bookbrainz/bookbrainz-site

/* eslint-disable node/no-process-exit, no-console, no-process-exit */

/**
 * Captures process exits and signals and calls user-defined cleanup function.
 * On SIGINT, terminate straight away instead of running cleanup function
 * Catches uncaught exceptions, and supports asynchronicity in cleanup function
 * @param {function} cleanupPromise - graceful cleanup function to call on exit.
 * If the function returns false, it will be considered an asynchronous function
 * and you will have to run `process.kill(process.pid, errorCode)` yourself.
 */

function cleanupOnExit(cleanupPromise) {
    process.on('asyncExit', () => {
        cleanupPromise().then(() => {
            console.log('Cleanup process finished');
            process.exit(0);
        }).catch((error) => {
            console.log(error);
            process.exit(1);
        });
    });

    function terminateHandler(code) {
        console.log(`${code} signal received, terminating straight away`);
        // eslint-disable-next-line @typescript-eslint/no-use-before-define -- safe, functions hoisted
        removeAllListeners();
        process.kill(process.pid, code);
    }

    function cleanupHandler(code) {
        console.log(`About to exit with code: ${code}`);
        process.emit('asyncExit', code);
        // callback();
        // eslint-disable-next-line @typescript-eslint/no-use-before-define -- safe, functions hoisted
        removeAllListeners();
    }

    function removeAllListeners() {
        // Node <10 does not have process.off
        if (typeof process.off !== 'function') {
            process.removeListener('exit', cleanupHandler);
            process.removeListener('SIGHUP', cleanupHandler);
            process.removeListener('SIGQUIT', cleanupHandler);
            process.removeListener('SIGTERM', terminateHandler);
            process.removeListener('SIGINT', terminateHandler);
        }
        else {
            process.off('exit', cleanupHandler);
            process.off('SIGHUP', cleanupHandler);
            process.off('SIGQUIT', cleanupHandler);
            process.off('SIGTERM', terminateHandler);
            process.off('SIGINT', terminateHandler);
        }
    }

    process.on('exit', cleanupHandler);
    process.on('SIGHUP', cleanupHandler);
    process.on('SIGQUIT', cleanupHandler);

    // catch ctrl+c event and exit normally
    process.on('SIGINT', terminateHandler);
    process.on('SIGTERM', terminateHandler);

    // catch uncaught exceptions, trace, then exit with error (will trigger cleanup)
    process.on('uncaughtException', (error) => {
        console.error('Uncaught Exception:');
        console.error(error.stack);
        process.exit(1);
    });
}

export default cleanupOnExit;