Is there any way to pass a process object between multiple processes in python?

Question

I have two files in the same directory, A module has a function that is continously running and has no way to stop or pause in between,

# script.py
def run():
    i = 0
    while True:
        print('\r', i, '\r', end='')
        i += 1

Then there is a custom made debugger module which captures if the directory has been updated,

# debugger.py
import os
import wait
from multiprocessing import Process, Queue

def capture_change(processesQueue):
    prev = os.path.getsize('wait.py')
    while True:
        curr = os.path.getsize('wait.py')

        if curr != prev:
            print('Changes Detected!!')
            process = processesQueue.get()
            process.kill()
            process.start()
            processesQueue.put(process)
        
        prev = curr

if __name__ == "__main__":
    processesQueue = Queue()
    p1 = Process(target= wait.run)
    processesQueue.put(p1)
    p2 = Process(target= capture_change, args= (processesQueue, ))

    p1.start()
    p2.start()

I am getting this error,

    raise TypeError(
TypeError: Pickling an AuthenticationString object is disallowed for security reasons

What should I do? I have searched alot but all the ways for data sharing among other processes are not allowing Process instance itself to be shared among them. Is there any other way around??

The choice to block process objects from being pickled was a conscious decision to avoid security vulnerabilities. Cleanup of the child processes should be happening in the parent process which created it. Why not have `capture_change` be called in the parent process? — flakes, Jun 15 '22 at 22:05

score 0 · Answer 1 · answered Jun 16 '22 at 13:31

Thanks to @flakes I have finally got a way around the part I was hoping to achieve,

# debugger.py
import os
from multiprocessing import Process


def capture_change(processesQueue):
    prev = os.path.getsize('wait.py')
    import wait
    process = Process(target= wait.run)
    process.start()
    while True:
        curr = os.path.getsize('wait.py')

        if curr != prev:
            import wait
            print('Changes Detected!!')
            if process.is_alive():
                process.kill()
            process = Process(target= wait.run)
            process.start()
        
        prev = curr

if __name__ == "__main__":
    capture_change_and_reload()

This is my final code that works as required.

Is there any way to pass a process object between multiple processes in python?

1 Answers1