Django instrumentation silently doesn't work for ASGI requests

[alexmojaki]

A user couldn't get the Django instrumentation working (https://pydanticlogfire.slack.com/archives/C06EDRBSAH3/p1722460460137619?thread_ts=1722440635.372479&cid=C06EDRBSAH3). With difficulty we realised that it was because they were using ASGI. In opentelemetry/instrumentation/django/middleware/otel_middleware.py you can see that ASGI requests are silently ignored when opentelemetry-instrumentation-asgi isn't installed.

Firstly, we should document this loudly.

Then for people who miss this point, we should either:

1. Try to detect ASGI requests and warn the user if needed. Not sure how easy this is.
2. Add a mandatory is_asgi parameter to instrument_django to force the user to tell us the situation, then raise an error if needed.
3. Always install opentelemetry-instrumentation-asgi with the django extra.
4. Remove the django extra and replace it with django-wsgi and django-asgi.

@samuelcolvin what do you think?

[Kludex]

Remove the django extra and replace it with django-wsgi and django-asgi.

We can also just add django-async.

[Kludex]

The first step here is to document this.

[alexmojaki]

Remove the django extra and replace it with django-wsgi and django-asgi.

We can also just add django-async.

The idea is that the user has to be aware of the distinction and make an explicit choice. If they don't check docs carefully they may easily think that pip install logfire[django] should just work, they won't get an error at any point.

[Kludex]

open-telemetry/opentelemetry-python-contrib#1051 😆

[Kludex]

The easiest here is to add opentelemetry-instrumentation-asgi to the django extras...

[Kludex]

In the meantime, while we don't solve this... I've added a note to the docs: #630

[Kludex]

We now have a note on the top of the Django page about this: