101 lines
2.7 KiB
Markdown
101 lines
2.7 KiB
Markdown
# Socket.IO cluster adapter
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The `@socket.io/cluster-adapter` package allows broadcasting packets between multiple Socket.IO servers.
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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).
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Supported features:
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- [broadcasting](https://socket.io/docs/v4/broadcasting-events/)
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- [utility methods](https://socket.io/docs/v4/server-instance/#Utility-methods)
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- [`socketsJoin`](https://socket.io/docs/v4/server-instance/#socketsJoin)
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- [`socketsLeave`](https://socket.io/docs/v4/server-instance/#socketsLeave)
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- [`disconnectSockets`](https://socket.io/docs/v4/server-instance/#disconnectSockets)
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- [`fetchSockets`](https://socket.io/docs/v4/server-instance/#fetchSockets)
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- [`serverSideEmit`](https://socket.io/docs/v4/server-instance/#serverSideEmit)
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Related packages:
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- Postgres adapter: https://github.com/socketio/socket.io-postgres-adapter/
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- Redis adapter: https://github.com/socketio/socket.io-redis-adapter/
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- MongoDB adapter: https://github.com/socketio/socket.io-mongo-adapter/
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**Table of contents**
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- [Installation](#installation)
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- [Usage](#usage)
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- [License](#license)
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## Installation
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```
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npm install @socket.io/cluster-adapter
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```
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## Usage
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```js
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const cluster = require("cluster");
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const http = require("http");
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const { Server } = require("socket.io");
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const numCPUs = require("os").cpus().length;
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const { setupMaster, setupWorker } = require("@socket.io/sticky");
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const { createAdapter, setupPrimary } = require("@socket.io/cluster-adapter");
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if (cluster.isMaster) {
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console.log(`Master ${process.pid} is running`);
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const httpServer = http.createServer();
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// setup sticky sessions
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setupMaster(httpServer, {
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loadBalancingMethod: "least-connection",
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});
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// setup connections between the workers
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setupPrimary();
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// needed for packets containing buffers (you can ignore it if you only send plaintext objects)
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// Node.js < 16.0.0
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cluster.setupMaster({
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serialization: "advanced",
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});
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// Node.js > 16.0.0
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// cluster.setupPrimary({
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// serialization: "advanced",
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// });
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httpServer.listen(3000);
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for (let i = 0; i < numCPUs; i++) {
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cluster.fork();
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}
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cluster.on("exit", (worker) => {
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console.log(`Worker ${worker.process.pid} died`);
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cluster.fork();
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});
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} else {
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console.log(`Worker ${process.pid} started`);
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const httpServer = http.createServer();
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const io = new Server(httpServer);
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// use the cluster adapter
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io.adapter(createAdapter());
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// setup connection with the primary process
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setupWorker(io);
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io.on("connection", (socket) => {
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/* ... */
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});
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}
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```
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## License
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[MIT](LICENSE)
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