balaur

Balaur

Balaur is a daemonizing manager for Node.js applications written in order to be able to create systemctl services for *nix systems. It allows you to run the applications as services (daemons) on *nix systems, with all the features attached to that (start, stop, restart and status).

Installing Balaur

Globally

npm install -g balaur

Locally

npm install balaur

Configuration

Create a file in your project named balaur.config.mjs

Alternatively you can export an environment variable called BALAUR_CONFIG_FILE with the path.

In this file you can specify the following values:

export default {
  main: "index.mjs",
  workers: 1,
  pidfilePath: "pidfile.pid",
  stdOutPath: "out.log",
  stdErrPath: "err.log"
}

• main - default index.mjs - represents the file that exports the default function that will be daemonized
• workers - default 1 on NODE_ENV === development and cpu count on other values - the number of spawned processes (see threads vs process Node.js and C10K problem)
• pidfilePath - default pidfile.pid - the file which maintains the pid of the master process
• stdOutPath - default out.log - the file (or socket) where the stdout will be redirected
• stdErrPath - default err.log - the file (or socket) where the stderr will be redirected

Commands

• start starts a daemon and detaches it creating an IPC Channel for its stderr and stdout
• stop stops the daemon by sending a unix signal, can only be used on started daemons
• restart restarts the daemon by sending a unix signal, can only be used on started daemons

All daemons respect unix signals.

Usage

Execute remote with NPX

npx balaur [command]

Bin

balaur [command]

Custom execution

NOTE: On custom execution the config file does not apply.

Create a index.mjs file with the code similar to the following:

import Balaur from 'balaur';

const config = {
  workers: process.env.NODE_ENV !== 'development' ? cpus().length : 1,
  pidfilePath: 'pidfile.pid',
  stdOutPath: 'out.log',
  stdErrPath: 'err.log'
};

const balaur = new Balaur(() => {
  // Your daemonized code goes here
  console.log('Hello, World!');
}, config);

balaur.processArgs();

systemctl service creation

In your project edit the package.json and modify the following scripts:

{
  "scripts": {
    "start": "balaur start",
    "stop": "balaur stop",
    "restart": "balaur restart"
  }
}

If you used custom execution

{
  "scripts": {
    "start": "node ./ start",
    "stop": "node ./ stop",
    "restart": "node ./ restart"
  }
}

Config the service

Create a user to run your service. This is important to protect your system in case the service can be hacked.

sudo adduser \
   --system \
   --shell /bin/bash \
   --gecos 'node' \
   --disabled-password \
   --home /srv/www \
   node

Create a file in /lib/systemd/system/myservice.service where myservice is the name of your service

Paste the following inside:

[Unit]
Description=My Service
After=network-online.target
Wants=network-online.target

[Service]
User=node
Group=nogroup
WorkingDirectory=/srv/www/path/to/your/project
Type=forking
ExecStart=/usr/bin/npm start
ExecStop=/usr/bin/npm stop
LimitCPU=infinity


[Install]
WantedBy=multi-user.target

Reload the daemons

sudo systemctl daemon-reload

Start/stop/restart daemons

sudo service myservice [start | stop | restart | status]

or

sudo systemctl [start | stop | restart | status] myservice

Enable auto-running on system restart

sudo systemctl enable myservice

Disable auto-running on system restart

sudo systemctl disable myservice