Critical alerts can no longer be silently dropped by a transient
notifier failure. Failed notification attempts now ride an exponential
backoff retry loop, with a 5-attempt budget before promotion to the
dead-letter queue for operator intervention.
Schema (migration 000016, idempotent):
- retry_count INTEGER NOT NULL DEFAULT 0
- next_retry_at TIMESTAMPTZ
- last_error TEXT
- idx_notification_events_retry_sweep partial index
(next_retry_at) WHERE status='failed' AND next_retry_at IS NOT NULL
Dead rows clear next_retry_at so the index stops matching them.
Service contract:
- NotificationService.RetryFailedNotifications drives 2^n-minute
exponential backoff capped at 1h (notifRetryBackoffCap) with
5-attempt budget (notifRetryMaxAttempts).
- Exhaustion (RetryCount >= notifRetryMaxAttempts-1) promotes to
status='dead' via MarkAsDead.
- Non-terminal failures record via RecordFailedAttempt.
- Success path promotes to 'sent' without touching retry_count
(audit preserves "delivered on attempt N").
- Missing-notifier branch defensively promotes to 'sent' to avoid
wedging a row on a deleted channel.
- RequeueNotification operator escape hatch atomically resets
retry_count -> 0, next_retry_at -> NULL, last_error -> NULL,
status -> pending via notifRepo.Requeue.
Scheduler:
- New always-on notificationRetryLoop wired into the base loop set at
CERTCTL_NOTIFICATION_RETRY_INTERVAL (default 2m).
- sync/atomic.Bool idempotency guard.
- sync.WaitGroup shutdown drain via WaitForCompletion.
StatsService:
- SetNotifRepo setter pattern preserves 9 pre-existing
NewStatsService call sites (main.go + stats_test.go + 8 digest
tests) without touching the constructor signature.
- DashboardSummary.NotificationsDead populated via
notifRepo.CountByStatus(ctx, "dead") — nil-safe when unwired
(reports zero on systems without a notification repository).
- CountByStatus error is non-fatal (dashboard summary is
best-effort for this field).
- Prometheus certctl_notification_dead_total counter emitted from
the same snapshot.
Handler:
- New POST /api/v1/notifications/{id}/requeue endpoint.
- dead status surfaces to MCP + CLI.
Frontend:
- NotificationsPage gains two-tab toolbar ("All" / "Dead letter")
with queryKey: ['notifications', activeTab] so switching tabs
doesn't serve stale data until the 30s refetch.
- Dead rows surface "Retry {n}/5" + truncated last_error with
full-text title tooltip.
- Requeue mutation wrapped as
mutationFn: (id: string) => requeueNotification(id)
to prevent react-query v5's positional context argument from
leaking into the API client — pinned against future refactors
by strict-match toHaveBeenCalledWith('notif-dead-001') in
NotificationsPage.test.tsx:181.
Closes I-005.
M21 adds server-side active TLS scanning of CIDR ranges with concurrent
probing, sentinel agent pattern for pipeline reuse, and full CRUD API for
scan targets. M22 adds Prometheus exposition format endpoint alongside
existing JSON metrics. Comprehensive documentation audit updates all docs
to reflect 91 endpoints, 19 tables, 6 scheduler loops, and 900+ tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
shankar0123