index.js

const express = require("express");
const app = express();
const port = process.env.PORT || 3000;

const path = require("path");
const bodyParser = require("body-parser");
const cors = require("cors");
const cluster = require("cluster");
const cCPUs = require("os").cpus().length;
const db = require("./models");


const router = require("./routers/index");
const createError = require("http-errors");


// Middleware

app.use(express.static(path.join(__dirname, "public/static")));
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use(cors());
app.use(express.json());
db.sequelize.sync();
app.use("/api/v1", router);

if (cluster.isMaster) {
    for (var i = 0; i < cCPUs; i++) {
        cluster.fork();
    }

    cluster.on('online', function (worker) {
        console.log('Worker ' + worker.process.pid + ' is online.');
    });
    cluster.on('exit', function (worker, code, signal) {
        console.log('worker ' + worker.process.pid + ' died.');
    });
}
else {

    // Routing


    app.use(async (req, res, next) => {
        next(createError(404, "Not Found"));
    });

    app.use((err, req, res, next) => {
        res.status(err.status || 500);
        res.send({
            status: false,
            error: {
                status: err.status || 500,
                message:
                    process.env.MODE === "development" ? err.message : "Error Occoured",
            },
        });
    });

    // Listen
    app.listen(port, () => {
        console.log(`Server is listening on PORT No. ${port}`);
    });
}