Snapnet is a scalable workforce-management backend built with NestJS, TypeORM (MySQL), RabbitMQ (job queueing), and Redis (cache/idempotency). Key features implemented in this repo:

• REST APIs for departments, employees, leave requests (Swagger docs at /api/docs)
• Messaging with RabbitMQ via @golevelup/nestjs-rabbitmq:
  • Producer: publish leave.requested, user.registered
  • Consumers: leave request processor (auto-approve short leaves ≤ 2 days), email worker (welcome email)
  • Retry strategies (exponential / fixed) and configurable retry policies
  • Dead-lettering to DLQ on exhaustion
• Idempotency via Redis.setNxExpire for workers (prevents duplicate updates)
• Health endpoints:
  • GET /api/health — liveness
  • GET /api/queue-health — checks Redis + RabbitMQ (requires ADMIN role)
• Authentication and roles guard (routes protected via @Roles(Role.ADMIN) and RolesGuard)
• Unit and integration tests (Jest + Supertest). Queue-integration tests can run against mocked or real RabbitMQ.
• TypeORM-based migrations with CLI in package.json (migration:run / migration:generate)

• Health controller/service: src/health/health.controller.ts, src/health/health.service.ts
• Messaging: src/job-queue/producer.service.ts, src/job-queue/email.processor.ts
• Redis abstraction: src/redis/redis.service.ts
• Config abstraction: src/utils/common/config/config.service.ts
• App entry: src/app.module.ts
• Tests: tests live in test/ and src/**/*.spec.ts

• Node >= 18, npm or yarn
• Docker & Docker Compose (for local DB & message broker)
• Optional: MySQL client for inspection

Create a .env at project root with the following (example):

• APP_URL=http://localhost
• PORT=3000
• NODE_ENV=development

Database

• DB_HOST (default: localhost)
• DB_PORT (default: 3306)
• DB_USERNAME
• DB_PASSWORD
• DB_NAME

Redis

• REDIS_HOST
• REDIS_PORT
• REDIS_PASSWORD (optional)
• REDIS_DB

RabbitMQ

• RABBITMQ_URL (e.g. amqp://guest:guest@localhost:5672)
• RABBITMQ_EXCHANGE (default: workforce.events)
• RABBITMQ_DLQ (DLQ routing key/exchange name)

Retry & queues

• RETRY_STRATEGY (fixed|exponential)
• RETRY_FIXED_DELAY_MS
• RETRY_BASE_MS
• RETRY_CAP_MS
• EMAIL_MAX_RETRIES

1. Clone repo and install dependencies:
   • Windows PowerShell:
     • npm install
2. Copy example env:
   • copy .env.example .env (if .env.example present) or create .env with variables above
3. Start supporting services (MySQL + RabbitMQ) with Docker Compose:
   • docker-compose up -d
   • Wait until MySQL & RabbitMQ healthy (docker-compose ps / docker logs)
4. Run DB migrations:
   • npm run migration:run
   • (To generate a new migration file: npm run migration:generate -- -n MigrationName)
5. Start app:
   • npm run start:dev
6. Swagger UI:
   • Open {APP_URL}/api/docs (configured in src/main.ts)

• Unit & integration (uses Jest):
  • npm test
• To run tests with services from Docker Compose:
  • docker-compose -f docker-compose.yml up -d
  • npm test

• Migrations implemented via TypeORM CLI helper in package.json; TypeScript migrations in src/database/migrations.
• Use npm run migration:generate to produce migration files and npm run migration:run to apply them.

• Tests mock RabbitMQ by default for speed. To run tests against an actual broker:
  • Start RabbitMQ with docker-compose
  • Ensure RABBITMQ_URL points to running broker
  • Run tests

• GET /api/health — public
• GET /api/queue-health — protected; requires ADMIN role (decorator/guard in src/decorators/role.decorator.ts and src/guards/roles.guard.ts)

See the Docker files included in the repository root:

• Dockerfile — application image build
• .dockerignore — reduce image size
• docker-compose.yml — default dev stack (MySQL + RabbitMQ)
• docker-compose.test.yml — stack optimized for CI/tests

• If migrations fail: verify DB credentials and network access (docker-compose logs db).
• If RabbitMQ connection fails: check RABBITMQ_URL and firewall; management UI at http://localhost:15672 (guest/guest).
• For Redis issues: ensure REDIS_HOST/REDIS_PORT set and service running.

• Health controller: src/health/health.controller.ts
• Health service: src/health/health.service.ts
• Producer: src/job-queue/producer.service.ts
• Email worker: src/job-queue/email.processor.ts
• Redis service: src/redis/redis.service.ts
• Config: src/utils/common/config/config.service.ts