CODEWITHSUNDEEP
python
Kingname
Kingname

Reputation: 1362

With python multiprocessing how can child process terminate another child process?

I have two child processes created by my main application process.

A = Process(target=a, args=(aaa,))

B = Process(target=b,args=())

For the sake of argument they are called A and B; How could process A terminate Process B?

Upvotes: 1

Views: 295

Answers (1)

Matt Seymour
Matt Seymour

Reputation: 9395

Whilst I would seriously not recommend child processes being able to nuke each other. Personally I would have the main process managing child processes.

If you want to go down the route you are currently on. One way you could do what you wanted would be to get the main process to pass the process id of child A to child B (or how ever you want to do it). Using this the process ID you pass to the process you can then terminate the process.

Option 1: If only one process can terminate the other then the simplest solution is for process B to be started first. Then for process A to be passed process B's process ID. Using this you can the terminate the process.

def a(pid):
    os.kill(pid)

B = Process(target=b, args=())

A = Process(target=a,args=(B.pid))

Option 2: To do this you can use Queues or Pipes (from the multiprocessing library).

from multiprocessing import Process, Queue

def f(q):
     # will send the process id of the alternative child process 
     print q.get()

if __name__ == '__main__':
    queue_A = Queue()
    queue_B = Queue()
    A = Process(target=f, args=(queue_A,))
    B = Process(target=f,args=(queue_B,))
    A.start()
    B.start()

    queue_A.put(B.pid)
    queue_B.put(A.pid)
    # do stuff....

Option 3 (my preferred method): Get the main process to do the terminating.

A = Process(target=a, args=())

B = Process(target=b,args=())

A.terminate()
B.terminate()

Upvotes: 2

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