ws memory leak demo

client.js

/**
 * The client opens 10,000 connections to the server and sends one 10k message.
 * Every minutes, 2,000 new connections are openend and 2,000 random connections
 * are closed (equally distributed interval).
 */

var util = require('util')
  , WebSocket = require('ws');

// Config
var config = {
    host: 'localhost'
  , port: 10080
  , concurrency: 10000
  , connectionsPerMinute: 2000
};

// Stats
var stats = {
    clientsTotal: 0
  , clientsCurrent: 0
  , messagesSent: 0
  , messagesReceived: 0
  , wsErrors: 0
};

// Connected clients
var clients = [];

// Display stats every second
setInterval(function() {
  util.log(util.inspect(stats));
  util.log(util.inspect(process.memoryUsage()));
}, 1000);

// Exit after 10 minutes
setTimeout(function() {
  process.exit();
}, 10 * 60 * 1000);

// Initially open 20.000 connections
for (var i = 0; i < config.concurrency; i++) {
  openWs();
}

// Open and close WS connections
setInterval(openWs, Math.ceil(60 * 1000 / config.connectionsPerMinute));
setInterval(closeWs, Math.ceil(60 * 1000 / config.connectionsPerMinute));

// Open a connection
function openWs() {
  var ws = new WebSocket('ws://' + config.host + ':' + config.port + '/');
  
  ws.on('error', function(e) {
    stats.wsErrors++;
  });

  ws.on('open', function() {
    clients.push(ws);
    stats.clientsTotal++;
    stats.clientsCurrent++;

    ws.on('message', function(data) {
      stats.messagesReceived++;
    });
    
    ws.on('close', function() {
      stats.clientsCurrent--;
      var index = clients.indexOf(ws);
      if (index != -1) {
        clients.splice(index, 1);
      }
    });

    // Send 10k message
    ws.send(new Array(2000).join("XXXXX"));
    stats.messagesSent++;
  });
}

// Close a random connection
function closeWs() {
  if (clients.length > 0) {
    var index = Math.floor(Math.random() * (clients.length - 1));
    clients[index].close();
  }
}

server.js

/**
 * This ws server only accepts connections and sends "something" to the client. 
 * Every second, client count and memory usage is displayed as CSV.
 *
 * You might have to 
 *   echo "* hard nofile 65536" >> /etc/security/limits.d/local.conf
 *   ulimit -n 30000
 */

var WebSocketServer = require('ws').Server
  , wss = new WebSocketServer({port: 10080});

var clientsCount = 0;

console.log('clients,rss,heapTotal,heapUsed');

setInterval(function() {
  console.log('%d,%d,%d,%d', clientsCount,
    process.memoryUsage().rss,
    process.memoryUsage().heapTotal,
    process.memoryUsage().heapUsed);
}, 10000);

wss.on('connection', function(ws) {
  clientsCount++;
  ws.on('message', function(message) {});
  ws.send('something');
  ws.on('close', function() {
    clientsCount--;
  })
});