shankar0123 3e5cc86c5a fix(reliability): TICKET-002 add scheduler idempotency guards and graceful shutdown ...

## Summary

Fixes two critical scheduler reliability issues in certctl:

### TICKET-002 (CRITICAL): Scheduler job idempotency
- Added atomic.Bool guards to all 6 scheduler loops (renewal, job processor, agent health, notifications, short-lived expiry, network scan)
- Uses CompareAndSwap pattern to prevent duplicate execution if previous job is still running
- Logs warning when a tick is skipped due to in-flight work
- Prevents runaway scheduler duplicates and resource exhaustion

### TICKET-011 (MEDIUM): Graceful shutdown
- Added sync.WaitGroup to track in-flight scheduler work
- Each job is wrapped in wg.Add(1)/wg.Done() for lifecycle tracking
- New WaitForCompletion(timeout) method waits for all in-flight work to complete
- Integrates into main.go: after context cancellation, waits up to 30s for jobs to finish before closing DB
- Graceful shutdown ensures no work is lost during server restart/termination

## Changes

**internal/scheduler/scheduler.go:**
- Imports: added "errors", "sync", "sync/atomic"
- Scheduler struct: added 6 atomic.Bool fields (one per loop) + sync.WaitGroup
- All 6 loop functions: spawn goroutines with wg.Add/Done, check atomic guard on each tick, skip tick if already running
- New WaitForCompletion(timeout) method with timeout support
- New ErrSchedulerShutdownTimeout error type

**cmd/server/main.go:**
- After context cancellation and before HTTP shutdown, call sched.WaitForCompletion(30 * time.Second)
- Logs "waiting for scheduler to complete in-flight work" and any errors

**internal/scheduler/scheduler_test.go (new file):**
- Mock services for testing (renewal, job, agent, notification, network scan)
- TestSchedulerIdempotencyGuard: verifies slow job doesn't cause duplicate execution
- TestWaitForCompletionSuccess: verifies graceful shutdown with adequate timeout
- TestWaitForCompletionTimeout: verifies timeout is respected
- TestSchedulerMultipleLoopsIdempotency: verifies all 6 loops respect idempotency
- TestSchedulerGracefulShutdown: end-to-end graceful shutdown flow

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

2026-03-27 21:34:07 -04:00

..

scheduler_test.go

fix(reliability): TICKET-002 add scheduler idempotency guards and graceful shutdown

2026-03-27 21:34:07 -04:00

scheduler.go

fix(security): TICKET-009 add HTTP timeouts to notifier clients

2026-03-27 21:33:31 -04:00