Node: Cannot kill child processes.

[ErraticFox]

• Version: 6.2.1
• Platform: Win10 x64
• Subsystem: Child_Processes

Hello, before I explain my problem, let me ask this is a really plain and basic way.
If I have

function submitBtn() {
    var proc = require("child_process"),
    cmd = 'ffmpeg -y -i input.mp4 output.mp3',
    func = proc.exec(cmd, function(err, stdout, stderr) {})
}

Example 1: Let's say that input.mp4 is one minute long. So it runs func, then completes in a very short amount of time and exits the process completely.
Example 2: Let's say that input.mp4 is two hours now. Runs the func, but takes more than a minute to complete. Is there a way to force close the process before it completes? This wouldn't be inside submitBtn as this would be another button, so it'd be inside another function.

I keep getting people saying to use process.on("exit"...) but that only runs after the program is done. I'm at a loss for this and spent around a day and half for this explanation.

[mscdex]

As long as you keep a reference to your child process object (func in your case), you can call func.kill() to kill the process early.

[ErraticFox]

It says it killed it, but ffmpeg.exe stays open in the background (viewable from task manager) and runs until the conversion is complete.

[mscdex]

@ErraticFox Try starting the child process with execFile() or spawn() instead of exec(). The former two do not spawn a shell, which may be what is being killed instead of the actual target process.

[ErraticFox]

Worked perfectly for execFile(). Thanks!

[bnoordhuis]

If you do need a shell, spawn it with { detached: true }. You can then kill the whole process group with process.kill(-child.pid).

Does not work on Windows and your child processes can of course spawn process groups of their own.