I would caution against rushing into anything rash here. Nathaniel's post will stand as one of the most influential posts (about async I/O in Python) of this generation, and curio is a beacon of clarity compared to asyncio. However, asyncio has a much bigger responsibility at this point, as it's in the stdlib, and it must continue to support its existing APIs, on all supported platforms, whether we like them or not.

I would love to see a design for a new API that focuses more on coroutines. But it should be a new PEP aimed at Python 3.7 or 3.8.

I am tempted to start defending asyncio, but I'll resist, because nothing good can come from that.

On Mon, Nov 7, 2016 at 11:41 AM, Glyph Lefkowitz <glyph@twistedmatrix.com> wrote:

On Nov 7, 2016, at 11:08 AM, Yury Selivanov <yselivanov@gmail.com> wrote:

[..]

Sorry, this was a bit tongue in cheek.  This was something I said to Guido at the *very* beginning of Tulip development, when asked about mistakes Twisted has made: "don't have a global event loop, you'll never get away from it".

I still think getting rid of a global loop would always be an improvement, although I suspect it's too late at this point.  `await current_event_loop()` might make more sense in Asyncio as that's not really "global", similar to Curio's trap of the same design; however, I assume that this was an intentional design disagreement for a reason and I don't see that reason as having changed (as Yury indicates).

The latest update of get_event_loop is a step in the right direction. At least now we can document the best practices:

1. Have one “main” coroutine to bootstrap/run your program;

2. Don’t design APIs that accept the loop parameter; instead design coroutine-first APIs and use get_event_loop in your library if you absolutely need the loop.

3. I want to add “asyncio.main(coro)” function, which would create the loop, run the “coro” coroutine, and correctly clean everything up.

What you propose, IIUC is a step further:

* Deprecate get_event_loop();

* Add “current_event_loop()” coroutine.

This will enforce (1) and (2), making asyncio library devs/users to focus more on coroutines and async/await.

Am I understanding this all correctly?

Yep.  It's not so much making users focus more on coroutines, as having a way to pass a loop to a coroutine that is explicit (the coro needs to be scheduled on a loop already, so the binding has been explicitly specified) but unobtrusive.

-glyph

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