Socket.IO cluster adapter

The @socket.io/cluster-adapter package allows broadcasting packets between multiple Socket.IO servers.

!Adapter diagram

It can be used in conjunction with @socket.io/sticky to broadcast packets between the workers of the same Node.js cluster.

Supported features:

- broadcasting
- utility methods
- socketsJoin
- socketsLeave
- disconnectSockets
- fetchSockets
- serverSideEmit

Related packages:

- Postgres adapter: https://github.com/socketio/socket.io-postgres-adapter/
- Redis adapter: https://github.com/socketio/socket.io-redis-adapter/
- MongoDB adapter: https://github.com/socketio/socket.io-mongo-adapter/

Table of contents

- Installation
- Usage
- License

Installation

``
npm install @socket.io/cluster-adapter
`

Usage

`js
const cluster = require("cluster");
const http = require("http");
const { Server } = require("socket.io");
const numCPUs = require("os").cpus().length;
const { setupMaster, setupWorker } = require("@socket.io/sticky");
const { createAdapter, setupPrimary } = require("@socket.io/cluster-adapter");

if (cluster.isMaster) {
console.log(Master ${process.pid} is running);

const httpServer = http.createServer();

// setup sticky sessions
setupMaster(httpServer, {
loadBalancingMethod: "least-connection",
});

// setup connections between the workers
setupPrimary();

// needed for packets containing buffers (you can ignore it if you only send plaintext objects)
// Node.js < 16.0.0
cluster.setupMaster({
serialization: "advanced",
});
// Node.js > 16.0.0
// cluster.setupPrimary({
// serialization: "advanced",
// });

httpServer.listen(3000);

for (let i = 0; i < numCPUs; i++) {
cluster.fork();
}

cluster.on("exit", (worker) => {
console.log(Worker ${worker.process.pid} died);
cluster.fork();
});
} else {
console.log(Worker ${process.pid} started);

const httpServer = http.createServer();
const io = new Server(httpServer);

// use the cluster adapter
io.adapter(createAdapter());

// setup connection with the primary process
setupWorker(io);

io.on("connection", (socket) => {
/ ... /
});
}
``

License

MIT