yogi

yogi posted

how to make process run in background in Node JS ?

i have some process to run in background when people is playing with Node JS Electron Application .

so main thread remain untouched , and background process do their job without any leg to main screen.

i want to download some server data to process so local application remain up to date . but json data should be downloaded in the background process so main application remain undisturbed so is it possible to run multi threading in Node JS programmed application

it should be multi threading in Node JS or multi processing in node.js . so it can share the load of application

to scale up the applications by splitting a single thread into multiple thread , is that possible in Node JS
Mitul Dabhi

Mitul Dabhi
answered Dec 13 '17 20:17

first of all multi threading is not possible with Node JS because Node.js runs in a single thread.
but you can create multiple workers for a parent process
it is possible with cluster module in Node JS .


const cluster = require('cluster');


Worker communicate with process via IPC

const electron = require('electron')
const cluster = require('cluster');
const numCPUs = require('os').cpus().length
const app = electron.app
// Module to create native browser window.
const BrowserWindow = electron.BrowserWindow

const path = require('path')
const url = require('url')

if (cluster.isMaster) {
  console.log(`Master ${process.pid} is running`);

  // Fork workers.
  for (let i = 0; i < numCPUs; i++) {
    cluster.fork();
  }

  cluster.on('exit', (worker, code, signal) => {
    console.log(`worker ${worker.process.pid} died`);
  });
} else {
// Module to control application life.


// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindow

function createWindow () {
  // Create the browser window.
  mainWindow = new BrowserWindow({width: 800, height: 600})

  // and load the index.html of the app.
  mainWindow.loadURL(url.format({
    pathname: path.join(__dirname, 'index.html'),
    protocol: 'file:',
    slashes: true
  }))

  // Open the DevTools.
  // mainWindow.webContents.openDevTools()

  // Emitted when the window is closed.
  mainWindow.on('closed', function () {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null
  })
}
// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.

app.on('ready', createWindow)

// Quit when all windows are closed.

app.on('window-all-closed', function () {
  // On OS X it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', function () {
  // On OS X it's common to re-create a window in the app when the
  // dock icon is clicked and there are no other windows open.
  if (mainWindow === null) {
    createWindow()
  }
})
}
// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.


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shyam

shyam
answered Dec 13 '17 20:17

simply install forever package

[sudo] npm install forever


A simple CLI tool for ensuring that a given script runs continuously


 forever start server.js

start forever server.js file


 forever list

list command will list all forever call with process id
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