A graceful stop of a site node whose peer holds an open LocalDb sync stream
left the Akka cluster ~30 s late (the ScadaBridge half of lmxopcua#906,
scadaproj#57). WebApplication stops the web server before AkkaHostedService,
whose StopAsync ran CoordinatedShutdown, and Kestrel's graceful drain waited
the whole ShutdownTimeout for /localdb_sync.v1.LocalDbSync/Sync: LocalDb 0.3.7
observes only the call token, which Kestrel cancels at the END of the drain.
CancelAllStreams only covered SiteStreamGrpcServer's own streams.
- AkkaHostedService is now an IHostedLifecycleService. StoppingAsync runs
before any hosted service's StopAsync (Kestrel's included): marks the stop
intentional, raises ApplicationStopping (so CancelAllStreams still precedes
actor teardown), then runs and awaits CoordinatedShutdown(ClrExitReason),
bounded by the host shutdown token. StopAsync returns the same completed
shutdown. Exit codes unchanged: planned stop exits 0; only a termination
outside host shutdown (self-down / #132 shut-out) exits 75. No Akka.Hosting
here, so no ClusterLeavingReason/-1 exit-code path is involved.
- ShutdownStreamCancellationInterceptor, innermost on both the central and the
site AddGrpc pipelines: every streaming call's token is linked with
ApplicationStopping; new streams are refused Unavailable while stopping.
Covers the LocalDb sync stream until LocalDb 0.3.8 is pinned.
Evidence (IntegrationTests/GracefulStopWithOpenSyncStreamTests: real
WebApplication + Kestrel h2c + MapZbLocalDbSync behind LocalDbSyncAuthInterceptor
+ a real LocalDb SyncBackgroundService peer + the production AkkaHostedService
forming a single-member cluster, 8 s drain budget, IServer wrapped to timestamp
the drain): before 8859 ms stop, member removed at 8834 ms, drain began at 0 ms;
after 960 ms stop, member removed at 950 ms, drain began at 959 ms.
Mutations (all killed): StoppingAsync skips CoordinatedShutdown; interceptor
passes the original context (stop 8003 ms); no Unavailable refusal; StoppingAsync
does not raise ApplicationStopping; lifecycle interface dropped; site pipeline
loses the interceptor.
Release build of the solution: 0 warnings. Host.Tests 733/733,
IntegrationTests 133/133, Communication.Tests 843/843.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Joseph Doherty
1a6108c402