Replace multiprocessing.Queue with Manager.Queue

[xin-huang]

In a separate project, I experienced deadlocks when using multiprocessing.Queue.

I found a solution by switching to Manager.Queue, as recommended in the Python documentation:

Warning

As mentioned above, if a child process has put items on a queue (and it has not used JoinableQueue.cancel_join_thread), then that process will not terminate until all buffered items have been flushed to the pipe.

This means that if you try joining that process you may get a deadlock unless you are sure that all items which have been put on the queue have been consumed. Similarly, if the child process is non-daemonic then the parent process may hang on exit when it tries to join all its non-daemonic children.

Note that a queue created using a manager does not have this issue. See Programming guidelines.

Although I have not encountered deadlocks in dadi-cli, I suggest switching from multiprocessing.Queue to Manager.Queue to avoid potential deadlock issues.

dadi-cli/dadi_cli/__main__.py

Line 344 in 708667f

from multiprocessing import Process, Queue