Express 3 has no "app.close()"

[glynnbird]

Imagine you want to be able to terminate your Node.js app and drain all existing connections before quitting, you might come up with a solution as outlined here:

http://blog.argteam.com/coding/hardening-node-js-for-production-part-3-zero-downtime-deployments-with-nginx

e.g.

• respond to SIGTERM or SIGINT events
• tell your Express app to stop accepting new connections
• get called back by Express when the last connection has been serviced

This would all you to do graceful deployments of new code without terminating existing requests (assuming your load balancer sends traffic to other servers).

As of Express 3, the app.close() method seems to have disappeared, which means Express users have no means of gracefully stopping an application as far as I can see.

[langpavel]

Whole express is in fact stuff around one function; vice versa express app is requestListener for http.createServer(). That is.
Can you look at mechanism you starting your server? This will hint you what you must do.

[aheckmann]

Yes express is really a listener to http request events now which means you can do this:

var app = express();
var server = require('http').createServer(app);
server.listen(1337, function () {
server.close()
})

On Oct 13, 2012, at 1:38 AM, Glynn Bird notifications@github.com wrote:

Imagine you want to be able to terminate your Node.js app and drain all existing connections before quitting, you might come up with a solution as outlined here:

http://blog.argteam.com/coding/hardening-node-js-for-production-part-3-zero-downtime-deployments-with-nginx

e.g.

respond to SIGTERM or SIGINT events
tell your Express app to stop accepting new connections
get called back by Express when the last connection has been serviced
This would all you to do graceful deployments of new code without terminating existing requests (assuming your load balancer sends traffic to other servers).

As of Express 3, the app.close() method seems to have disappeared, which means Express users have no means of gracefully stopping an application as far as I can see.

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Reply to this email directly or view it on GitHub.

[tj]

yup, if you happen to use the "shortcut" app.listen() it now returns an http server wrapped like aaron is showing, var server = app.listen(3000); server.close()

[da99]

So the final full code example for cleaning up resources in Express 3 would be the following?:

var express = require('express');
var app = express();
var server = app.listen(1337);

process.on( 'SIGTERM', function () {

   server.close(function () {
     console.log( "Closed out remaining connections.");
     // Close db connections, etc.
   });

   setTimeout( function () {
     console.error("Could not close connections in time, forcefully shutting down");
     process.exit(1); 
   }, 30*1000);

});

[binarykitchen]

I doubt setTimeout works here after a SIGTERM event because the main event loop won't accept any new events anymore.

[aymericbeaumet]

If anyone ever reaches this issue via Google, the following snippet works with Express 4:

var app = express();

var server = app.listen(8080, function() {
  console.log('Listening :)');
  server.close(function() { console.log('Doh :('); });
});