How to use multiprocessing with class instances in Python?

Question

I am trying to create a class than can run a separate process to go do some work that takes a long time, launch a bunch of these from a main module and then wait for them all to

Answer 1

REF: https://stackoverflow.com/a/14179779

Answer on Jan 6 at 6:03 by David Lynch is not factually correct when he says that he was misled by http://www.doughellmann.com/PyMOTW/multiprocessing/communication.html.

The code and examples provided are correct and work as advertised. next_task() is executing a task received via the queue -- try and understand what the Task.__call__() method is doing.

In my case what, tripped me up was syntax errors in my implementation of run(). It seems that the sub-process will not report this and just fails silently -- leaving things stuck in weird loops! Make sure you have some kind of syntax checker running e.g. Flymake/Pyflakes in Emacs.

Debugging via multiprocessing.log_to_stderr()F helped me narrow down the problem.