graceful-hook v1.0.3

graceful-hook

This module is somewhat a merge of Exit-Hook and Signal-Exit.

This is because exit-hook does not cover all exit signals although with a little editing, I found that it better handles multiple hooks and waiting for asynchronous processes to end, something that signal-exit wasn't very good at.

Moreover, exit-hook wonderfully handles pm2 exits.

This module is thus the best of both worlds.

Here are some of the things it does differently:

• Returns the signal to callback function unlike exit-hook
• Tries to handle async callbacks, including waiting for them to resolve
• Includes all the signals that are handled by signal-exit and not exit-hook
• Handles pm2 shutdown messages as handled by exit-hook and not signal-exit
• Adds an ignore option to ensure certain signals can be ignored. This fine grained signal handling is important to ensure the hook plays well with tools like Nodemon.

Install

$ npm install graceful-hook

Usage

const gracefulHook = require('graceful-hook');

// Hook with option to ignore some signals
gracefulHook(async (signal, signalNum) => {
	console.log(`${signal} received`);
	console.log('Exiting with after some async process...');

    await longAsyncProcess();

}, {ignore:['SIGUSR2']});

// You can add multiple hooks, even across files
gracefulHook(() => {
	console.log('Exiting 2');
});

throw new Error('🦄');

API

gracefulHook(callbackFn, [options]);

Options

• ignore : Array of signals to ignore.

  	This is important when using tools like [Nodemon](https://www.npmjs.com/package/nodemon) that will restart the process on change, not because the process is actually exiting. Nodemon for example will exit with the signal *'SIGUSR2'* so you can ignore that.