systemd for Node.js

Adds support for running node.js as a socket-activated service under systemd.

More info on the how and why: https://rocketeer.be/articles/deploying-node-js-with-systemd/

For more background on socket activation: http://0pointer.de/blog/projects/socket-activation.html

Obviously, this will only work on Linux distributions with systemd (such as Fedora).

Usage

You can install the latest version via npm:

``sh
$ npm install systemd
`

Require the systemd module and pass 'systemd' as a parameter to listen():

`javascript
require('systemd');

var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen('systemd');
`

Install a systemd socket file (e.g.: /etc/systemd/system/node-hello.socket):

`ini
[Socket]
ListenStream=1337

[Install]
WantedBy=sockets.target
`

Install a systemd service file (e.g.: /etc/systemd/system/node-hello.service):

`ini


Adjust according to man 5 systemd.exec

[Service]
ExecStart=/path/to/bin/node /path/to/hello.js
StandardOutput=syslog
User=nobody
Group=nobody
`

Be sure to substitute the paths to node and your script!

* ⚠ __Run node directly__ or make sure your startup helper scripts
can hand over the sockets. npm start [probably won't work][issue-11].

[issue-11]: https://github.com/rubenv/node-systemd/issues/11

Reload the systemd daemon so that it picks up the new unit files:

`sh
$ systemctl --system daemon-reload
`

Enable and start the socket:

`sh
$ systemctl enable node-hello.socket
$ systemctl start node-hello.socket
`

Check the status of the socket:

`sh
$ systemctl status node-hello.socket
node-hello.socket
Loaded: loaded (/etc/systemd/system/node-hello.socket)
Active: active (listening) since Sat, 15 Oct 2011 20:27:47 +0200; 2s ago
CGroup: name=systemd:/system/node-hello.socket
`

Great, it's running!

Check the status of the service, not running yet:

`sh
$ systemctl status node-hello.service
node-hello.service
Loaded: loaded (/etc/systemd/system/node-hello.service)
Active: inactive (dead)
CGroup: name=systemd:/system/node-hello.service
`

Do a request to your service:

`sh
$ curl -i http://localhost:1337/
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: keep-alive
Transfer-Encoding: chunked

Hello World
`

Check again, now it will be running:

`sh
$ systemctl status node-hello.service
node-hello.service
Loaded: loaded (/etc/systemd/system/node-hello.service)
Active: active (running) since Sat, 15 Oct 2011 20:32:10 +0200; 38s ago
Main PID: 1159 (node)
CGroup: name=systemd:/system/node-hello.service
└ 1159 /path/to/bin/node /path/to/hello.js
`

Only listen to systemd when running under systemd

You can make the systemd usage conditional by checking for the systemd environment variable:

`javascript
var http = require('http');

require('systemd');

var port = process.env.LISTEN_PID > 0 ? 'systemd' : 1337;
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(port);
`

This makes it possible to run the script stand-alone in development, yet use systemd when started through systemd.

Contributing

A jshint file is included to check code style.

Before submitting a pull request, please check your code. For convenience, I've also added a grunt file.

Install the dev dependencies:

`sh
$ npm install --dev
`

Install the grunt cli if you haven't already done so:

`sh
$ npm -g install grunt-cli
`

Run it:

`sh
$ grunt
``

License

(The MIT License)

Copyright (C) 2011-2014 by Ruben Vermeersch

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.