[Python-ideas] Add a generic async IO poller/reactor to select module

[Calvin Spealman]

On Fri, May 25, 2012 at 9:53 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On May 25, 2012 7:33 PM, "Calvin Spealman" <ironfroggy at gmail.com> wrote:
>>
>> On Wed, May 23, 2012 at 9:32 PM, Giampaolo Rodolà <g.rodola at gmail.com>
>> wrote:
>> > Users willing to support multiple event loops such as wx, gtk etc can
>> > do:
>> >
>> >>>> while 1:
>> > ...       poller.poll(timeout=0.1, blocking=False)
>> > ...       otherpoller.poll()
>> >
>> >
>> > Basically, this would be the whole API.
>> >
>> > Thoughts?
>> >
>>
>> Frankly, I don't think this deserves a PEP at all, or even to consider
>> one *yet*.
>>
>> Building a new API and a new library from scratch seems a frail
>> comparison to testing
>> a library in the real world, it having real uses, and then being
>> incorporated into the
>> stdlib. The problem here, of course, is that all the real-world
>> solutions (ie, Twisted)
>> include far more than the reactor.
>
>
> No, the specific call at the PyCon US 2011 language summit was for a PEP
> that proposed a *new* event loop for the standard library that:
> 1. Provides simple event loop functionality in the standard library, as an
> improved alternative to asyncore for small apps that don't require the full
> power of a framework like Twisted (think things like little IRC bots, TCP
> echo servers, or testing of async components)
> 2. Provides a clean migration path to a production grade reactor like
> Twisted's
> 3. Makes it easier for multiple event loop based frameworks (e.g. tkinter,
> wxPython, PySide, Twisted) to all cooperate within the same process
>
> What we're after is something for the stdlib that is to event loops/reactors
> as wsgiref is to production grade WSGI servers like mod_wsgi and nginx.
> asyncore isn't it, because the migration path isn't clean.
>
> PEP 3153 currently spends a lot of time talking about transports and
> protocols, but doesn't answer those 3 core questions:
>
> 1. How do I write a simple IRC bot or TCP echo server?
> 2. How do I migrate my simple app to a production grade reactor like
> Twisted's?
> 3. How do I run two different concurrent.eventloop compatible reactors in
> the same process?
>
> As far as I can tell, PEP 3153 wants to handle all that by merging the I/O
> stacks of all the frameworks first, which strikes me as being *way* too
> ambitious for a first step. If we can't even figure out a common abstraction
> for the reactor level (ala WSGI), how are we ever going to agree on a
> standard async I/O abstraction?

Obviously, for a man with many opinions I miss out on too many conversations
and too many potential actions. I should make steps to correct this in
the future.
Thanks for clearing this up.

> Cheers,
> Nick.
>



-- 
Read my blog! I depend on your acceptance of my opinion! I am interesting!
http://techblog.ironfroggy.com/
Follow me if you're into that sort of thing: http://www.twitter.com/ironfroggy