NodeJS Graceful shutdown of a HTTP server

index.js

'use strict';
const http = require('http');

function addGracefulShutdown(server) {
  const oldClose = server.close;
  const connections = {};
  let shouldDestroy = false;
  let connectionId = 0;

  function destroy(socket) {
    if (socket._isIdle && shouldDestroy) {
      socket.destroy();
      delete connections[socket._connectionId];
    }
  }

  server.on('request', function(req, res) {
    req.socket._isIdle = false;

    res.on('finish', function() {
      req.socket._isIdle = true;
      destroy(req.socket);
    });
  });

  server.on('connection', function(socket) {
    let id = connectionId++;
    socket._isIdle = true;
    socket._connectionId = id;
    connections[id] = socket;

    socket.on('close', function() {
      delete connections[id];
    });
  });

  server.close = function(cb) {
    shouldDestroy = true;
    oldClose.apply(server, function() {
      let args = arguments;
      process.nextTick(function() {
        cb(arguments);
      });
    });

    Object.keys(connections).forEach(key => {
      destroy(connections[key]);
    });
  };

  return server;
}

function extendPrototype() {
  http.Server.prototype.extendClose = function() {
    return addGracefulShutdown(this);
  }
};

extendPrototype();



const server = http.createServer(function(req, res) {
  setTimeout(function() {
    res.writeHead(200);
    res.end('AWesome');
  }, 1000 * 5);
}).extendClose();


server.listen(4242, () => console.log('Listening!'));

process.on('SIGINT', function() {
  console.log('SIGINT received');

  server.close(function(err) {
    console.log('Whats good in the hood!?!?');
    process.exit();
  });
})