python multiprocessing.Process.terminate - How to kill child processes

Question

This code:

import multiprocessing as mp
from threading import Thread
import subprocess
import time

class WorkerProcess(mp.Process):
  def run(self):
      # Simulate long running task
      self.subprocess = subprocess.Popen(['python', '-c', 'import time; time.sleep(1000)'])
      self.code = self.subprocess.wait()


class ControlThread(Thread):
  def run():
      jobs = []
      for _ in range(2):
          job = WorkerProcess()
          jobs.append(job)
          job.start()

      # wait for a while and then kill jobs
      time.sleep(2)
      for job in jobs:
          job.terminate()

if __name__ == "__main__":
    controller = ControlThread()
    controller.start()

When I terminate the spawned WorkerProcess instances. They die just fine, however the subprocesses python -c 'import time; time.sleep(1000) runs until completition. This is well documented in the official docs, but how do I kill the child processes of a killed process?

A possbile soultion might be:

• Wrap WorkerProcess.run() method inside try/except block catching SIGTERM, and terminating the subprocess.call call. But I am not sure how to catch the SIGTERM in the WorkerProcess

• I also tried setting signal.signal(signal.SIGINT, handler) in the WorkerProcess, but I am getting ValuError, because it is allowed to be set only in the main thread.

What do I do now?

Solution

EDIT: As @svalorzen pointed out in comments this doesn't really work since the reference to self.subprocess is lost.

---

Finally came to a clean, acceptable solution. Since mp.Process.terminate is a method, we can override it.

class WorkerProcess(mp.Process):
    def run(self):
        # Simulate long running task
        self.subprocess = subprocess.Popen(['python', '-c', 'import time; time.sleep(1000)'])
        self.code = self.subprocess.wait()

    # HERE
    def terminate(self):
      self.subprocess.terminate()
      super(WorkerProcess, self).terminate()