Closes the HostedService half of Phase 6.1 Stream E.2 flagged as a follow-up
when the DriverResilienceStatusTracker shipped in PR #82. The Admin /hosts
column refresh + SignalR push + red-badge visual (Stream E.3) remain
deferred to the visual-compliance pass — this PR owns the persistence
story alone.
Server.Hosting:
- ResilienceStatusPublisherHostedService : BackgroundService. Samples the
DriverResilienceStatusTracker every TickInterval (default 5 s) and upserts
each (DriverInstanceId, HostName) counter pair into
DriverInstanceResilienceStatus via EF. New rows on first sight; in-place
updates on subsequent ticks.
- PersistOnceAsync extracted public so tests drive one tick directly —
matches the ScheduledRecycleHostedService pattern for deterministic
timing.
- Best-effort persistence: a DB outage logs a warning + continues; the next
tick retries. Never crashes the app on sample failure. Cancellation
propagates through cleanly.
- Tracks the bulkhead depth / recycle / footprint columns the entity was
designed for. CurrentBulkheadDepth currently persisted as 0 — the tracker
doesn't yet expose live bulkhead depth; a narrower follow-up wires the
Polly bulkhead-depth observer into the tracker.
Tests (6 new in ResilienceStatusPublisherHostedServiceTests):
- Empty tracker → tick is a no-op, zero rows written.
- Single-host counters → upsert a new row with ConsecutiveFailures + breaker
timestamp + sampled timestamp.
- Second tick updates the existing row in place (not a second insert).
- Multi-host pairs persist independently.
- Footprint counters (Baseline + Current) round-trip.
- TickCount advances on every PersistOnceAsync call.
Full solution dotnet test: 1225 passing (was 1219, +6). Pre-existing
Client.CLI Subscribe flake unchanged.
Production wiring (Program.cs) example:
builder.Services.AddSingleton<DriverResilienceStatusTracker>();
builder.Services.AddHostedService<ResilienceStatusPublisherHostedService>();
// Tracker gets wired into CapabilityInvoker via OtOpcUaServer resolution
// + the existing Phase 6.1 layer.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
