Resilient NodeJS Server

index.js

import * as os from "os"
import * as cluster from "cluster"
import { bootstrap } from "./server"
const numCpus = os.cpus().length

const handleFork = () => {
    const worker = cluster.fork()
    worker.addListener("exit", (code) => {
        if (code !== 0) handleFork()
    })
}

const main = () => {
    for (let i = 0; i < numCpus; i++) handleFork()
}

const worker = () => bootstrap()

cluster.isMaster ? main() : worker();

server.js

'use strict'

import * as http from "http"
const PORT = process.env.PORT || 1337

export const bootstrap = () => {

    const server = http.createServer((req, res) => {
        res.writeHead(200, { "Content-Type": "text/json" })
        return res.end(JSON.stringify({ message: "Hello World" }))
    })

    server.listen(PORT)
    server.once("listening", () => {
        console.log(`server starting on ${PORT} with process id ${process.pid}`)
    })

    process.on('SIGINT', () => {
        console.log(`${process.pid} server process ending`, new Date().toISOString())
        server.close(() => process.exit())
    })

    process.on('SIGTERM', () => {
        console.log(`${process.pid} server process ending`, new Date().toISOString())
        server.close(() => process.exit())
    })

    process.on('uncaughtException', (error) => {
        console.error(`unhandledRejection happened: ${error.stack || error}`)
    })

    process.on('unhandledRejection', (error) => {
        console.error(`unhandledRejection happened: ${error.stack || error}`)
    })
    
}