How to restart node app from iteself?

[ronovar]

I need when i call api for /restart to restart application.js i try using this code:

child_process.exec(['killall -9 node && node --expose-gc /root/application.js'], 
                   function (error, stdout, stderr) { }
):

But the problem is that node is killed but application.js is not run and application is not running.

I read that i need to use spawn not child_process.exec but i im unable to make it work...so can you please post me above code of using spawn?

I im using node version: v7.10.1
ubuntu server x64 14.04 LTS

I need to kill node (application.js) and run it again...so short say restart application.js

Thanks

[Knighton910]

Have you tried nodemon: https://nodemon.io/

[ronovar]

I need to restart it internaly from itself...i have app with buttons restart stop and shutdown...so when user click stop if i use nodemon it will restart not kill app....so do you have idea how can i use to restart internally using javascript code?

[MM422]

Hi, I am not quite sure whether I have fully understand about your use case but could you try this: https://github.com/foreverjs/forever

[ORESoftware]

Best thing to do is to launch a process which launches your app as a child process. The parent process can kill and restart the child process at will. I wrote a simple nodemon alternative, the source is here:

https://medium.com/@the1mills/diy-nodemon-5176fdcc1cfb

[ronovar]

Thanks ORESoftware...but i have node application that check if node isMaster process and i need to restart master process not child process..because i do node process clustering and i im using node clustering to do heavy stuff there so master process is what i need to restart using console...i read that best aproach is using terminal command like above but not using child process and using spawn but i try few spawn commands but none works

[gireeshpunathil]

@ronovar - is this still outstanding?

[gireeshpunathil]

closing due to inactivity, please re-open if it is still outstanding.

[rockyjvec]

I thought I'd share how I did this in hopes it might help someone else searching how to do the same thing. This issue was the first result on google when I was searching for how to do this.

I'm using rabbitmq to manage scalable puppeteer worker processes for PDF generation of HTML pages. I'm using a rabbitmq exchange to send messages to all the workers to restart or shutdown themselves. Here is the relevant code I am using to have the worker processes restart themselves:

const {spawn} = require('child_process');

if(action === 'restart')
{
    console.log("restarting...");

    const logfile = 'path_to_the_log_file.log';
    const out = fs.openSync(logfile, 'a');
    const err = fs.openSync(logfile, 'a');
    const subprocess = spawn(process.argv[1], process.argv.slice(2), {detached: true, stdio: ['ignore', out, err]});

    subprocess.unref();
}
else
{
    console.log("shutting down...");
}
process.exit();

Depending on how you originally start the process, you may need to change argv[1] and slice(2) to argv[0] and slice(1).

Hope that helps.

[twome]

Single-statement version of @rockyjvec's incredibly useful answer:

const restartProcess = () => {
  spawn(process.argv[1], process.argv.slice(2), {
    detached: true, 
    stdio: ['ignore', out, err]
  }).unref()
  process.exit()
}

[ChiweenieDijon]

Just an FYI in case others seeking possible solutions come across this thread, here's a potentially useful mechanism:
If you are running under a process manager w/ auto-restart, (e.g. PM2),
You can send yourself a sigint, or sigterm:

process.kill(process.pid, 'SIGINT')
or
process.kill(process.pid, 'SIGTERM')

(although i think it's not as simple on windows)

[LingleDev]

If you're using pm2, you could simply run this bit of code to restart your process:

var { exec } = require('child_process')

exec("pm2 restart <yourprocessname>")

[true-goniss]

Solution for windows (none of the posted solutions worked):

create restart_script.bat at the same folder as the script with the following content (replace the name):

node script.js
pause

then you can restart the script from itself:

const wait = async(ms) => { return new Promise(resolve => setTimeout(resolve, ms)); }
const { spawn } = require('child_process');
 
const bat = spawn('restart_script.bat', [], {
shell: true,
stdio: 'inherit' 
});

await wait(500);
process.exit(1);