NestJS Microservices Project

A scalable microservices architecture showcasing service communication, database management, and containerization using NestJS, MySQL, and Docker.

System Architecture

Our microservices ecosystem consists of:

1. API Gateway (Port 4000)

• Central entry point for all client requests
• Routes traffic to appropriate microservices
• Handles request/response transformation
• Swagger API documentation
• Load balancing and service discovery

2. User Service (Port 4001)

• Manages user-related operations
• Features:
  • User registration and authentication
  • Profile management
  • JWT token handling
• Dedicated MySQL instance (Port 3307)

3. Post Service (Port 4002)

• Handles all post-related operations
• Features:
  • Create, read, update, delete posts
  • Post metadata management
  • Content validation
• Dedicated MySQL instance (Port 3308)

Technology Stack

• Framework: NestJS with TypeScript
• Databases: MySQL 8.0
• Containerization: Docker & Docker Compose
• Documentation: Swagger/OpenAPI
• Testing: Jest & Supertest
• Node Version: 18.x

Getting Started

Prerequisites

• Docker Desktop
• Node.js 18+
• npm 8+

Installation

1. Clone the repository:

git clone <your-repo-url>
cd microservice-nest-js

2. Set up environment variables:

Create .env for User Service:

DB_HOST=user-db
DB_PORT=3306
DB_USERNAME=root
DB_PASSWORD=password
DB_DATABASE=user_service_db

Create .env for Post Service:

DB_HOST=post-db
DB_PORT=3306
DB_USERNAME=root
DB_PASSWORD=password
DB_DATABASE=post_service_db

3. Start the services:

# Build and start all services
docker-compose up -d --build

4. Verify the deployment:

# Check running containers
docker ps

# Check service logs
docker-compose logs -f

Service URLs

• API Gateway: http://localhost:4000
• User Service: http://localhost:4001
• Post Service: http://localhost:4002

Development

Local Development

# Install dependencies for each service
cd api-gateway && npm install
cd ../user-service && npm install
cd ../post-service && npm install

# Run services in development mode
npm run start:dev

Docker Commands

# Start services
docker-compose up -d

# Rebuild a specific service
docker-compose up -d --build [service-name]

# View logs
docker-compose logs -f [service-name]

# Stop all services
docker-compose down

# Clean up volumes
docker-compose down -v

API Documentation

Access Swagger documentation at:

• Gateway API: http://localhost:4000/api
• User Service: http://localhost:4001/api
• Post Service: http://localhost:4002/api

Testing

Run tests for each service:

# Unit tests
npm test

# E2E tests
npm run test:e2e

# Test coverage
npm run test:cov

Troubleshooting

Common Issues

1. Database Connection Failures

   • Check if MySQL containers are healthy
   • Verify environment variables
   • Ensure ports are not in use

2. Service Discovery Issues

   • Check if all services are running
   • Verify network connectivity
   • Check service names in docker-compose.yml

3. Build Failures

   • Clear Docker cache: docker builder prune
   • Remove node_modules: rm -rf node_modules
   • Rebuild: docker-compose up -d --build

Contributing

1. Fork the repository
2. Create your feature branch: git checkout -b feature/amazing-feature
3. Commit your changes: git commit -m 'Add amazing feature'
4. Push to the branch: git push origin feature/amazing-feature
5. Submit a pull request

License

This project is licensed under the MIT License - see the LICENSE file for details.