docs: simplify nginx cluster example

- remove useless Dockerfile
- clean format
- migrate to @socket.io/redis-adapter

Author: darrachequesne

examples/cluster-nginx/docker-compose.yml

@@ -1,6 +1,8 @@
 
 nginx:
-  build: ./nginx
+  image: nginx:alpine
+  volumes:
+    - ./nginx.conf:/etc/nginx/nginx.conf:ro
   links:
     - server-john
     - server-paul

examples/cluster-nginx/nginx/nginx.conf renamed to examples/cluster-nginx/nginx.conf

@@ -1,15 +1,18 @@
-// Setup basic express server
-var express = require('express');
-var app = express();
-var server = require('http').createServer(app);
-var io = require('socket.io')(server);
-var redis = require('socket.io-redis');
-var port = process.env.PORT || 3000;
-var serverName = process.env.NAME || 'Unknown';
+const express = require('express');
+const app = express();
+const server = require('http').createServer(app);
+const io = require('socket.io')(server);
+const { createAdapter } = require('@socket.io/redis-adapter');
+const { createClient } = require('redis');
+const port = process.env.PORT || 3000;
+const serverName = process.env.NAME || 'Unknown';
 
-io.adapter(redis({ host: 'redis', port: 6379 }));
+const pubClient = createClient({ host: 'redis', port: 6379 });
+const subClient = pubClient.duplicate();
 
-server.listen(port, function () {
+io.adapter(createAdapter(pubClient, subClient));
+
+server.listen(port, () => {
   console.log('Server listening at port %d', port);
   console.log('Hello, I\'m %s, how can I help?', serverName);
 });
@@ -19,15 +22,15 @@ app.use(express.static(__dirname + '/public'));
 
 // Chatroom
 
-var numUsers = 0;
+let numUsers = 0;
 
-io.on('connection', function (socket) {
+io.on('connection', socket => {
   socket.emit('my-name-is', serverName);
 
-  var addedUser = false;
+  let addedUser = false;
 
   // when the client emits 'new message', this listens and executes
-  socket.on('new message', function (data) {
+  socket.on('new message', data => {
     // we tell the client to execute 'new message'
     socket.broadcast.emit('new message', {
       username: socket.username,
@@ -36,7 +39,7 @@ io.on('connection', function (socket) {
   });
 
   // when the client emits 'add user', this listens and executes
-  socket.on('add user', function (username) {
+  socket.on('add user', username => {
     if (addedUser) return;
 
     // we store the username in the socket session for this client
@@ -54,21 +57,21 @@ io.on('connection', function (socket) {
   });
 
   // when the client emits 'typing', we broadcast it to others
-  socket.on('typing', function () {
+  socket.on('typing', () => {
     socket.broadcast.emit('typing', {
       username: socket.username
     });
   });
 
   // when the client emits 'stop typing', we broadcast it to others
-  socket.on('stop typing', function () {
+  socket.on('stop typing', () => {
     socket.broadcast.emit('stop typing', {
       username: socket.username
     });
   });
 
   // when the user disconnects.. perform this
-  socket.on('disconnect', function () {
+  socket.on('disconnect', () => {
     if (addedUser) {
       --numUsers;
 

examples/cluster-nginx/nginx/Dockerfile

@@ -7,9 +7,10 @@
   "private": true,
   "license": "MIT",
   "dependencies": {
+    "@socket.io/redis-adapter": "^7.0.1",
     "express": "4.13.4",
-    "socket.io": "^4.0.0",
-    "socket.io-redis": "^6.0.1"
+    "redis": "^3.1.2",
+    "socket.io": "^4.0.0"
   },
   "scripts": {
     "start": "node index.js"