@mangar2/shutdown/shutdown.js

Implements graceful shutdown

/**
 * @license
 * This software is licensed under the GNU LESSER GENERAL PUBLIC LICENSE Version 3. It is furnished
 * "as is", without any support, and with no warranty, express or implied, as to its usefulness for
 * any purpose.
 *
 * @author Volker Böhm
 * @copyright Copyright (c) 2020 Volker Böhm
 * @name Shutdown
 * @description
 * Shutdown is a small helper to safely shutdown serivces on SIGINT (ctrl-C)
 * A singelton calling a callback on SIGINT and provides a timeout if the callback does not finish in a period of time.
 * @example
 * const shutdown = require('shutdown');
 *
 * shutdown(async () => {
 *    await myClass.close();
 *    process.exit(0);
 * });
 */

'use strict'

const FORCE_SHUTDOWN_TIMEOUT_IN_MILLISECONDS = 4000

var sigintCallback
var timeout

/**
 * @param {function} callback function called on sigint before shutdown
 * @param {number} [forceShutdownTimeoutInMilliseconds=FORCE_SHUTDOWN_TIMEOUT_IN_MILLISECONDS]
 * amount of milliseconds until shutdown is forced
 */
module.exports = (callback, forceShutdownTimeoutInMilliseconds) => {
    timeout = forceShutdownTimeoutInMilliseconds
    if (isNaN(timeout)) {
        timeout = FORCE_SHUTDOWN_TIMEOUT_IN_MILLISECONDS
    }
    sigintCallback = callback

    process.on('SIGINT', () => {
        if (sigintCallback !== undefined) {
            sigintCallback()
        }

        setTimeout((err) => {
            if (err) {
                console.error(err)
            }
            process.exit(1)
        }, timeout)
    })

    process.on('SIGTERM', () => {
        process.exit(0)
    })
}