cim_summary/.planning/milestones/v1.0-phases/02-backend-services/02-02-SUMMARY.md

phase: 02-backend-services plan: 02 subsystem: infra tags: [health-probes, document-ai, anthropic, firebase-auth, postgres, vitest, nodemailer] # Dependency graph requires: - phase: 01-data-foundation provides: HealthCheckModel.create() for persistence - phase: 02-backend-services plan: 01 provides: Schema and model layer for service_health_checks table provides: - healthProbeService with 4 real API probers (document_ai, llm_api, supabase, firebase_auth) - ProbeResult interface exported for use by health endpoint - runAllProbes orchestrator with fault-tolerant probe isolation - nodemailer installed (needed by Plan 03 alert notifications) affects: [02-backend-services, 02-03-PLAN] # Tech tracking tech-stack: added: [nodemailer@8.0.1, @types/nodemailer] patterns: - Promise.allSettled for fault-tolerant concurrent probe orchestration - firebase-admin verifyIdToken probe distinguishes expected vs unexpected errors - Direct PostgreSQL pool (getPostgresPool) for Supabase probe, not PostgREST - LLM probe uses cheapest model (claude-haiku-4-5) with max_tokens 5 key-files: created: - backend/src/services/healthProbeService.ts - backend/src/tests/unit/healthProbeService.test.ts modified: - backend/package.json (nodemailer + @types/nodemailer added) key-decisions: - "LLM probe uses claude-haiku-4-5 with max_tokens 5 (cheapest available, prevents expensive accidental probes)" - "Supabase probe uses getPostgresPool().query('SELECT 1') not PostgREST client (bypasses caching/middleware)" - "Firebase Auth probe uses verifyIdToken('invalid-token') — always throws, distinguished by error message content" - "Promise.allSettled chosen over Promise.all to guarantee all probes run even if one throws outside try/catch" - "HealthCheckModel.create failure per probe is swallowed with logger.error — probe results still returned to caller" patterns-established: - "Probe pattern: record start time, try real API call, compute latency, return ProbeResult with status/latency_ms/error_message" - "Firebase SDK probe: verifyIdToken always throws; 'argument'/'INVALID'/'Decoding' in message = SDK alive = healthy" - "429 rate limit errors = degraded (not down) — service is alive but throttling" - "vi.mock with inline vi.fn() in factory — no outer variable references (Vitest hoisting TDZ safe)" requirements-completed: [HLTH-02, HLTH-04] # Metrics duration: 18min completed: 2026-02-24

Phase 02 Plan 02: Health Probe Service Summary

Four real authenticated API probers (Document AI, LLM claude-haiku-4-5, Supabase pg pool, Firebase Auth) with fault-tolerant orchestrator and Supabase persistence via HealthCheckModel

Performance

• Duration: 18 min
• Started: 2026-02-24T14:05:00Z
• Completed: 2026-02-24T14:23:55Z
• Tasks: 2
• Files modified: 4

Accomplishments

• Created healthProbeService.ts with 4 individual probers each making real authenticated API calls
• Implemented runAllProbes orchestrator using Promise.allSettled for fault isolation (one probe failure never blocks others)
• Each probe result persisted to Supabase via HealthCheckModel.create() after completion
• 9 unit tests covering all probers, fault tolerance, 429 degraded handling, Supabase pool verification, and Firebase error discrimination
• Installed nodemailer (needed by Plan 03 alert notifications) to avoid package.json conflicts in parallel execution

Task Commits

Each task was committed atomically:

1. Task 1: Install nodemailer and create healthProbeService - 4129826 (feat)
2. Task 2: Create healthProbeService unit tests - a8ba884 (test)

Plan metadata: (docs commit — created below)

Files Created/Modified

• backend/src/services/healthProbeService.ts - Health probe orchestrator with ProbeResult interface and 4 individual probers
• backend/src/__tests__/unit/healthProbeService.test.ts - 9 unit tests covering all probers and orchestrator
• backend/package.json - nodemailer + @types/nodemailer added

Decisions Made

• LLM probe uses claude-haiku-4-5 with max_tokens: 5 — cheapest Anthropic model prevents accidental expensive probe calls
• Supabase probe uses getPostgresPool().query('SELECT 1') — bypasses PostgREST middleware/caching, tests actual DB connectivity
• Firebase Auth probe strategy: verifyIdToken('invalid-token-probe-check') always throws; error message containing 'argument', 'INVALID', or 'Decoding' = SDK functioning = 'healthy'
• Promise.allSettled over Promise.all — guarantees all 4 probes run even if one rejects outside its own try/catch
• Per-probe persistence failure is swallowed (logger.error only) so probe results are still returned to caller

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None — all probes compiled and tested cleanly on first implementation.

User Setup Required

None - no external service configuration required beyond what's already in .env.

Next Phase Readiness

• healthProbeService.runAllProbes() is ready to be called by the health scheduler (Plan 03)
• nodemailer is installed and ready for Plan 03 alert notification service
• ProbeResult interface exported and ready for use in health status API endpoints

---

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