[orchestrator] Productionize todo list application - full stack integration

[devin-ai-integration]

Summary

Transforms the prototype in-memory todo list into a production-ready application. Work was parallelized across 4 child Devin agent sessions, each on a separate branch, then merged sequentially into productionize:

1. Service Infrastructure — PostgreSQL integration with migrations, Dockerfiles (backend + frontend), docker-compose.yml, CI/CD pipelines (GitHub Actions), Prometheus metrics, structured logging (Winston), correlation ID tracing, Kubernetes manifests (k8s/), health/readiness endpoints
2. Application Core — JWT authentication (register/login/refresh/logout), bcrypt password hashing, input validation (express-validator), security hardening (helmet, rate limiting, CSRF, XSS sanitization, HTTPS redirect), centralized error handling, updated frontend with auth UI
3. Unit Tests — Jest test suite for todo CRUD routes, server config, and resetStore helper; coverage reporting with 80% threshold
4. E2E Tests — Playwright browser tests, Supertest API integration tests, post-deployment smoke test script, docker-compose.test.yml
5. Orchestrator (this PR) — Merged all 4 branches with conflict resolution, fixed cross-workstream integration issues, added documentation: README, ARCHITECTURE, DEPLOYMENT, DEVELOPMENT, API, plus existing CONVENTIONS and OBSERVABILITY docs

Each merge involved manual conflict resolution across server.js, package.json, .env.example, route files, and lock files.

Updates since last revision

The orchestrator fixed several integration issues that emerged from merging independently-authored child agent branches:

• Replaced uuid v13.0.0 with crypto.randomUUID() — uuid v13 is ESM-only, incompatible with the CommonJS codebase. Affected: requestLogger.js, correlationId.js, user.js.
• Created tests/unit/helpers/auth.js — Shared test helper that generates JWT tokens and CSRF tokens for authenticated test requests (withAuth(), withAuthAndCsrf()). Includes a fallback module resolution path so the same helper works from both backend/ (unit tests) and project root (integration tests).
• Updated all unit tests (35 tests) — Tests were written against the original prototype (no auth). Wrapped requests with auth/CSRF helpers; updated resetStore() to accept userId for user-scoped data.
• Updated integration tests (15 tests) — Same auth/CSRF wrapping. Changed expected status for missing-text POST from 201→400 (validation now enforced).
• Rewrote smoke test script — smoke-test.sh now registers a user, extracts JWT + CSRF tokens, and includes auth headers on all requests. Added auth enforcement test (unauthenticated → 401). 8 tests total.
• Rewrote E2E Playwright tests — Tests now register a unique user through the frontend UI before each test, then interact with the todo app. 9 tests covering auth flow, CRUD, validation, and error states.
• All 11 CI checks pass (Lint, Test, Integration Tests, E2E Tests, Smoke Tests, Build Backend Image ×2, Build Frontend Image ×2).

Review & Testing Checklist for Human

• Verify server.js merge conflict resolution is correct. This file was merged 4 times (service-infra → app-core → unit-tests → e2e-tests). Check middleware ordering (rate limiting → CSRF → auth → routes), all imports resolve, and no lines were accidentally dropped. Key areas: readiness probe DB check, metrics endpoint, CSRF + auth middleware ordering, and the /* istanbul ignore next */ guard.
• Run docker compose up --build and test the full stack manually. The Dockerfiles, nginx config, and compose file were authored by the service-infra agent independently from the app-core agent's middleware changes. Confirm backend connects to PostgreSQL, migrations run, and frontend proxies correctly.
• Verify the auth test helpers aren't masking real issues. The test helper (tests/unit/helpers/auth.js) hardcodes the JWT secret as dev-jwt-secret-change-in-production and uses a fallback require() path for jsonwebtoken. If the default secret or module structure changes, all tests will break. The CSRF token generation uses a simple random token that bypasses the real CSRF middleware's cookie-setting flow — confirm this doesn't hide CSRF bugs.
• Check consistency between root and backend package.json. Root has jest@^29.7.0 (from e2e agent) while backend has jest@^30.3.0 (from unit-test agent). Confirm these don't conflict.
• Test the auth flow end-to-end manually. Register a user, login, create/read/update/delete todos, verify user isolation (user A can't see user B's todos). The frontend hardcodes API_BASE = 'http://localhost:3000' — not configurable via env var.

Recommended test plan: Clone the branch, run docker compose up --build, open http://localhost:8080, register a user, create todos, then separately run cd backend && npm test, npm run test:integration, and npm run test:e2e from the root.

Notes

• CI/CD deploy steps in cd.yml are scaffolded (echo-only) — real deployment commands need to be added per your infrastructure.
• K8s secret.yaml contains base64 placeholder values that must be replaced before applying to a cluster.
• The TODO_APP_JWT_SECRET and TODO_APP_DB_PASSWORD in .env.example are intentionally placeholder values.
• Two logger implementations exist: backend/config/logger.js (Winston, from app-core) and backend/utils/logger.js (from service-infra). The integrated server uses config/logger. Confirm utils/logger.js is still needed or can be removed.
• The smoke test script extracts tokens from JSON responses using grep -o pattern matching, which is fragile if the response format changes.

Link to Devin session: https://partner-workshops.devinenterprise.com/sessions/a6475abe5b424e218d94266dafbd12d2

[devin-ai-integration]

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