Exiting a multiprocessed python application safely

Question

When we use-  os._exit(<num>) ::

Exit the process with status n, without calling cleanup handlers, flushing stdio buffers, etc.

and that sys.exit() ::

“only” raises an exception, it will only exit the process when called from the main thread

Now, how do I close a multi-processed application that will ensure all processes are closed (none left orphaned) and that it exits in the best state possible?

Also, I am creating the processes using the python multiprocessing library, by creating classes which inherit from multiprocessing Process.

Answer 1

I ended up creating a Pipe for every Process. Then when the main Process shuts down it can send a message to all the children Processes that they should shut down too.

In order to make that work right you've got to put a periodic check into the children Processes' "do loop" to see if there are messages in the pipe, and if so, check them to see if it's a "quit now" message.