How do I shutdown a Node.js http(s) server immediately?

The trick is that you need to subscribe to the server’s connection event which gives you the socket of the new connection. You need to remember this socket and later on, directly after having called server.close(), destroy that socket using socket.destroy().

Additionally, you need to listen to the socket’s close event to remove it from the array if it leaves naturally because its keep-alive timeout does run out.

I have written a small sample application you can use to demonstrate this behavior:

// Create a new server on port 4000
var http = require('http');
var server = http.createServer(function (req, res) {
  res.end('Hello world!');
}).listen(4000);

// Maintain a hash of all connected sockets
var sockets = {}, nextSocketId = 0;
server.on('connection', function (socket) {
  // Add a newly connected socket
  var socketId = nextSocketId++;
  sockets[socketId] = socket;
  console.log('socket', socketId, 'opened');

  // Remove the socket when it closes
  socket.on('close', function () {
    console.log('socket', socketId, 'closed');
    delete sockets[socketId];
  });

  // Extend socket lifetime for demo purposes
  socket.setTimeout(4000);
});

// Count down from 10 seconds
(function countDown (counter) {
  console.log(counter);
  if (counter > 0)
    return setTimeout(countDown, 1000, counter - 1);

  // Close the server
  server.close(function () { console.log('Server closed!'); });
  // Destroy all open sockets
  for (var socketId in sockets) {
    console.log('socket', socketId, 'destroyed');
    sockets[socketId].destroy();
  }
})(10);

Basically, what it does is to start a new HTTP server, count from 10 to 0, and close the server after 10 seconds. If no connection has been established, the server shuts down immediately.

If a connection has been established and it is still open, it is destroyed.
If it had already died naturally, only a message is printed out at that point in time.