Add ability to kill subprocess when parent process exits

[josegonzalez]

The cmd object is not exposed in any way, so there is no way to call cmd.Process.Kill() out of band if the parent process exits early.

Expected Behaviour

I expect to be able to kill the process, or at least have it automatically exit on it's own with a non-zero exit code.

Current Behaviour

The process is currently orphaned and continues running to completion.

Possible Solution

Not sure, maybe an option like ListenToSignals (default false) that will listen to process signals and pass them along to the child. This would allow ctrl+c and the like to work properly (not sure about SIGKILL though).

Steps to Reproduce (for bugs)

Use the following in a bin and issue a ctrl+c on the executing terminal. docker ps should still show the container.

package main

import (
	"fmt"

	execute "github.com/alexellis/go-execute/pkg/v1"
)

func main() {
	cmd := execute.ExecTask{
		Args: []string{
			"container",
			"run",
			"--rm",
			"ubuntu",
			"/bin/bash",
			"-c",
			"sleep infinity",
		},
		Command: "docker",
	}

	res, err := cmd.Execute()
	if err != nil {
		fmt.Printf("error executing command: %s", err.Error())
	}

	if res.ExitCode != 0 {
		fmt.Printf("error executing command: %s", res.Stderr)
	}
}

Why do you need this?

I'm writing a tool that wraps docker calls - well, maybe now using the docker api if it seems straightforward enough - and was waiting a long time for a command to execute anything (because the underlying tool was slow). I ran ctrl+c and then noticed the container was still up.

Your Environment

• go version : go version go1.17.9 darwin/amd64

• Operating System and version (e.g. Linux, Windows, MacOS): macOS Monterey 12.3.1

• Link to your project or a code example to reproduce issue: The above code reproduces my issue (the project I'm working on isn't published yet).

[derek]

Please complete the whole issue template, without deleting any headings.

[josegonzalez]

Yeah this bot is wrong, I definitely filled out the entire ticket. I've updated Context to say Why do you need this? based on https://raw.githubusercontent.com/openfaas/faas/master/.DEREK.yml

[josegonzalez]

May be worth looking into Github Forms. Example here (click any of the Get Started links).

[alexellis]

Thanks for the interest @josegonzalez and you're right, Derek is misconfigured on this repo and I've removed that label, however the so called "legacy" templates are required for reasons.

Are you handling signals when the process quits? Like here

Killing your container's PID1 should also kill any other child processes.

Adding a context to the command's execution may allow for it be cancelled later.

Alex

[josegonzalez]

Not sure how I'd handle signals when we don't have direct access to the underlying cmd, but your MR might work for my use case :)