How do I kill forked child process after use?

Question

I have this function and fork a child process to run a heavy work on background. The work module sends message after it completes the work. How do I kill or close the forked process?

function doWork() {
    var child = cp.fork(__dirname + '/work');
    child.on('message', function(m) {
      console.log('completed: ' + m);
      // try to kill child process when work signals it's done
      child.kill('SIGHUP');
    });
    child.send({
      msg: 'do work',
      name: self.myname
    });
}

-edit-

I tried child.kill('SIGHUP') and child.kill(); when work signals it's done. I seems didn't kill the process. If I do ps | grep node, it still shows the work process is alive. What am I missing?

Answer 1

I hope I'm not too late!

You can try to get pid of the forked child and pass it to child as reference and when job is done send pid along with the completion signal and you can kill the process based on pid.

function doWork() {
    var child = cp.fork(__dirname + '/work');
    child.on('message', function(m) {
        //try to pass pid along with the signal from child to parent
        console.log('completed: ' + m);
        //killing child process when work signals it's done
        process.kill(m.pid);
    });
    child.send({
        msg: 'do work',
        name: self.myname,
        pid : child.pid // passing pid to child
    });
}