Hi!

I was looking to add a custom logging filter to my aiohttp server during exception that are catched here.

It's useful and easy to do, but, it occurs that, in my custom logging filter, I can't find contextvars that I have created in my request handler task.

Two things caused this problem:

• aiohttp handled requests in a sub-Task, and catched exceptions in the parent Task.
  → This was fixed in aio-libs/aiohttp@9997cae (because users asked to be able to access contextvars -- like us). It was even backported to aiohttp version 3.7.
• Sentry-aiohttp integration handles requests in a sub-Task too.

Python documentation on Tasks here. One important thing is that they reset contextvars.

To summarize:

   aiohttp                               logging exception
      +                                        ^
      |                                        |
      | asyncio.create_task(handle_request())  | contextvars didn't go up again
      |                                        | (it's fixed now)
      |                                        |
      v                                        |
   Sentry                                      |
      +                                        |
      |                                        |
      | asyncio.create_task(handle_request())  | contextvars don't go up
      |                                        |
      v                                        |
I set contextvars        +---------------------+

                                   Exception

As long as the issue is not fixed in Sentry, I still can't use contextvars to log custom data using the standard Python logging library.
The only solution is to disable Sentry, then logging works OK with contextvars.

Any idea how to fix this in Sentry-aiohttp code?
I'd be happy to open a PR, but I'm not familiar enough with Sentry code, or Python in general, thus I need some help at least.