Comment/XML-doc changes only, no code logic:
- strip project-tracking references (WP*, P*-*, row-NN, #NN, Task N) from
comments, keeping the explanatory rationale
- add missing summaries, <param>, <returns>, <typeparam> and <inheritdoc/>
- replace misused <inheritdoc/> with real docs; where <inheritdoc/> was
combined with useful remarks, move the rationale into // comments
- drop stale replicationActor <param> on DeploymentManagerActor ctor
Remaining 5 are false positives (CWE-1236 x2, failures-1, year-0001, M365).
Build 0 errors / 0 warnings.
P3-4 — SiteAlarmAggregatorActor pinned _openInFlight forever on a stream open
that produced none of its three peer-driven outcomes. SiteStreamGrpcClient gives
up on response headers after ConnectedHeaderTimeout (10s) and then treats the
first received EVENT as its fallback connected signal, so an alarm-only site
that stays quiet supplies neither — leaving _streamDown=true AND _openInFlight=
true, which makes OnReconcileTick's reopen guard (_streamDown && !_openInFlight)
skip every tick until the site's 4h max stream lifetime ends the call.
Fix: bound one open attempt with a generation-fenced single-shot deadline
(GrpcAlarmStreamOpenTimedOut, ctor-injected, production default 30s — above the
10s header timeout, below the 60s reconcile interval). Firing it releases the
flag and nothing else: no retry-budget spend, no node flip, no liveness
republish, and the abandoned subscription is left running so a merely-slow
connect still comes up normally. Self-healing rather than reachability analysis.
The deadline is cancelled on connect / error / graceful completion.
P3-5 — SiteStreamGrpcServer cancelled the incumbent stream on a duplicate
correlation id and only THEN checked the concurrency cap. Checking Count >= max
after the removal is right at exactly the cap but wrong above it, and above it
is reachable because the cap check is documented check-then-act: two subscribes
that both clear it before either registers overshoot by one. In that window a
routine reconnect killed a healthy stream AND was refused with
ResourceExhausted, leaving the correlation with ZERO streams until its next
retry.
Fix: claim the removal, consult the cap only for a genuinely NEW correlation id,
then cancel. A replacement is net-neutral on the count so it never consults the
cap; a refused new subscriber cancelled nothing (TryRemove found nothing), so
the incumbent survives. Newest-wins is unchanged — a fresh authenticated
subscribe still displaces a dead/wedged incumbent.
Tests (both shown failing against the unfixed code):
- OpenAttemptThatNeverResolves_ReleasesTheInFlightGuard_SoTheTickCanReopen —
fails (reopen never happens) with the deadline arming disabled.
- OpenDeadline_DoesNotFire_OnAStreamThatConnects_NorFlipNodeOrBurnBudget —
inertness lock on every healthy path.
- AtCapOvershoot_DuplicateReconnect_IsNotRefused_AndLeavesExactlyOneLiveStream —
fails with ResourceExhausted against the old ordering; the overshoot is driven
deterministically by parking both openers on the ServerCallContext token read,
which sits between the cap check and the _activeStreams insert.
- AtCap_AGenuinelyNewSubscriber_IsStillRefused_AndTheIncumbentSurvives.
The P3-4 test's doc comment carries the honesty note: the aggregator-side
starvation reproduces exactly, but how often the >10s header delay that gets you
there occurs in production is NOT demonstrated — the site flushes headers
explicitly as soon as its relay is attached, so the budget has to be consumed by
connect + handshake + server scheduling instead.
Extend CommunicationOptionsValidator with eager bounds for the four T4
live-alarm-cache options (linger >= 0, reconcile > 0, seed concurrency 1..64,
subscribers-per-site >= 1). Enforce the per-site viewer cap fail-safe in
SiteAlarmLiveCacheService.Subscribe (reject excess viewers with a no-op
disposable rather than growing the list or throwing into the Blazor render
path). Surface two telemetry instruments on the existing ScadaBridgeTelemetry
meter: an active-aggregator observable gauge and a reconnect counter, wired from
the aggregator actor's PreStart/PostStop and its NodeA<->NodeB flip /
reconcile-driven reopen.
Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj
Adds the active-central-node, in-memory, reference-counted per-site live alarm
cache backing the operator Alarm Summary page. No persisted central alarm store
([PERM]) — no EF entity/table/migration/DbSet.
- ISiteAlarmLiveCache (new): singleton seam — Subscribe(siteId, onChanged) ->
IDisposable (ref-counted, linger stop on last-out), GetCurrentAlarms, IsLive.
- SiteAlarmAggregatorActor (new): one per site. Seed-then-stream ordering copied
from DebugStreamBridgeActor — open the site-wide alarm-only gRPC stream first,
buffer live deltas while the snapshot fan-out runs, flush with per-key dedup
(AlarmKey = InstanceUniqueName|AlarmName|SourceReference), then live pass-through
into an in-memory dict. Placeholder rows seeded from the snapshot and never
expected on the stream; a real-alarm delta (distinct key) never wipes them.
NodeA<->NodeB reconnect (retry budget + stability window), reconnect re-seeds,
periodic reconcile (authoritative clear-and-rebuild) corrects instance-set drift,
and a budget-exhausted stream self-heals on the next reconcile tick.
- SiteAlarmLiveCacheService (new): DI singleton facade — viewer reference-counting,
linger-delayed last-out stop (version + TryRemove(ref) race guards), the
snapshot fan-out seed (RequestDebugSnapshotAsync per Enabled instance, capped),
bounded start-retry self-heal on transient start failure, and the immutable
published-snapshot store the page reads. Cache mutated only on the actor thread;
viewer callbacks invoked outside the lock.
- CommunicationOptions: LiveAlarmCacheLinger (30s), LiveAlarmCacheReconcileInterval
(60s), LiveAlarmCacheSeedConcurrency (8), LiveAlarmCacheMaxSubscribersPerSite
(200). Task 6 formalizes eager validation + telemetry.
- DI registration + AkkaHostedService SetActorSystem wiring on the active central node.
- Tests: 14 actor (seed/stream ordering, dedup, native-alarm parity, placeholder
coherence, reconnect re-seed, reconcile replace, self-heal, stop) + 6 service
(shared start, linger stop, resubscribe cancels stop, idempotent dispose, unknown
site, transient-start self-heal). Code-reviewer pass: no persistence, no Critical;
both Important findings addressed.
Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj
Joseph Doherty