fixes https://github.com/spesmilo/electrum/issues/7952
see in particular https://github.com/spesmilo/electrum/issues/7952#issuecomment-1227225602
> So the issue is with the aiorpcx monkey patch in util.py, as it
> relies on side-effecting the asyncio.Task, and it patches Task.cancel.
> However, aiohttp also uses Task.cancel for its own timeouting of the
> http request, with the same Task object, and this confuses timeout_after.
> Ultimately FxThread.run exits.
related https://github.com/kyuupichan/aiorpcX/pull/47
---
note: I am not content at all with this monkey-patching approach,
but at the same time I don't see how to properly fix this handling all
edge-cases in aiorpcx.
python 3.11 is finally adding an implementation of TaskGroup [0] and
an async timeout context manager [1] in the asyncio module of the stdlib.
Looking at the implementations, they look unfeasible to backport:
much of the implementation of asyncio.Task had to be changed for them
to work, and TaskGroup in particular relies on the new ExceptionGroups.
Some of these edge cases we are battling with aiorpcx.curio look
difficult to fix without those stdlib changes...
Anyway, when we bump the min python to 3.11, I look forward to switching
to that code instead, and ripping this stuff out.
[0]: https://docs.python.org/3.11/library/asyncio-task.html#task-groups
[1]: https://docs.python.org/3.11/library/asyncio-task.html#asyncio.timeout
We poll the fx rate provider every 2.5 minutes (unchanged).
Previously if there was any error during a tick, there was no fx rate
available in the client until the next tick.
Now, instead, we keep the last rates received with a 10 minute expiry.
One potential drawback is that previously there was instant feedback
to the user when e.g. changing proxy settings, and this is no longer
the case. E.g. consider a provider that bans Tor exit nodes. If a user
enables using a Tor proxy in the network settings, the fxrate used to
disappear immediately - but now the cached rate would still be
available.
SomberNight
ThomasV
Sander van Grieken