@darkobits/adeiu

Yet another POSIX signal handler.

Features

• Ensures provided functions are called before any other event listeners and are run concurrently, minimizing shutdown time.
• Works with any combination of synchronous and asynchronous functions.
• Ensures a clean exit if all functions resolve/return.
• Exits with an error if any functions reject/throw.
• Ensures processes exit cleanly, even when they have asynchronous shut-down functions and the Node debugger is in use. (See this issue)

Install

npm i @darkobits/adeiu

Use

Adeiu accepts an asynchronous or synchronous handler function and returns a function that can be invoked to unregister the handler. By default, the handler will be registered to respond to the following signals:

• SIGINT
• SIGQUIT
• SIGTERM
• SIGUSR2

import adeiu from '@darkobits/adeiu';

// Register a callback.
const annuler = adeiu(async signal => {
  console.log(`Hey, we got ${signal}. Exiting...`);

  await someAsyncStuff();

  console.log('All done!');
});

// Un-register the callback.
annuler();

Customizing Signals

Usually, responding to signals dynamically can be accomplished by inspecting the signal argument passed to your callback. However, if it is important that listeners are only installed on a particular signal, you may optionally provide a custom array of signals to assign a callback to.

import adeiu from '@darkobits/adeiu';

// Register callback that will _only_ be invoked on SIGINT.
adeiu(() => {
  // SIGINT cleanup tasks.
}, ['SIGINT']);

import adeiu, { SIGNALS } from '@darkobits/adeiu';

// Register callback with the default signals and SIGUSR1.
adeiu(() => {
  // Custom cleanup tasks.
}, [...SIGNALS, 'SIGUSR1']);