Comment by throwawaymaths a day ago
hm maybe. i guess ive only used python in situations where it injects it into amain so i could have been confused. i thought python async was a wrapper around generators, and so the mechanism cant be instantiated in multiple places. i stand corrected.
> no good reason to have more than one event loop
Per thread—once you start working in multiple threads you have the choice to have one global event loop, which comes at the cost of all async code being effectively serialized as far as threads are concerned*, or one event loop per thread.
* Which can be fine if your program is mostly not async but you have that one stubborn library. Yay async virality.
Because you have a main application running a web server and a daemon worker thread performing potentially long running tasks that use async libraries and you don't want to block the responsiveness of your web server. It's really not that bad, at least in Python.
Oh no you're right it's a pain in the ass and weird. But I think it's the way because there's no good reason to have more than one event loop.
Also... maybe it started out as generator wrappers? I think I read something that said that.