Daemonize & keep alive

daemon.js

const child_process = require('child_process');

const daemon = (pathname) => {
    const child = child_process.fork(pathname);
    child.unref();
    return child;
};

module.exports = daemon;

keepalive.js

const cluster = require('cluster');
const _ = require('lodash');

const keepalive = async (cb) => {
    if (cluster.isMaster) {
        cluster.fork();

        cluster.on('exit', () => {
            cluster.fork();
        });
    }

    if (cluster.isWorker && _.isFunction(cb)) {
        await cb();
    }
};

module.exports = keepalive;

test.daemon.js

const daemon = require('./daemon');
const path = require('path');

const child = daemon(path.resolve(__dirname, './test.service.js'));
console.log(child.pid);
process.exit();

test.service.js

const keepalive = require('./keepalive');
const fs = require('fs');
const path = require('path');

keepalive(async () => {
    const logFilePathname = path.resolve(__dirname, './info.log');
    fs.appendFileSync(logFilePathname, 'new process\n', { encoding: 'utf-8' });
    for (let i = 0; i < 10; i += 1) {
        fs.appendFileSync(logFilePathname, new Date().toISOString() + '\n', { encoding: 'utf-8' });
        await new Promise((resolve) => setTimeout(() => resolve(), 500));
    }
    process.exit(1);
});