Fix warning that coroutine decorator is deprecated since Python 3.8

[dhimmel]

Our project currently uses ratelimiter-1.2.0.post0, the latest version on PyPI.

Python 3.8 has been released and we're adding a py28 CI test for our project, which resulted in the following warning:

  /home/travis/virtualenv/python3.8.0/lib/python3.8/site-packages/ratelimiter.py:127: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead
    __aexit__ = asyncio.coroutine(__exit__)

While the master branch has unreleased commits that weren't in the version we're testing, I believe the warning would still occur on the latest master commit at the following line:

ratelimiter/ratelimiter/_async.py

Line 35 in da78a45

__aexit__ = asyncio.coroutine(RateLimiter.__exit__)

Is it possible to update the code to no longer create the warning and release a new version to PyPI with the update?

[dhimmel]

Ping @RazerM

[RazerM]

Can you submit a PR?

[dhimmel]

Can you submit a PR?

I read a bit about the difference between @asyncio.coroutine and async def. But I'm not familiar enough with Python's async to confidently fix the warning.

[kapilt]

i'm running into the same issue. it looks like theres other issues with the async implementation here, its protecting async.Lock initialization with a the synchronous thread lock, and at the moment for exit it just calls through to baseclass exit, which is just using the thread lock not the async lock. putting an async coroutine around a blocking call doesn't make it not blocking

[kapilt]

Can you submit a PR?

I read a bit about the difference between @asyncio.coroutine and async def. But I'm not familiar enough with Python's async to confidently fix the warning.

fwiw, in the context of the usage here the delta really isn't very material afaics.

[musicinmybrain]

The deprecated asyncio.coroutine was scheduled for removal in Python 3.10, but that didn’t end up happening. However, it is removed in current development versions of Python 3.11, so this still needs to be dealt with.

[MilesCranmer]

FYI this was officially removed in Python 3.11 so dependent packages are now breaking. @RazerM

[brainysmurf]

Also seeing this. If this isn't going to be fixed is there an alternative?

[MilesCranmer]

Snakemake might switch to throttler instead: snakemake/snakemake#1958