https://github.com/socketio/socket.io-cluster-adapter

The Socket.IO official cluster adapter, allowing to broadcast events between several Socket.IO servers.
https://github.com/socketio/socket.io-cluster-adapter

cluster socket-io websocket

Last synced: 4 days ago
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The Socket.IO official cluster adapter, allowing to broadcast events between several Socket.IO servers.

• Host: GitHub
• URL: https://github.com/socketio/socket.io-cluster-adapter
• Owner: socketio
• License: mit
• Created: 2021-06-21T09:15:04.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2023-07-09T08:05:24.000Z (over 1 year ago)
• Last Synced: 2025-01-29T13:03:51.239Z (10 days ago)
• Topics: cluster, socket-io, websocket
• Language: TypeScript
• Homepage: https://socket.io
• Size: 140 KB
• Stars: 18
• Watchers: 3
• Forks: 11
• Open Issues: 7
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Socket.IO cluster adapter

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

![Adapter diagram](./assets/adapter.png)

It can be used in conjunction with [`@socket.io/sticky`](https://github.com/socketio/socket.io-sticky) to broadcast packets between the workers of the same Node.js [cluster](https://nodejs.org/api/cluster.html).

Supported features:

- [broadcasting](https://socket.io/docs/v4/broadcasting-events/)

- [utility methods](https://socket.io/docs/v4/server-instance/#Utility-methods)

  - [`socketsJoin`](https://socket.io/docs/v4/server-instance/#socketsJoin)

  - [`socketsLeave`](https://socket.io/docs/v4/server-instance/#socketsLeave)

  - [`disconnectSockets`](https://socket.io/docs/v4/server-instance/#disconnectSockets)

  - [`fetchSockets`](https://socket.io/docs/v4/server-instance/#fetchSockets)

  - [`serverSideEmit`](https://socket.io/docs/v4/server-instance/#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](#installation)

- [Usage](#usage)

- [License](#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](LICENSE)