[Python-Dev] provisional status for asyncio

[Yury Selivanov]

Victor,

On 2015-08-28 5:01 AM, Victor Stinner wrote:
> Hi,
>
> 2015-08-27 23:15 GMT+02:00 Yury Selivanov <yselivanov.ml at gmail.com>:
>> Recently, in an asyncio related issue [1], Guido said that new features
>> for asyncio have to wait till 3.6, since asyncio is no longer a provisional
>> package. (...)
>> For example, there is an issue [2] to add starttls support to asyncio.
>> (...)
>> Aside from adding new APIs, we also have to improve debugging
>> capabilities.
>> (...)
> I would propose something more radical: remove asyncio from the stdlib.

I too would enjoy more frequent release schedule of asyncio.

Unfortunately, separating it from the standard library is something
that I don't think we can do so late in the 3.5 release candidates
process.


>
> PEP 411: "While it is considered an unlikely outcome, such packages
> *may even be removed* from the standard library without a deprecation
> period if the concerns regarding their API or maintenance prove
> well-founded."
>
> As an asyncio developer, I'm not sure that asyncio fits well into the
> Python stdlib. The release cycle of feature release is long (18
> months? or more?), the release cycle for bugfix release is sometimes
> also too long (1 month at least). It's also frustrating to have subtle
> API differences between Python 3.3, 3.4 and 3.5. For example,
> asyncio.JoinableQueue was removed in Python 3.5, asyncio.Queue can
> *now* be used instead, but asyncio.JoinableQueue should be used on
> older Python version... It means that you have to write different code
> depending on your Python version to support all Python versions.
>
> I can give much more examples of missing asyncio features. Example:
> Windows proactor event loop doesn't support signals (CTRL+C) nor UDP.
>
> asyncio is moving so fast, that changes are not documented at all in
> Misc/NEWS or Doc/whatsnews/x.y.rst. I tried to document changes in my
> fork Trollius. See its changelog to have an idea how fast asyncio is
> still changing:
> http://trollius.readthedocs.org/changelog.html
>
> I don't know how users will react to the removal of asyncio from the
> stdlib ("asyncio is not trusted/supported by Python?").

That's another concern.

>
> The idea is to install it using pip: "pip install asyncio". The major
> difference is that "pip install -U asyncio" allows to retrieve the
> latest asyncio version, independently of your Python version. Hum, I
> don't know if it works with Python 3.4 (which "asyncio" module is used
> in this case?).

The one from the stdlib.

>
> Developing asyncio only on Github would avoid the risk of having
> patches temporary only in Github or only in CPython. It avoids the
> need to synchronize the Git (Github) and Mercurial (CPython)
> repositories.
>
>
> Compare Python release dates with Twisted, Tornado and eventlet release dates.
>
> Twisted releases:
>
> * 2015-01-30: 15.0.0
> * 2015-04-13: 15.1.0
> * 2015-05-19: 15.2.0
> * 2015-08-04: 15.3.0
>
> Tornado releases:
>
> * 2014-07-15: 4.0
> * 2015-02-07: 4.1
> * 2015-05-27: 4.2
> * 2015-07-17: 4.2.1
>
> eventlet releases:
>
> * 2015-02-25: 0.17.1
> * 2015-04-03: 0.17.2
> * 2015-04-09: 0.17.3
> * 2015-05-08: 0.17.4
>


These are very good stats.  It shows that even mature async libraries
require frequent release cycles.

Anyways, I vote for at least keeping asyncio provisional in 3.5.x.

I'd be glad if we can consider to have more bugfix releases of 3.5
(and 3.6), say every 3 months.


Yury