Tiny Upstart script to keep a NodeJS process alive

by Jalada

I'm not sure what it is about startup scripts, but people seem intent on complicating them. In my experience the simplest way to keep a non-daemonizing NodeJS app running (on an Ubuntu server) is to use Upstart. Upstart has sensible behaviour and defaults that make it perfect for network services like a NodeJS app.

Here's my example script, which would belong in /etc/init/my-nodejs-server.conf

description "My NodeJS Server"
author "John Appleseed"

env PORT=5001

start on runlevel [2345]
stop on runlevel [016]
respawn

setuid john
chdir /home/john/Applications/my-nodejs-server/
exec node index.js

With this file in place (that's all you need to do!) you could sudo service my-nodejs-server start and it'd be up and running. With this 9 line script we have some powerful configuration already:

  1. We can configure environment variables in a faux 12 factor style.
  2. Our NodeJS app will automatically start on boot, and stop on shutdown.
  3. Upstart will restart the app if it crashes.
  4. It will run as our unpriveleged user 'john'.
  5. Upstart (1.4 and above) will log all output to /var/log/upstart/my-nodejs-server.log which will be rotated by logrotate.
  6. We can manage the lifecycle with sudo service my-nodejs-server {start,stop,restart}.
  7. We can temporarily disable the app from starting on boot with an override file:
    $ echo manual | sudo tee /etc/init/my-nodejs-server.override.

That's a lot of functionality for a 9 line script, and we didn't even need to use a third party NodeJS library like Forever (though you could add that, but I'm not sure why) or make our app daemonize. Upstart also has a massive amount of functionality in some reasonably clear documentation; there's a lot more you can do with it.

So next time you see a 250+ line init.d script for a NodeJS app, remember there is a better way.