iterqueue

A Python Queue subclass that consumers can use as an iterator.

Introduction

The Iterqueue class is a subclass that allows threaded consumers from a Python Queue-like object to use it like a iterator, for example with a for loop. This requries the concept of an end to the queue, and that requires some change on the producer side of a queue.

The change in this module is to require that producers use the Queue as a context (using with), and consumers can use it via a for statement. A trivial example:

import iterqueue

# create a Queue, and add something to it
target = iterqueue.Iterqueue()
with target:  # this is required, without it the consumer will hang
  target.put(1)

# read out the contents
for item in target:
  print(item)

# here all items have been processed

Normally producers and consumers should each be in their own thread, and this class supports multiple simultanious producers and consumers. The consumers can just use it in a for loop, while the producers should use it via a with statement and when the producers are complete (drop through the with statement), and the queue is exausted the consumers will stop (via a StopIteration). Canceling in the middle (from consumers, producers, or otherwise) is also supported.