How to work with nginx?

[superzmx]

Hello,

Socket.io works well when requested directly with the example:

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();

  setupMaster(httpServer, {
    loadBalancingMethod: "least-connection", // either "random", "round-robin" or "least-connection"
  });

  setupPrimary();

  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);
  io.adapter(createAdapter());
  setupWorker(io);

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

but once reversed by nginx with followed config:

http {
  server {
    listen 80;
    root /var/www/html;

    location / {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $host;

      proxy_pass http://ip:3000;

      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "upgrade";
    }
  }
}

It failed with 404 response:

How can I proxy socket.io-sticky with cluster module properly

[cmizzi]

Hello. I have the same issue while testing polling transport only. My implementation is almost the same as yours, but I'm using the Redis adapter instead of the cluster adapter. I tried different implementations, but the issue seems to come from this package directly (probably related to keep-alive header?).