cluster.js

"use strict";

const 
	cluster = require("cluster"),
	stopSignals = [
		"SIGHUP", "SIGINT", "SIGQUIT", "SIGILL", "SIGTRAP", "SIGABRT",
		"SIGBUS", "SIGFPE", "SIGUSR1", "SIGSEGV", "SIGUSR2", "SIGTERM"
	],
	production = process.env.NODE_ENV == "production";

let stopping = false;

cluster.on("disconnect", function(worker) {
	if (production) {
		if (!stopping)
			cluster.fork();
	} else
		process.exit(1);
});

if (cluster.isMaster) {
	const workerCount = process.env.NODE_CLUSTER_WORKERS || 4;
	console.log(`Starting ${workerCount} workers...`);
	for (let i = 0; i < workerCount; i++)
		cluster.fork();

	if (production) {
		stopSignals.forEach(function (signal) {
			process.on(signal, function () {
				console.log(`Got ${signal}, stopping workers...`);
				stopping = true;
				cluster.disconnect(function () {
					console.log("All workers stopped, exiting.");
					process.exit(0);
				});
			});
		});
	}
} else
	require("./server/index.js");