fix(sessions): expose DetachGraceSeconds in effective-config; single clock; close reconnect-vs-sweep race

- EffectiveSessionConfiguration: add DetachGraceSeconds field; GatewayConfigurationProvider
  forwards value.Sessions.DetachGraceSeconds (blocker fix).
- GatewaySession.InvokeAsync and ReadEventsAsync: switch TouchClientActivity calls from
  DateTimeOffset.UtcNow to _eventStreaming.TimeProvider.GetUtcNow() so Task 12 fake-clock
  control works end-to-end (split-clock fix).
- TOCTOU fix: add TryBeginCloseIfExpired(now, out alreadyClosing) to GatewaySession that
  re-checks IsLeaseExpiredCore/IsDetachGraceExpiredCore AND _activeEventSubscriberCount==0
  under _syncRoot before transitioning to Closing; CloseExpiredLeasesAsync calls it before
  CloseSessionCoreAsync so a reattach that wins the race leaves the session Ready/usable.
- Minors: lease-expiry-takes-precedence comment in CloseExpiredLeasesAsync; TOCTOU comment
  block; sweep-cycle latency note added to SessionOptions.DetachGraceSeconds XML doc and to
  GatewayConfiguration.md DetachGraceSeconds row.
- New tests: TryBeginCloseIfExpired_ReattachedSubscriberWinsRace_DeclinesClose (GatewaySession),
  CloseExpiredLeasesAsync_DoesNotCloseSessionThatReattachedBeforeSweepCloses (SessionManager),
  plus IsLeaseExpiredCore/IsDetachGraceExpiredCore private helpers used by the guard.

This commit is contained in:

Joseph Doherty

2026-06-16 07:11:59 -04:00

parent db95f8644f

commit 042f5e3d82

8 changed files with 173 additions and 3 deletions

									
										src/ZB.MOM.WW.MxGateway.Server/Configuration/EffectiveSessionConfiguration.cs
									
		+1
		
												View File
												
				@@ -6,5 +6,6 @@ public sealed record EffectiveSessionConfiguration(

				    int MaxPendingCommandsPerSession,

				    int DefaultLeaseSeconds,

				    int LeaseSweepIntervalSeconds,

				    int DetachGraceSeconds,

				    bool AllowMultipleEventSubscribers,

				    int MaxEventSubscribersPerSession);