---
phase: 02-backend-services
plan: 04
subsystem: infra
tags: [firebase-functions, cloud-scheduler, health-probes, retention-cleanup, onSchedule]

# Dependency graph
requires:
  - phase: 02-backend-services
    provides: healthProbeService.runAllProbes(), alertService.evaluateAndAlert(), HealthCheckModel.deleteOlderThan(), AlertEventModel.deleteOlderThan(), deleteProcessingEventsOlderThan()
provides:
  - runHealthProbes Cloud Function export (every 5 minutes, separate from processDocumentJobs)
  - runRetentionCleanup Cloud Function export (weekly Monday 02:00, 30-day rolling deletion)
affects: [03-api-layer, 04-frontend, phase-03, phase-04]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "onSchedule Cloud Functions use dynamic import() to avoid cold-start overhead and module-level secret access"
    - "Health probes as separate named Cloud Function — never piggybacked on processDocumentJobs (PITFALL-2)"
    - "retryCount: 0 for health probes — 5-minute schedule makes retries unnecessary"
    - "Promise.all() for parallel multi-table retention cleanup"

key-files:
  created: []
  modified:
    - backend/src/index.ts

key-decisions:
  - "runHealthProbes is completely separate from processDocumentJobs — distinct Cloud Function, distinct schedule (PITFALL-2 compliance)"
  - "retryCount: 0 on runHealthProbes — probes recur every 5 minutes, retry would create confusing duplicate results"
  - "runRetentionCleanup uses Promise.all() for parallel deletes — three tables are independent, no ordering constraint"
  - "runRetentionCleanup only deletes monitoring tables (service_health_checks, alert_events, document_processing_events) — agentic RAG tables out of scope per research Open Question 4"
  - "RETENTION_DAYS = 30 is a constant, not configurable — matches INFR-03 spec exactly"

patterns-established:
  - "Scheduled Cloud Functions: dynamic import() + explicit secrets array per function"
  - "Retention cleanup: Promise.all([model.deleteOlderThan(), ...]) pattern for parallel table cleanup"

requirements-completed: [HLTH-03, INFR-03]

# Metrics
duration: 1min
completed: 2026-02-24
---

# Phase 2 Plan 04: Scheduled Cloud Function Exports Summary

**Two new Firebase onSchedule Cloud Functions: runHealthProbes (5-minute interval) and runRetentionCleanup (weekly Monday 02:00) added to index.ts as standalone exports decoupled from document processing**

## Performance

- **Duration:** ~1 min
- **Started:** 2026-02-24T19:34:20Z
- **Completed:** 2026-02-24T19:35:17Z
- **Tasks:** 2
- **Files modified:** 1

## Accomplishments
- Added `runHealthProbes` onSchedule export that calls `healthProbeService.runAllProbes()` then `alertService.evaluateAndAlert()` on a 5-minute cadence
- Added `runRetentionCleanup` onSchedule export that deletes rows older than 30 days from `service_health_checks`, `alert_events`, and `document_processing_events` in parallel
- Both functions use dynamic `import()` pattern and list all required Firebase secrets explicitly
- All 64 existing tests continue to pass

## Task Commits

Both tasks modified the same file in a single edit operation:

1. **Task 1: Add runHealthProbes** - `1f9df62` (feat) — includes both Task 1 and Task 2
2. **Task 2: Add runRetentionCleanup** — included in `1f9df62` above

**Plan metadata:** (docs commit forthcoming)

## Files Created/Modified
- `backend/src/index.ts` - Added `runHealthProbes` and `runRetentionCleanup` scheduled Cloud Function exports after `processDocumentJobs`

## Decisions Made
- Combined both exports into one commit since they were added simultaneously to the same file — functionally equivalent to two separate commits
- `retryCount: 0` on `runHealthProbes` — with a 5-minute schedule, a failed probe run is superseded by the next run before any retry would be useful
- `timeoutSeconds: 120` on `runRetentionCleanup` — cleanup may process large batches; 60 seconds could be tight for large datasets

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None — TypeScript compiled cleanly on first pass, all tests passed.

## User Setup Required
None - no external service configuration required. Firebase deployment will pick up the new exports automatically.

## Next Phase Readiness
- All Phase 2 backend service plans complete (02-01 through 02-04)
- Ready for Phase 3 API layer development
- Health probe infrastructure fully wired: probes run on schedule, alerts sent via email, data retained for 30 days
- Monitoring system is operational end-to-end

---
*Phase: 02-backend-services*
*Completed: 2026-02-24*