Scalable Socket.IO Server with NestJS

A demonstration project showcasing a scalable Socket.IO implementation using NestJS. This project implements a horizontally scalable WebSocket server architecture that can handle real-time communications across multiple server instances.

Architecture

The project consists of the following components:

• Socket.IO Server: NestJS-based WebSocket server with adapter for horizontal scaling
• Consumer Service: NestJS microservice that processes messages and broadcasts them to Socket.IO clients
• Adapters: Used for Socket.IO pub/sub between multiple server instances. eg. Redis
• Message Brokers: for handling event distribution. eg. RabbitMQ

Features

• Horizontally scalable Socket.IO server using adapters
• Message queuing for reliable event processing
• Microservice architecture using NestJS
• Docker containerization for easy deployment
• Receives events from client and emit to message broker

Prerequisites

• Docker and Docker Compose
• Node.js (for local development)
• PNPM package manager

Getting Started

1. Clone the repository:

git clone git@github.com:civilcoder55/scalable-nest-websockets.git
cd scalable-nest-websockets

2. Start the services using Docker Compose:

docker-compose up -d --scale socket-io-server=3

This will start:

• RabbitMQ (Management UI available at http://localhost:15672)
• Redis
• Socket.IO Server (3 instances available at http://localhost:3000, http://localhost:3001, http://localhost:3002)
• Consumer Service

Testing the Setup

1. Connect to the Socket.IO server using a socket.io client (e.g., Postman)
2. Send a message to RabbitMQ's 'notification' queue
3. The consumer will process the message and broadcast it via Socket.IO
4. All connected clients will receive the notification

Environment Variables

Socket.IO Server

• REDIS_URL: Redis connection URL

Consumer Service

• RABBITMQ_URL: RabbitMQ connection URL
• REDIS_URL: Redis connection URL

Development

For local development:

1. Install dependencies:

pnpm install

2. Start services in development mode:

# Terminal 1 - Start dependencies
docker-compose up redis rmq

# Terminal 2 - Start Socket.IO server
cd socket-io-server
pnpm run start:dev

# Terminal 3 - Start consumer
cd consumer
pnpm run start:dev

Contributing

Feel free to submit issues, fork the repository, and create pull requests for any improvements.

License

MIT License