ident_func when running within gunicorn+gaiohttp

[urbaniak]

LocalManager.ident_func should be set to asyncio.Task.current_task when running under gunicorn+gaiohttp.

Currently if we're running with gaiohttp the LocalManager mixes the context of different tasks :(

Have no idea how to properly implement the detection if we're running under eventlet (under python3) or asyncio, just hacked my own greenlet module which returns the proper task id.

[RonnyPfannschmidt]

the default is only aware of greenlets/threads, its unclear how to deal with something more complex

LocalManager can be given a custom ident function in the constructor, but its unclear how to determine the deployment situation

[urbaniak]

Maybe we can combine all available task identifiers?

Something like that:

identifiers = []

try:
    from greenlet import getcurrent
    identifiers.append(getcurrent)
except ImportError:
    pass

try:
    from thread import get_ident
    identifiers.append(get_ident)
except ImportError:
    pass

try:
    from asyncio.Task import current_task
    identifiers.append(current_task)
except ImportError:
    pass


def identifier():
    return "".join([str(i()) for i in identifiers])

[untitaker]

I don't like the performance implications of that.

I suppose if e.g. greenlet.getcurrent raises an exception if greenlet is not used, we could pop it from identifiers, and that could improve performance a bit again, but there's still some penalty left.

[untitaker]

I wonder if we could use threading.active_count to determine whether to disable the usage of threading.get_ident, and if the other libs support something similar.

[urbaniak]

Similar thing can be achieved by using asyncio.get_event_loop().is_running() on asyncio.

[urbaniak]

Any chances to get that one resolved somehow?

We can determine which eventloop is used just once at the startup, that won't cause any performance issues.

[davidism]

Sounds like it's already customizable. Any better detection will happen as we add support for ASGI, rolling this into #1322