pixl-boot

Overview

pixl-boot will automatically register a startup service for your module on Linux and OS X, so your daemon will be started on a server reboot. It is configured entirely out of your package.json file, and will handle all the details of registering a systemd service on Linux, or a LaunchAgent/LaunchDaemon on OS X.

This is only designed for packages that are installed as the root user.

Usage

First, add the pixl-boot package in the dependencies section of your package.json file:

"dependencies": {
    "pixl-boot": "^2.0.0"
}

Next, you need to provide a shell script for starting and stopping your background daemon. This can be a simple bash (or Node.js) script that responds to start and stop commands on the CLI. If you do not have one of these scripts we provide a sample one for you (instructions below).

Once you have your control script ready, link to it in the bin property in your package.json file:

"bin": "bin/control.sh",

Finally, you need to have npm run pixl-boot on install and uninstall of your package, so that it has a chance to register and unregister your startup service. Do this by adding postinstall and preuninstall properties in the scripts section of your package.json file:

"scripts": {
    "postinstall": "pixl-boot install",
    "preuninstall": "pixl-boot uninstall"
}

That's it!

Alternatively, if you would rather the startup service not be installed automatically, and instead require additional user commands, change the scripts property names to something custom, like boot and unboot:

"scripts": {
    "boot": "pixl-boot install",
    "unboot": "pixl-boot uninstall"
}

Then your users would need to be instructed to type:

npm run boot
npm run unboot

To install and uninstall the startup service, respectively.

Advanced

The pixl-boot install and pixl-boot uninstall commands accept some optional CLI arguments which you can add if desired:

name

Add --name if you want to customize the startup service name. This defaults to the name property from your package.json file, and is converted to lower-case alphanumeric. Make sure you add this to both the install and uninstall commands. Example:

"scripts": {
    "postinstall": "pixl-boot install --name mycustomservice",
    "preuninstall": "pixl-boot uninstall --name mycustomservice"
}

company

Add --company if you want to customize the "company" (organization) name that goes into your startup service metadata. This defaults to the word Node, and may be displayed as part of your package description, depending on the OS. This is really just a cosmetic detail that has no operational effect on your service. Make sure you add this to both the install and uninstall commands. Example use:

"scripts": {
    "postinstall": "pixl-boot install --company MyCompany",
    "preuninstall": "pixl-boot uninstall --company MyCompany"
}

script

Add --script to specify a custom location of your shell control script, relative to the base directory of your package. Use this option if you do not want to pull this from the bin property in your package.json file. You only need to add this to the pixl-boot install command. Example:

"scripts": {
    "postinstall": "pixl-boot install --script bin/my-control-script.sh"
}

linux_type

Add --linux_type if you want to customize the Linux systemd service type. It should be one of simple, forking, oneshot, dbus, notify, or idle. It defaults to forking. Example:

"scripts": {
    "postinstall": "pixl-boot install --linux_type forking"
}

linux_after

Add --linux_after if you want to specify a service that we must start after. This defaults to network.target, denoting that the server should have basic networking started before trying to start our service. Example:

"scripts": {
    "postinstall": "pixl-boot install --linux_after network.target"
}

linux_wanted_by

Add --linux_wanted_by if you want to customize the WantedBy property in the systemd service file. This defaults to multi-user.target. Example:

"scripts": {
    "postinstall": "pixl-boot install --linux_wanted_by multi-user.target"
}

darwin_type

Add --darwin_type to customize the type of startup service you want on Darwin (OS X) systems. Darwin supports two different types of startup services, LaunchAgents and LaunchDaemons. In short, a LaunchAgent only starts up when a user log in, while a LaunchDaemon starts up earlier, before any user logs in. The default type is LaunchAgent, but beware of changing this to LaunchDaemon, because this may start your service before things like network are available. You only need to add this to the pixl-boot install command. Example:

"scripts": {
    "postinstall": "pixl-boot install --darwin_type LaunchAgent"
}

Sample Shell Control Script

Your module is expected to provide a simple shell (or Node.js) control script, which will start and stop your daemon based on CLI commands. Stopping your daemon from a shell script is usually accomplished by using a PID File. If you do not have one of these scripts handy, we provide a sample one for you:

sample-control.sh

Copy this script to your package directory (typically in a bin subdirectory but doesn't have to be), name it whatever you want, and configure these three lines near the top of the file:

NAME="YOUR_SERVICE_NAME_HERE"
BINARY="node lib/main.js"
PIDFILE="logs/pid.txt"

Set NAME to your service's name (just used for display purposes during startup / shutdown). Set BINARY to the shell command used to actually launch your Node.js daemon (relative to your package base directory). And finally, set PIDFILE to the location of your daemon's PID file.

Your Node.js daemon is expected to fork a daemon (background) process when launched, and write out its own PID file after forking. An easy way to do this is to use the npm daemon package, and then call fs.writeFileSync() for the PID file. Example:

// forks a daemon process and exits main process
require('daemon')();
 
// write PID file after forking
require('fs').writeFileSync( "logs/pid.txt", process.pid );

JavaScript API

In addition to the command-line interface for pixl-boot there is also a JavaScript API you can use in your Node.js code, to install and/or uninstall startup services. To use this, first call require('pixl-boot) to load the module, and the returned object exposes install() and uninstall() functions. Both functions accept an options object, and a callback. The options object accepts all the named command-line arguments, sans the hyphens. Example use:

var boot = require('pixl-boot');
var opts = {
    name: "MyService",
    company: "Node",
    script: "bin/control.sh",
    linux_type: "forking",
    linux_after: "network.target",
    linux_wanted_by: "multi-user.target",
    darwin_type: "agent"
};
 
// install startup service
boot.install(opts, function(err) {
    if (err) throw err;
} );
 
// uninstall startup service
boot.uninstall(opts, function(err) {
    if (err) throw err;
} );

Licenses

The MIT License

Copyright (c) 2016 - 2019 Joseph Huckaby.

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.

The sample-control.sh file included with this package is based on one originally written by Marc Slemko, and is licensed under The Apache Software License, Version 1.1.