Okay, fair. I am guessing that the first step would be to create a quality implementation and publish it on PyPI. And of course this begs the question, *who* is going to do the work? [ducks]
On Mon, Dec 28, 2020 at 10:27 AM Roger Iyengar <raiye...@cs.cmu.edu> wrote: > It was not sufficient. The only way to communicate with a Subprocesses is > using stdout, stdin and stderr. However, packages like Tensroflow will > print messages to stdout, and this can be hard to turn off. > > It seems useful to have a class like multiprocessing.Pipe to communicate > with another process, separately from stdout/stdin. > > On Mon, Dec 28, 2020 at 12:50 PM Guido van Rossum <gu...@python.org> > wrote: > >> The asyncio module already has a subprocess support: Subprocesses — >> Python 3.9.1 documentation >> <https://docs.python.org/3/library/asyncio-subprocess.html> >> >> Was that not sufficient to solve your problem? >> >> >> On Mon, Dec 28, 2020 at 5:23 AM Roger Iyengar <raiye...@cs.cmu.edu> >> wrote: >> >>> I believe that asyncio should have a way to wait for input from a >>> different process without blocking the event loop. >>> >>> The Asyncio module currently contains a Queue class that allows >>> communication between multiple coroutines running on the same event loop. >>> However, this module is not threadsafe or process-safe. >>> >>> The multiprocessing module contains Queue and Pipe classes that allow >>> inter-process communication, but there's no way to directly read from these >>> objects without blocking the event loop. >>> >>> I propose adding a Pipe class to asyncio, that is process-safe and can >>> be read from without blocking the event loop. This was discussed a bit >>> here: >>> https://github.com/python/cpython/pull/20882#issuecomment-683463367 >>> >>> This could be implemented using the multiprocessing.Pipe >>> class. multiprocessing.connection.Connection.fileno() returns the file >>> descriptor used by a pipe. We could then use loop.add_reader() to set >>> an asyncio.Event when something has been written to the pipe by the other >>> process. I did this all manually in a project I was working on. However, >>> this required me to learn a considerable amount about asyncio. It would >>> have saved me a lot of time if there was an easy documented way to wait for >>> input from another process in a non-blocking way. >>> >>> One compelling use case for this is a server that uses asyncio, which >>> receives inputs from clients, then sends these to another process that runs >>> a neural network. The server then sends the client a result after the >>> neural network finishes. ProcessPoolExecutor does not seem like a good fit >>> for this use case, because the process needs to stay alive and be re-used >>> for subsequent requests. Starting a new process for each request is >>> impractical, because loading the neural network into GPU memory is an >>> expensive operation. See here for an example of such a server (however this >>> one is mostly written in C++ and does not asyncio): >>> https://www.tensorflow.org/tfx/guide/serving >>> _______________________________________________ >>> Python-ideas mailing list -- python-ideas@python.org >>> To unsubscribe send an email to python-ideas-le...@python.org >>> https://mail.python.org/mailman3/lists/python-ideas.python.org/ >>> Message archived at >>> https://mail.python.org/archives/list/python-ideas@python.org/message/2YTRR3QUFJ66MOJKVUQXAVPBY4AKB4PX/ >>> Code of Conduct: http://python.org/psf/codeofconduct/ >>> >> >> >> -- >> --Guido van Rossum (python.org/~guido) >> *Pronouns: he/him **(why is my pronoun here?)* >> <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/> >> > -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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