[Python-Dev] PEP 567 v3 (original) (raw)

Yury Selivanov yselivanov.ml at gmail.com
Tue Jan 16 20:06:41 EST 2018

On Tue, Jan 16, 2018 at 7:45 PM, Guido van Rossum <guido at python.org> wrote:

On Tue, Jan 16, 2018 at 4:37 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:

On Tue, 16 Jan 2018 17:44:14 -0500 Yury Selivanov <yselivanov.ml at gmail.com> wrote: > Offloading execution to other threads > ------------------------------------- > > It is possible to run code in a separate OS thread using a copy > of the current thread context:: > > executor = ThreadPoolExecutor() > currentcontext = contextvars.copycontext() > > executor.submit( > lambda: currentcontext.run(somefunction)) Does it also support offloading to a separate process (using ProcessPoolExecutor in the example above)? This would require the Context to support pickling. I don't think that's a requirement. The transparency between the two different types of executor is mostly misleading anyway -- it's like the old RPC transparency problem, which was never solved IIRC. There are just too many things you need to be aware of before you can successfully offload something to a different process.

I agree.

I think it would be a very fragile thing In practice: if you have even one variable in the context that isn't pickleable, your code that uses a ProcessPool would stop working. I would defer Context pickleability to 3.8+.

Yury

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