[Python-ideas] Making concurrent.futures.Futures awaitable

[Guido van Rossum]

FWIW, I am against this (as Alex already knows), for the same reasons I
didn't like Nick's proposal. Fuzzing the difference between threads and
asyncio tasks is IMO asking for problems -- people will stop understanding
what they are doing and then be bitten when they least need it.

The example code should be written using loop.run_in_executor(). (This
requires that do_something_cpu_heavy() be refactored into a function that
does the work and a wrapper that creates the concurrent.futures.Future.)

On Fri, Aug 7, 2015 at 6:51 PM, Alex Grönholm <alex.gronholm at nextday.fi>
wrote:

> There's an open issue for adding support for awaiting for
> concurrent.futures.Futures here:
> http://bugs.python.org/issue24383
>
> This is about writing code like this:
>
> async def handler(self):
>
>     result = await some_blocking_api.do_something_cpu_heavy()
>
>     await self.write(result)
>
>
> As it stands, without this feature, some boilerplate is required:
>
> from asyncio import wrap_future
>
> async def handler(self):
>
>     result = await wrap_future(some_blocking_api.do_something_cpu_heavy())
>
>     await self.write(result)
>
>
> I wrote a patch (with tests by Yury Selivanov) that adds __await__() to
> concurrent.futures.Future
> and augments the asyncio Task class to handle concurrent Futures.
>
> My arguments on why we should add this:
>
>    - it eliminates the boilerplate code, reducing complexity
>    - it also makes concurrent Futures work with "yield from" style
>    non-native coroutines
>    - it does not interfere with any existing functionality
>    - standard library components should work with each other
>
>
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-- 
--Guido van Rossum (python.org/~guido)
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