How does one start a node.js server as a daemon process?

Question

In Python Twisted, you have the twistd command that helps you with a number of things related to running your application (daemonize it for example).

Ho

Answer 1

If you need your process to daemonize itself, not relaying on forever - you can use the daemonize module.

$ npm install daemonize2

Then just write your server file as in example:

var daemon = require("daemonize2").setup({
    main: "app.js",
    name: "sampleapp",
    pidfile: "sampleapp.pid"
});

switch (process.argv[2]) {

    case "start":
        daemon.start();
        break;

    case "stop":
        daemon.stop();
        break;

    default:
        console.log("Usage: [start|stop]");
}

Mind you, that's rather a low level approach.

Answer 2

To start a systemd service manager daemon, write a service file. For example, create a file /etc/systemd/system/myservice.service.

[Unit]
Description=myservice-description
After=network.target

[Service]
ExecStart=/opt/myservice-location/src/node/server.js --args=here
Restart=always
User=me
Group=group
Environment=PATH=/usr/bin:/usr/local/bin
Environment=NODE_ENV=production
WorkingDirectory=/opt/myservice-location

[Install]
WantedBy=multi-user.target

Remember to update the service manager daemon after every change to the myservice.service file.

$ systemctl daemon-reload

Then start the service running and enable the service to start at boot.

$ systemctl start myservice
$ systemctl enable myservice

Answer 3

For the background on the normal way to daemonise on a POSIX system you can search for the C method.

I have not seen enough methods in the node.js API to allow it to be done the C way by hand. However, when using child_process, you can have node.js do it for you:

http://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options

I consider this a potential waste of time because there's a good chance your system provides the same.

For example:

http://libslack.org/daemon/manpages/daemon.1.html

If you want something portable (cross platform) the other posts offer solutions that might suffice.

Answer 4

There are more advanced general-purpose runners, such as monit and runit.

Answer 5

You can try:

$ nohup node server.js &

It work for me on Mac and Linux.

The output will be in the ./nohup.out file

But I still recommend you use pm2 or forever, because they are easily used for restarting, stopping and logging.

Answer 6

Forever is answer to your question.

Install

$ curl https://npmjs.org/install.sh | sh
$ npm install forever
# Or to install as a terminal command everywhere:
$ npm install -g forever

Usage

Using Forever from the command line

$ forever start server.js

Using an instance of Forever from Node.js

var forever = require('forever');

  var child = new forever.Forever('your-filename.js', {
    max: 3,
    silent: true,
    args: []
  });

  child.on('exit', this.callback);
  child.start();