Nothing counted open import sessions and nothing logged a rejection at
MaxConcurrentImportSessions (default 8), so the register-row-43 session leak
could only be inferred from rotating test failures.
- Gauge scadabridge.central.transport.import_sessions.open on the existing
ZB.MOM.WW.ScadaBridge meter — already in SiteServiceRegistration.ObservedMeters
(the ZbTelemetryOptions.Meters allowlist), so no telemetry config change is
needed and the series is not silently dropped. Provider-backed, mirroring the
StoreAndForward queue-depth gauge: registered by BundleSessionEvictionService
.StartAsync (Transport's only lifecycle seam) and identity-checked-cleared on
StopAsync so a late stop cannot clobber a newer registrant.
- IBundleSessionStore.OpenSessionCount counts only UNEXPIRED sessions. The raw
dictionary count would report the node as pinned at the cap for up to a
one-minute sweep interval after a burst had drained — the exact false positive
the instrument exists to rule out.
- BundleSessionStore.Open logs Warning with open count, cap and TTL when it
rejects. Fires only on a real cap hit: a store full of expired sessions is
reclaimed first and logs nothing.
- Docs: docs/components/Transport.md + docs/requirements/Component-Transport.md.
Tests: Transport 173 passed (+6 new — Warning content, two negative controls,
unexpired-only counting, gauge register/clear, no-clobber-on-late-stop).
Joseph Doherty
372ea4df1b