respawn's Introduction

respawn

Spawn a process and restart it if it crashes.

npm install respawn

Usage

It is easy to use

var respawn = require('respawn');

var monitor = respawn(['node', 'server.js'], {
	env: {ENV_VAR:'test'}, // set env vars
	cwd: '.',              // set cwd
	maxRestarts:10,        // how many restarts are allowed within 60s
	sleep:1000,            // time to sleep between restarts
});

monitor.start(); // spawn and watch

Optionally you can specify the command to to spawn in the option map as command: [...]

API

monitor.start() Starts the monitor
monitor.stop(cb) Stops the monitor (kills the process if its running with SIGTERM)
monitor.status Get the current monitor status. Available values are running, stopping, stopped and sleeping

Events

monitor.on('start') The monitor has started
monitor.on('stop') The monitor has fully stopped and the process is killed
monitor.on('sleep') monitor is sleeping
monitor.on('spawn', process) New child process has been spawned
monitor.on('exit', code, signal) child process has exited
monitor.on('stdout', data) child process stdout has emitted data
monitor.on('stderr', data) child process stderr has emitted data
monitor.on('warn', err) child process has emitted an error

Graceful restart

To do graceful restart simply have your app stop gracefully when receiving SIGTERM and do

// graceful restart (do not wait for old process to die)
monitor.stop();
monitor.start();

// hard restart (wait for old process to die)
monitor.stop(function() {
	monitor.start();
});