How to restart a process with NodeJS?

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How to restart a process with NodeJS?

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#1 by (1 votes)
#2 by (0 votes)

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Currently, I'm doing a code to monitor my files in a given directory and see when changes occur, in order to restart the server, the server is express, and it is running from another file, the server has been a sub -process, this is my code:

watcher.js

#!/usr/bin/env node
'use strict';

var fs = require('fs');
var spawn = require('child_process').spawn;

const BASE_DIR = __dirname;
const ENCODING = 'utf8';

var child_server = spawn('node', ['${BASE_DIR}/main.js'], {stdio: [null, null, null, 'ipc']});


child_server.stdout.on('data', (data) => {
    console.log(data.toString(ENCODING));
});

child_server.stderr.on('data', (data) => {
    console.log('Traceback:\n');
    console.log(data.toString(ENCODING));
});

child_server.on('exit', () => {
    // aqui es donde trato volver a iniciar el proceso, pero no inicia
    setTimeout(() => {
        // console.log(child_server);
        child_server = spawn('node', ['${BASE_DIR}/main.js'], {stdio: [null, null, null, 'ipc']});
    }, 2000);
    console.log('Restaring the server...');
});

fs.watch(BASE_DIR, {encoding: 'buffer', recursive: true}, (eventType, filename) => {
    if (eventType == 'change' && filename) {
        // child_server.kill('SIGHUP');
        child_server.kill('SIGINT');
    }
});

process.on('SIGINT', function() {
    console.log("Caught interrupt signal");

    child_server.kill();
    process.exit();
});

process.on('uncaughtException', function(error) {
    child_server.kill();
    throw error;
});

It works almost well, that is, as soon as it is executed, it starts the server successfully, but when detecting the change, it kills the server process but does not restart it.

The question basically is how to properly restart a process with nodejs ?

nodejs proceso

asked by German Alzate 30.12.2016 в 23:28

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2 answers

0

Seeing your code I see that you send a

child_server.kill()

Send a signal to the child process. If no arguments are given, it will send 'SIGTERM' .

Note that even if you invoke the kill function, the signal sent to the child process can not actually end it. In fact, kill only sends a signal to a process.

Try with:

child_server.disconnect()

check your child's PID for sure you're not killing it well and it's not creating you when you restart.

answered by 31.12.2016 в 03:47

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score 1 · Accepted Answer

#!/usr/bin/env node
'use strict';

var fs = require('fs');
var spawn = require('child_process').spawn;

const BASE_DIR = __dirname;
const ENCODING = 'utf8';

var child_server;

start();

function start(){
    child_server = spawn('node', ['${BASE_DIR}/main.js'], {stdio: [null, null, null, 'ipc']});
    child_server.stdout.on('data', (data)=>{out(data)});
    child_server.stderr.on('data', (data)=>{err(data)});
}

function out(data){
    console.log(data.toString(ENCODING));
}

function err(data){
    console.log('Traceback:\n');
    console.log(data.toString(ENCODING));
}

fs.watch(BASE_DIR, {encoding: 'buffer', recursive: true}, (eventType, filename) => {
    if (eventType == 'change' && filename) {
        // child_server.kill('SIGHUP');
        child_server.kill('SIGINT');
        console.log("Reiniciando...");
        //Aqui lo reinicia.
        start();
    }
});

process.on('SIGINT', function() {
    console.log("Caught interrupt signal");

    child_server.kill();
    process.exit();
});

process.on('uncaughtException', function(error) {
    child_server.kill();
    throw error;
});