[Python-Dev] Another threading idea

[Paul Moore]

On 3/14/06, Raymond Hettinger <raymond.hettinger at verizon.net> wrote:
> FWIW, I've been working on a way to simplify the use of queues with daemon
> consumer threads
>
> Sometimes, I launch one or more consumer threads that wait for a task to enter a
> queue and then work on the task. A recurring problem is that I sometimes need to
> know if all of the tasks have been completed so I can exit or do something with
> the result.
[...]
> So, the idea is to create a subclass of Queue that increments a counter when
> objects are enqueued, that provides a method for worker threads to decrement the
> counter when the work is done, and offers a blocking join() method that waits
> until the counter is zero

I've also hit this problem, and would find this pattern useful.

FWIW, in my code, I bypassed the problem by spawning one worker per
task, and waiting on them all. This works, but is sub-optimal (there's
no need for 100+ subthreads, when 20 or so generic workers would have
done...)

Paul.