Files
ScadaBridge/tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/Actors/DataConnectionActorBatchTests.cs
T
Joseph Doherty 491df111ea fix(dcl): derive tag-resolution health counts from per-tag authoritative state
Closes arch-review remediation residual #1 (DCL unsubscribe-during-reconnect
count staleness).

DataConnectionActor tracked TotalSubscribedTags/ResolvedTags as two int fields
incremented and decremented at five independent sites. ReSubscribeAll clears the
very maps those decrements key off (_subscriptionIds, _unresolvedTags) while
deliberately preserving _subscriptionsByInstance, so an unsubscribe landing
inside a reconnect window matched NEITHER decrement branch: the total leaked +1
per subscribe/reconnect/unsubscribe churn cycle, permanently and cumulatively.
The 37f13e2e discard gate stopped the orphan-handle half of that race; it could
not stop the counters drifting, because they were state of their own.

Both counts are now DERIVED at report time from the authoritative per-tag
collections, which makes the drift unrepresentable rather than merely guarded:

  total    = _instancesByTag.Count   (the per-tag counted set the residual
                                      called for — distinct tags with at least
                                      one subscribing instance)
  resolved = _subscriptionIds.Count  (tags for which the adapter holds a handle)

Two semantic corrections fall out of the derivation:

- A tag whose subscribe failed at CONNECTION level now counts toward the total.
  It was excluded before, yet the reconnect re-subscribe re-issued it from
  _subscriptionsByInstance and booked it as resolved — resolved above total, and
  a total driven negative by the eventual unsubscribe.
- _tagSubscriberCount is deleted. It duplicated _instancesByTag exactly, so
  HandleUnsubscribe's last-subscriber test is now "did UnindexTag drop the key?"
  — still O(1), with no parallel count that can disagree about when a handle is
  released. The subscribe-success promotion split (fresh vs. unresolved→resolved)
  also goes: it existed only to pick which scalar to bump; set sizes get
  DataConnectionLayer-020's double-count cases right for free.

Behavior is otherwise unchanged — same logging, same handle release, same
unresolved-tag probing, same in-flight-unsubscribe discard semantics (the long
comment block there is updated for the mechanics that changed).

Tests: five TagResolutionCounts_* cases in DataConnectionActorBatchTests
covering the churn repro (3 cycles), a shared tag losing one instance mid
reconnect, connection-level failure then recovery, plain subscribe/unsubscribe
cycles, and a completed reconnect re-subscribe. Verified failing against the
pre-fix actor (churn: total 1 not 0; connection-level: total 0 not 1) and
passing after. Full DCL suite 319/319; solution builds with 0 warnings.

Docs: Component-DataConnectionLayer.md health-reporting section describes the
derived counts; residuals register item 1 marked RESOLVED.
2026-08-15 02:05:35 -04:00

665 lines
32 KiB
C#

using Akka.Actor;
using Akka.TestKit.Xunit2;
using NSubstitute;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
using ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Actors;
using ZB.MOM.WW.ScadaBridge.HealthMonitoring;
namespace ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests.Actors;
/// <summary>
/// WP2.1b — the DataConnectionActor against a batch-capable adapter: chunked subscribe,
/// chunked/bounded re-subscribe, the seed deadline, batched tag-resolution probes, the
/// partial-failure surface and the coalesced quality push. The existing suite covers the
/// same actor against a NON batch-capable adapter, which keeps the per-tag fallback pinned.
/// </summary>
public class DataConnectionActorBatchTests : TestKit
{
private readonly ISiteHealthCollector _health = Substitute.For<ISiteHealthCollector>();
private readonly IDataConnectionFactory _factory = Substitute.For<IDataConnectionFactory>();
private static DataConnectionOptions Options() => new()
{
ReconnectInterval = TimeSpan.FromMilliseconds(100),
TagResolutionRetryInterval = TimeSpan.FromMilliseconds(150),
TagResolutionRetryMaxInterval = TimeSpan.FromMilliseconds(600),
WriteTimeout = TimeSpan.FromSeconds(5),
SeedReadMaxAttempts = 1,
SeedReadRetryDelay = TimeSpan.FromMilliseconds(10),
SubscribeBatchSize = 5,
SubscribeBatchDelay = TimeSpan.FromMilliseconds(50),
SeedReadBatchSize = 4,
SeedReadMaxParallelism = 2,
SeedOverallTimeout = TimeSpan.FromSeconds(30),
QualityFlushInterval = TimeSpan.FromMilliseconds(200)
};
private IActorRef CreateActor(FakeBatchDataConnection adapter, DataConnectionOptions options, string name) =>
Sys.ActorOf(Props.Create(() => new DataConnectionActor(
name, adapter, options, _health, _factory, "OpcUa")), name);
private static string[] Tags(int count) => Enumerable.Range(1, count).Select(i => $"tag{i}").ToArray();
[Fact]
public void Subscribe_IssuesOneAdapterRoundTripPerChunk_NotPerTag()
{
// 12 tags at SubscribeBatchSize 5 → 3 batch calls (5/5/2) and ZERO per-tag
// subscribes. This is finding #3: the old path was one adapter call (and one OPC UA
// ApplyChanges) per tag.
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, Options(), "batch-chunking");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-chunking", Tags(12), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
var batches = adapter.SubscribeBatches.ToList();
Assert.Equal(3, batches.Count);
Assert.Equal([5, 5, 2], batches.Select(b => b.Count));
Assert.Equal(0, Volatile.Read(ref adapter.SingleSubscribeCalls));
}
[Fact]
public void Seed_UsesChunkedBulkReads_NotPerTagReads()
{
// Seeding 6 tags at SeedReadBatchSize 4 → 2 bulk reads, no single-tag reads.
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, Options(), "batch-seed");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-seed", Tags(6), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
var reads = adapter.ReadBatches.ToList();
Assert.Equal(2, reads.Count);
Assert.Equal(6, reads.Sum(r => r.Count));
Assert.Equal(0, Volatile.Read(ref adapter.SingleReadCalls));
// The seeded value still reaches the instance actor after registration.
ExpectMsg<TagValueUpdate>(u => u.Quality == QualityCode.Good, TimeSpan.FromSeconds(5));
}
[Fact]
public void Seed_HangingReads_ReturnAtTheOverallDeadline_AndTheSubscribeIsStillAcked()
{
// A device whose reads never answer must not hold SubscribeCompleted (and therefore
// the instance's ack) open: the whole seed is bounded by SeedOverallTimeout.
var options = Options();
options.SeedOverallTimeout = TimeSpan.FromMilliseconds(600);
options.SeedReadTimeout = TimeSpan.FromSeconds(30); // deliberately longer than the deadline
options.SeedReadMaxAttempts = 3;
var adapter = new FakeBatchDataConnection { HangReads = true };
var actor = CreateActor(adapter, options, "batch-seed-deadline");
var started = DateTimeOffset.UtcNow;
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-seed-deadline", Tags(3), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
var elapsed = DateTimeOffset.UtcNow - started;
// Bounded by the overall deadline, not by SeedReadTimeout (30s) or the retry budget.
Assert.True(elapsed < TimeSpan.FromSeconds(5), $"seed took {elapsed.TotalSeconds:F1}s");
// No value was seeded — the tags stay Uncertain until a change notification.
ExpectNoMsg(TimeSpan.FromMilliseconds(200));
}
[Fact]
public void PartialFailure_PerTagRow_MarksTagBad_ButTheRequestStillSucceeds()
{
// A per-tag failure row is a tag-resolution problem: Bad quality is pushed for that
// tag and the subscribe is still acked Success (the surviving tags are live).
var adapter = new FakeBatchDataConnection();
adapter.FailingTags.Add("tag2");
var actor = CreateActor(adapter, Options(), "batch-partial");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-partial", Tags(3), DateTimeOffset.UtcNow));
ExpectMsg<TagValueUpdate>(u => u.TagPath == "tag2" && u.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
}
[Fact]
public void ThrownBatch_AtConnectionLevel_FailsTheRequestAndDrivesReconnect()
{
// A THROWN batch means the whole chunk failed at connection level: the response must
// say so, and the actor must enter Reconnecting (which pushes bad quality for the
// connection).
var adapter = new FakeBatchDataConnection
{
BatchSubscribeThrows = () => new InvalidOperationException("client is not connected")
};
var actor = CreateActor(adapter, Options(), "batch-connection-fault");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-connection-fault", Tags(3), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => !m.Success && m.ErrorMessage != null, TimeSpan.FromSeconds(5));
ExpectMsg<ConnectionQualityChanged>(q => q.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
}
[Fact]
public void ResolutionProbes_AreBatched_NotOnePerTag()
{
// Every unresolved tag is probed in ONE batch call per chunk. Pre-fix the retry tick
// fired one SubscribeAsync task per unresolved tag, every tick, forever.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
foreach (var tag in Tags(6))
adapter.FailingTags.Add(tag);
var actor = CreateActor(adapter, options, "batch-probe");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-probe", Tags(6), DateTimeOffset.UtcNow));
for (var i = 0; i < 6; i++)
ExpectMsg<TagValueUpdate>(u => u.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
ExpectMsg<SubscribeTagsResponse>(TimeSpan.FromSeconds(5));
var initialCalls = adapter.SubscribeBatches.Count;
AwaitCondition(() => adapter.SubscribeBatches.Count > initialCalls, TimeSpan.FromSeconds(5));
// The probe round carried all six unresolved tags in a single call.
var probe = adapter.SubscribeBatches.Skip(initialCalls).First();
Assert.Equal(6, probe.Count);
Assert.Equal(0, Volatile.Read(ref adapter.SingleSubscribeCalls));
}
[Fact]
public void ResolutionProbes_BackOff_SoADeadDeviceIsNotProbedAtFullRate()
{
// Floor 150ms, ceiling 600ms: a fixed-interval retry would fire ~13 rounds in 2s;
// the backoff sequence (150, 300, 600, 600 …) fires far fewer.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
adapter.FailingTags.Add("tag1");
var actor = CreateActor(adapter, options, "batch-backoff");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-backoff", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<TagValueUpdate>(u => u.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
ExpectMsg<SubscribeTagsResponse>(TimeSpan.FromSeconds(5));
var initialCalls = adapter.SubscribeBatches.Count;
Thread.Sleep(2000);
var rounds = adapter.SubscribeBatches.Count - initialCalls;
Assert.InRange(rounds, 2, 8);
}
[Fact]
public void QualityCounters_ArePushedOnTransitionOnly_AndCoalesced()
{
// Repeated values at UNCHANGED quality move no counter and must produce no collector
// push at all; a genuine transition produces exactly one push per coalescing window.
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, Options(), "batch-quality");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-quality", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
AwaitCondition(() => adapter.ValueCallback != null, TimeSpan.FromSeconds(5));
// Let the seed's own transition flush, then start counting.
Thread.Sleep(400);
_health.ClearReceivedCalls();
for (var i = 0; i < 20; i++)
adapter.ValueCallback!("tag1", new TagValue(i, QualityCode.Good, DateTimeOffset.UtcNow));
Thread.Sleep(400);
Assert.DoesNotContain(_health.ReceivedCalls(), c => c.GetMethodInfo().Name == "UpdateTagQuality");
// One genuine transition → exactly one coalesced push.
adapter.ValueCallback!("tag1", new TagValue(1, QualityCode.Bad, DateTimeOffset.UtcNow));
AwaitCondition(
() => _health.ReceivedCalls().Count(c => c.GetMethodInfo().Name == "UpdateTagQuality") == 1,
TimeSpan.FromSeconds(3));
Thread.Sleep(300);
Assert.Single(_health.ReceivedCalls(), c => c.GetMethodInfo().Name == "UpdateTagQuality");
}
[Fact]
public void QualityCounters_FlushImmediatelyOnDisconnect()
{
// "Immediate bad quality on disconnect" must never wait for the coalescing timer.
var options = Options();
options.QualityFlushInterval = TimeSpan.FromSeconds(30); // would mask a deferred push
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, options, "batch-quality-disconnect");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-quality-disconnect", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
ExpectMsg<TagValueUpdate>(TimeSpan.FromSeconds(5)); // the seed
_health.ClearReceivedCalls();
adapter.RaiseDisconnected();
ExpectMsg<ConnectionQualityChanged>(q => q.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
AwaitCondition(
() => _health.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "UpdateTagQuality"),
TimeSpan.FromSeconds(3));
}
[Fact]
public void Unsubscribe_ReleasesEveryHandleInOneRoundTrip()
{
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, Options(), "batch-unsubscribe");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-unsubscribe", Tags(6), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
actor.Tell(new UnsubscribeTagsRequest("c2", "inst1", "batch-unsubscribe", DateTimeOffset.UtcNow));
AwaitCondition(() => adapter.UnsubscribeBatches.Count == 1, TimeSpan.FromSeconds(5));
Assert.True(adapter.UnsubscribeBatches.TryDequeue(out var released));
Assert.Equal(6, released!.Count);
}
[Fact]
public void Reconnect_ReSubscribesInPacedChunks_AndRestoresTheResolvedCount()
{
// The reconnect re-subscribe is chunked and paced (SubscribeBatchDelay between
// chunks) rather than firing one task per tag, and the per-tag results repopulate
// _subscriptionIds so a later unsubscribe still releases every adapter handle.
var options = Options();
options.SubscribeBatchSize = 4;
options.SubscribeBatchDelay = TimeSpan.FromMilliseconds(120);
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, options, "batch-resubscribe");
actor.Tell(new SubscribeTagsRequest("c1", "inst1", "batch-resubscribe", Tags(8), DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
var beforeReconnect = adapter.SubscribeBatches.Count;
adapter.RaiseDisconnected();
// Two re-subscribe chunks of 4.
AwaitCondition(() => adapter.SubscribeBatches.Count >= beforeReconnect + 2, TimeSpan.FromSeconds(10));
var reconnectChunks = adapter.SubscribeBatches.Skip(beforeReconnect).Take(2).ToList();
Assert.Equal([4, 4], reconnectChunks.Select(c => c.Count));
// Paced: the second chunk is not issued back-to-back with the first.
var times = adapter.SubscribeBatchTimes.Skip(beforeReconnect).Take(2).ToList();
Assert.True(times[1] - times[0] >= TimeSpan.FromMilliseconds(100),
$"chunks were {(times[1] - times[0]).TotalMilliseconds:F0}ms apart");
// Every tag is registered again, so unsubscribe releases all 8 handles.
actor.Tell(new UnsubscribeTagsRequest("c2", "inst1", "batch-resubscribe", DateTimeOffset.UtcNow));
AwaitCondition(
() => adapter.UnsubscribeBatches.Any(b => b.Count == 8),
TimeSpan.FromSeconds(10));
}
[Fact]
public void ResolutionProbe_CompletingAfterUnsubscribe_IsDiscarded_AndItsHandleIsReleased()
{
// A tag unsubscribed while its resolution probe is in flight must NOT have the
// probe's result applied: HandleUnsubscribe already dropped it from
// _unresolvedTags and from TotalSubscribedTags, so storing the handle would push
// ResolvedTags above TotalSubscribedTags forever (and drive TotalSubscribedTags
// negative on the next redeploy) while leaking the adapter monitored item, which
// no later unsubscribe could ever reference.
var options = Options();
options.SubscribeBatchSize = 10;
// Long enough that the probe cannot fire before the gate below is armed.
options.TagResolutionRetryInterval = TimeSpan.FromMilliseconds(800);
options.TagResolutionRetryMaxInterval = TimeSpan.FromSeconds(2);
var adapter = new FakeBatchDataConnection();
adapter.FailingTags.Add("tag1");
var actor = CreateActor(adapter, options, "batch-probe-unsubscribe-race");
actor.Tell(new SubscribeTagsRequest(
"c1", "inst1", "batch-probe-unsubscribe-race", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<TagValueUpdate>(u => u.Quality == QualityCode.Bad, TimeSpan.FromSeconds(5));
ExpectMsg<SubscribeTagsResponse>(TimeSpan.FromSeconds(5));
var afterSubscribe = Health(actor);
Assert.Equal(1, afterSubscribe.TotalSubscribedTags);
Assert.Equal(0, afterSubscribe.ResolvedTags);
// Park the next probe inside the adapter, and let it succeed when released.
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
adapter.SubscribeGate = gate.Task;
adapter.FailingTags.Clear();
var beforeProbe = adapter.SubscribeBatches.Count;
AwaitCondition(() => adapter.SubscribeBatches.Count > beforeProbe, TimeSpan.FromSeconds(10));
// Unsubscribe while the probe is still in flight, and confirm it has been applied
// before the probe result lands (same-sender ordering makes the report a barrier).
actor.Tell(new UnsubscribeTagsRequest("c2", "inst1", "batch-probe-unsubscribe-race", DateTimeOffset.UtcNow));
var afterUnsubscribe = Health(actor);
Assert.Equal(0, afterUnsubscribe.TotalSubscribedTags);
Assert.Equal(0, afterUnsubscribe.ResolvedTags);
// The tag was still unresolved, so the unsubscribe itself had no handle to
// release — every id released from here on is the raced probe's. (This also
// rules out a vacuous run in which the probe resolved before the gate was armed.)
Assert.Empty(adapter.UnsubscribeBatches);
gate.SetResult();
// The orphaned handle is released back to the adapter…
AwaitCondition(
() => adapter.UnsubscribeBatches.Any(b => b.Count == 1),
TimeSpan.FromSeconds(10));
// …and the counters are untouched by the discarded result.
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(0, report.TotalSubscribedTags);
Assert.Equal(0, report.ResolvedTags);
}, TimeSpan.FromSeconds(5));
// A redeploy round trip still books exactly one tag in and one tag out — pre-fix
// the stale handle made this read Total=0/Resolved=1 and then Total=-1.
adapter.SubscribeGate = null;
actor.Tell(new SubscribeTagsRequest(
"c3", "inst1", "batch-probe-unsubscribe-race", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
var afterRedeploy = Health(actor);
Assert.Equal(1, afterRedeploy.TotalSubscribedTags);
Assert.Equal(1, afterRedeploy.ResolvedTags);
actor.Tell(new UnsubscribeTagsRequest("c4", "inst1", "batch-probe-unsubscribe-race", DateTimeOffset.UtcNow));
var afterFinalUnsubscribe = Health(actor);
Assert.Equal(0, afterFinalUnsubscribe.TotalSubscribedTags);
Assert.Equal(0, afterFinalUnsubscribe.ResolvedTags);
}
[Fact]
public void ReconnectResubscribe_CompletingAfterUnsubscribe_IsDiscarded_AndItsHandleIsReleased()
{
// Same race on the OTHER batch source: the reconnect re-subscribe. ReSubscribeAll
// has already zeroed ResolvedTags, so applying the late result would report a
// resolved tag for an instance that no longer exists and leak its handle.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, options, "batch-resubscribe-unsubscribe-race");
actor.Tell(new SubscribeTagsRequest(
"c1", "inst1", "batch-resubscribe-unsubscribe-race", ["tag1"], DateTimeOffset.UtcNow));
ExpectMsg<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(5));
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
adapter.SubscribeGate = gate.Task;
var beforeReconnect = adapter.SubscribeBatches.Count;
adapter.RaiseDisconnected();
AwaitCondition(() => adapter.SubscribeBatches.Count > beforeReconnect, TimeSpan.FromSeconds(10));
actor.Tell(new UnsubscribeTagsRequest(
"c2", "inst1", "batch-resubscribe-unsubscribe-race", DateTimeOffset.UtcNow));
// The unsubscribe found no handle to release (ReSubscribeAll cleared
// _subscriptionIds), so no release round trip has happened yet.
Health(actor);
Assert.Empty(adapter.UnsubscribeBatches);
gate.SetResult();
// The handle minted by the re-subscribe is released rather than leaked, and the
// discarded row books no resolved tag. (TotalSubscribedTags across a reconnect
// window is a separate, pre-existing accounting gap — ReSubscribeAll clears the
// maps HandleUnsubscribe decrements from — so this pins the invariant that
// matters here: ResolvedTags never exceeds it.)
AwaitCondition(
() => adapter.UnsubscribeBatches.Any(b => b.Count == 1),
TimeSpan.FromSeconds(10));
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(0, report.ResolvedTags);
Assert.True(report.ResolvedTags <= report.TotalSubscribedTags);
}, TimeSpan.FromSeconds(5));
}
// ── Tag-resolution health counts: derived from the per-tag counted set ──
//
// Arch-review remediation residual #1. TotalSubscribedTags / ResolvedTags used to be
// two int fields incremented and decremented at five independent sites. The reconnect
// path cleared the very maps those decrements keyed off (_subscriptionIds and
// _unresolvedTags), so an unsubscribe landing inside a reconnect window matched NEITHER
// decrement branch and leaked a phantom tag into the total — permanently, and cumulative
// under churn. They are now derived at report time from _instancesByTag (the per-tag
// counted set) and _subscriptionIds, which makes that class of drift unrepresentable.
[Fact]
public void TagResolutionCounts_UnsubscribeInsideAReconnectWindow_DoesNotLeakASubscribedTag()
{
// THE residual repro. Each cycle: subscribe → drop the connection → hold the
// reconnect re-subscribe in flight → unsubscribe inside that window → let the batch
// land. Pre-fix the total read 1 after the first cycle's unsubscribe (nothing
// decremented it) and then 2, 3 … at the head of each following cycle — a +1 leak
// per churn round that never recovers. Post-fix every cycle books exactly one tag
// in and one tag out.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, options, "counts-reconnect-churn");
for (var cycle = 1; cycle <= 3; cycle++)
{
actor.Tell(new SubscribeTagsRequest(
$"s{cycle}", "inst1", "counts-reconnect-churn", ["tag1"], DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
var afterSubscribe = Health(actor);
Assert.Equal(1, afterSubscribe.TotalSubscribedTags);
Assert.Equal(1, afterSubscribe.ResolvedTags);
// Park the reconnect re-subscribe: ReSubscribeAll has already cleared
// _subscriptionIds and _unresolvedTags, and the batch has not come back yet.
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
adapter.SubscribeGate = gate.Task;
var beforeReconnect = adapter.SubscribeBatches.Count;
adapter.RaiseDisconnected();
AwaitCondition(() => adapter.SubscribeBatches.Count > beforeReconnect, TimeSpan.FromSeconds(10));
// Unsubscribe INSIDE the reconnect window (same-sender ordering makes the
// health report a barrier proving it was applied first).
actor.Tell(new UnsubscribeTagsRequest(
$"u{cycle}", "inst1", "counts-reconnect-churn", DateTimeOffset.UtcNow));
var afterUnsubscribe = Health(actor);
Assert.Equal(0, afterUnsubscribe.TotalSubscribedTags);
Assert.Equal(0, afterUnsubscribe.ResolvedTags);
// Release the raced batch. Its rows are discarded and its handle released —
// one release per cycle, which is also the barrier that the discard ran.
gate.SetResult();
adapter.SubscribeGate = null;
AwaitCondition(() => adapter.UnsubscribeBatches.Count >= cycle, TimeSpan.FromSeconds(10));
var afterDiscard = Health(actor);
Assert.Equal(0, afterDiscard.TotalSubscribedTags);
Assert.Equal(0, afterDiscard.ResolvedTags);
}
}
[Fact]
public void TagResolutionCounts_SharedTagUnsubscribedInsideAReconnectWindow_StillCountsForTheOtherInstance()
{
// The counted-set semantics, not a bare reference count: one instance leaving during
// a reconnect window must leave the tag counted (the other instance still subscribes)
// and must not release its handle.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
var actor = CreateActor(adapter, options, "counts-shared-reconnect");
actor.Tell(new SubscribeTagsRequest("s1", "instA", "counts-shared-reconnect", ["tag1"], DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
actor.Tell(new SubscribeTagsRequest("s2", "instB", "counts-shared-reconnect", ["tag1"], DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
var shared = Health(actor);
Assert.Equal(1, shared.TotalSubscribedTags);
Assert.Equal(1, shared.ResolvedTags);
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
adapter.SubscribeGate = gate.Task;
var beforeReconnect = adapter.SubscribeBatches.Count;
adapter.RaiseDisconnected();
AwaitCondition(() => adapter.SubscribeBatches.Count > beforeReconnect, TimeSpan.FromSeconds(10));
actor.Tell(new UnsubscribeTagsRequest("u1", "instA", "counts-shared-reconnect", DateTimeOffset.UtcNow));
var afterOneLeft = Health(actor);
Assert.Equal(1, afterOneLeft.TotalSubscribedTags);
Assert.Equal(0, afterOneLeft.ResolvedTags); // ReSubscribeAll cleared the handles
// instB still wants the tag, so the raced batch row is APPLIED (not discarded) and
// nothing is released back to the adapter.
gate.SetResult();
adapter.SubscribeGate = null;
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(1, report.TotalSubscribedTags);
Assert.Equal(1, report.ResolvedTags);
}, TimeSpan.FromSeconds(10));
Assert.Empty(adapter.UnsubscribeBatches);
// The last subscriber leaving drops the tag from both counts and releases it.
actor.Tell(new UnsubscribeTagsRequest("u2", "instB", "counts-shared-reconnect", DateTimeOffset.UtcNow));
var afterBothLeft = Health(actor);
Assert.Equal(0, afterBothLeft.TotalSubscribedTags);
Assert.Equal(0, afterBothLeft.ResolvedTags);
AwaitCondition(() => adapter.UnsubscribeBatches.Any(b => b.Count == 1), TimeSpan.FromSeconds(10));
}
[Fact]
public void TagResolutionCounts_ConnectionLevelFailureThenRecovery_KeepResolvedWithinTheTotal()
{
// A tag whose FIRST subscribe fails at connection level is subscribed by an instance
// (it is re-issued from _subscriptionsByInstance on reconnect) but is neither
// resolved nor unresolved. The retired scalar counted it in neither, so once the
// reconnect re-subscribe resolved it the report read ResolvedTags=1 against
// TotalSubscribedTags=0 — resolved above total, and a total driven negative by the
// eventual unsubscribe.
var options = Options();
options.SubscribeBatchSize = 10;
var calls = 0;
var adapter = new FakeBatchDataConnection
{
// Fail the initial subscribe at connection level; let the reconnect through.
BatchSubscribeThrows = () => Interlocked.Increment(ref calls) == 1
? new InvalidOperationException("client is not connected")
: null
};
var actor = CreateActor(adapter, options, "counts-connection-level");
actor.Tell(new SubscribeTagsRequest(
"s1", "inst1", "counts-connection-level", ["tag1"], DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => !m.Success, TimeSpan.FromSeconds(10));
// The tag is subscribed by the instance from the moment it is registered, whatever
// the adapter said — so it counts toward the total and not toward resolved.
var afterFault = Health(actor);
Assert.Equal(1, afterFault.TotalSubscribedTags);
Assert.Equal(0, afterFault.ResolvedTags);
// The reconnect re-subscribe resolves it: 1/1, never 1/0-then-resolved-above-total.
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(1, report.TotalSubscribedTags);
Assert.Equal(1, report.ResolvedTags);
}, TimeSpan.FromSeconds(15));
actor.Tell(new UnsubscribeTagsRequest("u1", "inst1", "counts-connection-level", DateTimeOffset.UtcNow));
var afterUnsubscribe = Health(actor);
Assert.Equal(0, afterUnsubscribe.TotalSubscribedTags);
Assert.Equal(0, afterUnsubscribe.ResolvedTags);
}
[Fact]
public void TagResolutionCounts_SurvivePlainSubscribeUnsubscribeCycles()
{
// The undramatic path, pinned so the derived counts cannot regress on it: repeated
// deploy/undeploy round trips with a mix of resolved and unresolved tags always read
// back the same numbers, with no accumulation across cycles.
var options = Options();
options.SubscribeBatchSize = 10;
// Long enough that a resolution probe cannot resolve tag4 mid-assertion.
options.TagResolutionRetryInterval = TimeSpan.FromSeconds(30);
options.TagResolutionRetryMaxInterval = TimeSpan.FromSeconds(60);
var adapter = new FakeBatchDataConnection();
adapter.FailingTags.Add("tag4");
var actor = CreateActor(adapter, options, "counts-plain-cycles");
for (var cycle = 1; cycle <= 3; cycle++)
{
actor.Tell(new SubscribeTagsRequest(
$"s{cycle}", "inst1", "counts-plain-cycles", Tags(4), DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
var afterSubscribe = Health(actor);
Assert.Equal(4, afterSubscribe.TotalSubscribedTags); // 3 resolved + 1 unresolved
Assert.Equal(3, afterSubscribe.ResolvedTags);
actor.Tell(new UnsubscribeTagsRequest(
$"u{cycle}", "inst1", "counts-plain-cycles", DateTimeOffset.UtcNow));
var afterUnsubscribe = Health(actor);
Assert.Equal(0, afterUnsubscribe.TotalSubscribedTags);
Assert.Equal(0, afterUnsubscribe.ResolvedTags);
}
}
[Fact]
public void TagResolutionCounts_AreCarriedThroughACompletedReconnectReSubscribe()
{
// A completed reconnect re-subscribe restores the resolved count and leaves the
// total exactly where it was — the tags never stopped being subscribed.
var options = Options();
options.SubscribeBatchSize = 10;
var adapter = new FakeBatchDataConnection();
adapter.FailingTags.Add("tag5");
var actor = CreateActor(adapter, options, "counts-reconnect-restore");
actor.Tell(new SubscribeTagsRequest(
"s1", "inst1", "counts-reconnect-restore", Tags(5), DateTimeOffset.UtcNow));
FishForMessage<SubscribeTagsResponse>(m => m.Success, TimeSpan.FromSeconds(10));
var beforeReconnect = Health(actor);
Assert.Equal(5, beforeReconnect.TotalSubscribedTags);
Assert.Equal(4, beforeReconnect.ResolvedTags);
adapter.RaiseDisconnected();
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(5, report.TotalSubscribedTags);
Assert.Equal(4, report.ResolvedTags);
}, TimeSpan.FromSeconds(15));
// The still-unresolved tag resolving on a later probe moves ONLY the resolved count.
adapter.FailingTags.Clear();
AwaitAssert(() =>
{
var report = Health(actor);
Assert.Equal(5, report.TotalSubscribedTags);
Assert.Equal(5, report.ResolvedTags);
}, TimeSpan.FromSeconds(15));
}
/// <summary>Point-in-time counters straight off the actor, fished past any pending pushes.</summary>
private DataConnectionHealthReport Health(IActorRef actor)
{
actor.Tell(new DataConnectionActor.GetHealthReport());
return FishForMessage<DataConnectionHealthReport>(_ => true, TimeSpan.FromSeconds(5));
}
}