> Django 3.0 begins our journey to making Django fully async-capable by providing support for running as an ASGI application.
Bleh. ASGI is probably the worst implementation I can think of for a common async interface. Stringly-typed callbacks? async generators exist for a good reason. It's also very asyncio-centric, and asyncio is Not Good.
Having worked and developed with it extensively for over a year now, ASGI is one of the most elegant and well-designed interfaces I've seen.
Just wanted to address this:
> async generators exist for a good reason.
While the idea of using async generators might sound attractive at first, there's so much more to ASGI than exchanging messages in both directions.
Even on that aspect, I'd be interested in knowing how you'd achieve bidirectional communication async generators. How would the ASGI server call into the application and handle messages coming both ways? Surely, it can't just `async for message in agen: ...`, as that would only replicate the `send()` ASGI callback — what about `receive()`?
Besides, how would middleware look? Would it be as simple as wrapping `receive()` and `send()` into whichever other callable adds the functionality your middleware needs?
And you probably wouldn't be able to support all the possible syntactical implementations allowed by the notion of a Python callable: functions, classes, callable class instances.
So, yeah, I think ASGI is a beast.
Also, I wholeheartedly congratulate the Django team for pushing the standard out there and driving the Python async web ecosystem forward. You rock!
Yield is two-way. ``result = await agen.asend(next_message)` ` et al.
> Having worked and developed with it extensively for over a year now, ASGI is one of the most elegant and well-designed interfaces I've seen.
Having worked with Python async for 3 years, anything that asyncio touches is completely poisoned. ASGI is another in the line of terribleness of the modern async ecosystem.
> Besides, how would middleware look?
A second async generator.
> And you probably wouldn't be able to support all the possible syntactical implementations allowed by the notion of a Python callable
Require an async generator. Done!
> Also, I wholeheartedly congratulate the Django team for pushing the standard out there and driving the Python async web ecosystem forward. You rock!
Much like asyncio, something isn't good just because it's being pushed.
It's still limited. To get a result you need to send something. Using it for something that's not strictly request-response can get complex.
> Having worked with Python async for 3 years, anything that asyncio touches is completely poisoned. ASGI is another in the line of terribleness of the modern async ecosystem.
That's your own bias. I also used asyncio from the beginning and got a different opinion. The asyncio package that comes with python is low level and is meant for building frameworks. If you used aiohttp, asyncpg and other packages packages build on top of asyncio it's actually quite enjoyable.
There's the problem. WSGI is fundamentally flawed too - it could also be using generators for a two-way communication channel instead of stringly typed callbacks.
In a world where Python has optional static type hints, it would be nice to have concrete objects passed too.
* You can absolutely stay within structured concurrency constraints using ASGI.
* The ASGI spec doesn’t have anything to do with asyncio. It’s purely an async/await interface - You can build against it just fine using other concurrency backends.