“select” on multiple Python multiprocessing Queues?

Question

What\'s the best way to wait (without spinning) until something is available in either one of two (multiprocessing) Queues, where both reside on the same system?

Answer 1

You could use something like the Observer pattern, wherein Queue subscribers are notified of state changes.

In this case, you could have your worker thread designated as a listener on each queue, and whenever it receives a ready signal, it can work on the new item, otherwise sleep.

Answer 2

As of Python 3.3 you can use multiprocessing.connection.wait to wait on multiple Queue._reader objects at once.