Horizontally scaling chat app

App Overview

Features

• Send and receive messages
• Show current connection count

Technologies

1. Typescript
2. Fastify - Backend
3. Websockets - Realtime
4. Next.js - Frontend
5. Tailwind & Shadcn UI - Styling
6. Redis - Pub/Sub
7. Caddy - Load Balancer
8. Docker/docker-compose - Containerization
9. GitHub actions - CI/CD
10. DigitalOcean - Host the backend
11. Vercel - Host the frontend

Local setup

git clone https://github.com/Ajaydeep123/Chat_anon.git
cd Chat_anon

• Change the url in the Caddyfile

{
    debug
}

http://127.0.0.1 {
    reverse_proxy chat-app-1:3001 chat-app-2:4000 chat-app-3:5000 {
        header_down Strict-Transport-Security max-age=315360000
    }
}

• Run the backend server

cd chatapp
pnpm install
vi run.sh  // create a run.sh script and fill the details form example.run.sh file
./run.sh

• Run the client

cd ..
cd ui
pnpm install
pnpm dev

Summary

The provided code is a Node.js server built with the Fastify web framework, incorporating real-time communication with clients via websockets and using Redis as a message broker.
We are using Caddy as Load Balancer. The reverse_proxy directive in the Caddyfile is being used to distribute incoming requests evenly among the available instances of the chat application. The header_down directive can be used to set the Strict-Transport-Security header for added security.