monex/dist/interactive/controller_cluster.js

Execute one or multiple scripts, interactively or in daemon mode, and restart them whenever they crash or a watched file changes.

/* IMPORT */
import cluster from 'node:cluster';
import os from 'node:os';
import path from 'node:path';
import process from 'node:process';
import { color } from 'specialist';
/* MAIN */
// The cluster controller should be spawned with the right options, and then it will spawn and respawn its workers
if (cluster.isPrimary) { // Controller, just to be sure
    const options = JSON.parse(process.argv[2]);
    const name = options.name;
    const delay = options.delay || 1000;
    const workersSize = Math.max(2, options.size || os.cpus().length);
    const workers = new Set();
    let exiting = false;
    const setup = () => {
        cluster.setupPrimary({
            exec: path.resolve(process.cwd(), options.exec),
            args: options.args,
            windowsHide: true
        });
    };
    const init = () => {
        for (let i = 0; i < workersSize; i++) {
            fork();
        }
    };
    const fork = () => {
        if (exiting)
            return;
        if (workers.size >= workersSize)
            return;
        console.log(`[monex] ${name ? `${color.bold(name)} - ` : ''}Starting cluster worker...`);
        const worker = cluster.fork();
        workers.add(worker);
    };
    const onExit = () => {
        exiting = true;
        for (const worker of workers) {
            if (worker.isDead())
                continue;
            worker.kill('SIGTERM');
        }
    };
    const onWorkerExit = (worker) => {
        workers.delete(worker);
        setTimeout(fork, delay); // Restarting it
    };
    cluster.on('exit', onWorkerExit);
    process.on('SIGTERM', onExit);
    setup();
    init();
}