Commons.Types.Enums;
|
|
|
|
namespace ScadaLink.AuditLog.Tests.Site;
|
|
|
|
/// <summary>
|
|
/// Bundle B (M2-T3) tests for <see cref="RingBufferFallback"/> — the
|
|
/// drop-oldest fallback used by <see cref="FallbackAuditWriter"/> when the
|
|
/// primary SQLite writer is throwing.
|
|
/// </summary>
|
|
public class RingBufferFallbackTests
|
|
{
|
|
private static AuditEvent NewEvent(string? target = null)
|
|
{
|
|
return new AuditEvent
|
|
{
|
|
EventId = Guid.NewGuid(),
|
|
OccurredAtUtc = DateTime.UtcNow,
|
|
Channel = AuditChannel.ApiOutbound,
|
|
Kind = AuditKind.ApiCall,
|
|
Status = AuditStatus.Delivered,
|
|
Target = target,
|
|
PayloadTruncated = false,
|
|
ForwardState = AuditForwardState.Pending,
|
|
};
|
|
}
|
|
|
|
[Fact]
|
|
public async Task Enqueue_1025_Into_1024Cap_Ring_DropsOldest_AndRaisesOverflowOnce()
|
|
{
|
|
var ring = new RingBufferFallback(capacity: 1024);
|
|
var overflowCount = 0;
|
|
ring.RingBufferOverflowed += () => Interlocked.Increment(ref overflowCount);
|
|
|
|
var events = Enumerable.Range(0, 1025).Select(i => NewEvent(target: i.ToString())).ToList();
|
|
foreach (var e in events)
|
|
{
|
|
Assert.True(ring.TryEnqueue(e));
|
|
}
|
|
|
|
Assert.Equal(1, overflowCount);
|
|
|
|
// The surviving 1024 are events[1..1024] (oldest dropped).
|
|
var drained = new List<AuditEvent>();
|
|
ring.Complete();
|
|
await foreach (var e in ring.DrainAsync(CancellationToken.None))
|
|
{
|
|
drained.Add(e);
|
|
}
|
|
|
|
Assert.Equal(1024, drained.Count);
|
|
Assert.Equal("1", drained[0].Target);
|
|
Assert.Equal("1024", drained[^1].Target);
|
|
}
|
|
|
|
[Fact]
|
|
public async Task DrainAsync_Yields_FIFO_Then_Completes_When_Empty()
|
|
{
|
|
var ring = new RingBufferFallback(capacity: 16);
|
|
var enqueued = Enumerable.Range(0, 5).Select(i => NewEvent(target: i.ToString())).ToList();
|
|
foreach (var e in enqueued)
|
|
{
|
|
Assert.True(ring.TryEnqueue(e));
|
|
}
|
|
|
|
ring.Complete();
|
|
|
|
var drained = new List<AuditEvent>();
|
|
await foreach (var e in ring.DrainAsync(CancellationToken.None))
|
|
{
|
|
drained.Add(e);
|
|
}
|
|
|
|
Assert.Equal(5, drained.Count);
|
|
for (int i = 0; i < 5; i++)
|
|
{
|
|
Assert.Equal(i.ToString(), drained[i].Target);
|
|
}
|
|
}
|
|
|
|
[Fact]
|
|
public void TryEnqueue_AllSucceeds_ReturnsTrue()
|
|
{
|
|
var ring = new RingBufferFallback(capacity: 16);
|
|
for (int i = 0; i < 8; i++)
|
|
{
|
|
Assert.True(ring.TryEnqueue(NewEvent()));
|
|
}
|
|
}
|
|
}
|