Is there a way to stop a running process in concurrent.futures?

Question

How can I terminate a running process, started using concurrent.futures? As I understand, the cancel() method is there to remove a process from the queue if it is not running. But what about killing a running process? For example, if I have a long running process, and I want to stop it when I press a Cancel button in a GUI.

Answer 1

In this case it would probably be better to use a multiprocessing.Process for a long running task.

Create a multiprocessing.Event before starting the new process. Have the child process check the status of this Event regularly, and make it exit when Event.is_set() returns True.

In your GUI code, have the callback associated with the button call set() on the Event.

Answer 2

You may want to look at my answer to a related StackOverflow question here.

In short, there does not appear to be a simple way to cancel a running process inside a concurrent.futures.ProcessPoolExecutor. But you can accomplish it in a hacky way by killing the child processes manually.