[Python-ideas] @run_as_thread decorator

Guido van Rossum guido at python.org
Sun Mar 6 04:31:51 CET 2011

On Sat, Mar 5, 2011 at 7:25 PM, Jesse Noller <jnoller at gmail.com> wrote:
> On Sat, Mar 5, 2011 at 7:55 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
>> On Sun, Mar 6, 2011 at 3:16 AM, Jesse Noller <jnoller at gmail.com> wrote:
>>> I've long wanted to put something into the stdlib like this, but as
>>> others in the thread have pointed out - there's some semantics that
>>> remain to be hashed out and the behavior is dangerous (imo), and
>>> magical to have in the stdlib right now.
>>> In this case, I would recommend building out a library that contains
>>> these decorators (both threads and processes) building from the
>>> futures (concurrent.futures.Executor ABC) library as possible, and
>>> let's see how it pans out. I've struggled with really liking/wanting
>>> this and the fact that it's dangerous, and surprising.
>> Well said, especially the last line :)
>> However, I suspect this is one of those things where:
>> - rewriting it yourself is easier than finding a library for it, so a
>> PyPI module would gather little interest or feedback
>> - doing it "right" in the stdlib would eliminate the temptation to
>> develop custom not-quite-right implementations (e.g. ones where the
>> decorator actually *creates* and starts the thread)
>> It would make a good topic for a PEP, IMO.
>> Cheers,
>> Nick.
> Well, why stop at one-function in a thread - why not have:
> @threading.pool(10):
> def func(me):
>    .... runs func in a threadpool of 10
> Or
> with threading.pool(10) as pool:
>    pool.in.put(blah)
>    pool.out.get(blah)
> And so on - I can totally buy that it's pep fodder to do it "right"
> once, for the stdlib, I've just struggled and debated with a lot of
> people about how helpful this really is and the right way of doing it.
> The original proposal seems OK at first - just run this function in a
> thread - at first glance it seems like it's a harmless decorator to
> throw a function into a thread or process. But then what about the
> "surprise" that a function call forked a new thread - or new process?
> Maybe you're right - maybe this is good PEP territory. If nothing more
> we could all hash out the various way of biting yourself in the butt
> with these :)

I'm thinking that since all of this is all pretty simple it's
something that applications or 3rd party libraries can easily have in
a "utilities" module of their own. The bar is a lot lower that way.

> jesse
> ps: i love controlling thread/process pools with context managers. I'm ill.

Sick, you mean. :-)

--Guido van Rossum (python.org/~guido)

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