probably should go to 1.24.0 since it fixes a regression introduced in 1.22.0

o there are docs for channel.. need to update them

Great work!

Thanks. I'll work on a PR for aiodns once this makes it into a release

It looks like we might not have to do it manually if we turn on the event thread c-ares/c-ares#759

If the event thread can be turned on with some flag, adding support for it would be good.

I wouldn't make it the default though.

I agree. I'm not sure it will work with asyncio anyways.

Researching that today

Its explicitly not compatible with ARES_OPT_SOCK_STATE_CB so it looks like we have to do it manually

Looks like its using inotify.
https://github.com/c-ares/c-ares/pull/759/files#diff-28db3f50243f279af6a0756548de982396815e487d33120e935702549711fd3bR109

aiodns could implement it using asyncinotify (if installed only) ...similar to how we do usb watching in https://github.com/Bluetooth-Devices/aiousbwatcher/blob/main/src/aiousbwatcher/impl.py

Its explicitly not compatible with ARES_OPT_SOCK_STATE_CB so it looks like we have to do it manually

I suspected as much, since it uses threading...

aiodns could implement it using asyncinotify (if installed only) ...similar to how we do usb watching in https://github.com/Bluetooth-Devices/aiousbwatcher/blob/main/src/aiousbwatcher/impl.py

IMHO that's kind a big lift for a simple DNS library. You'd also need to port the implementation to Windows and macOS. I'd expose the reinit method and let users handle it.

Its explicitly not compatible with ARES_OPT_SOCK_STATE_CB so it looks like we have to do it manually

I suspected as much, since it uses threading...

aiodns could implement it using asyncinotify (if installed only) ...similar to how we do usb watching in Bluetooth-Devices/aiousbwatcher@main/src/aiousbwatcher/impl.py

IMHO that's kind a big lift for a simple DNS library. You'd also need to port the implementation to Windows and macOS. I'd expose the reinit method and let users handle it.

Another option would be to create a new lib once we have reinit in aiodns.DNSResolver.

Maybe aiodns-auto-reinit which subclasses aiodns.DNSResolver and implements the automatic reinit. We currently don't install aiodns on windows with aiohttp because of the SelectorEventLoop requirement so we likely wouldn't need to implement windows support (could of course be added later if someone really wants it)

Another option could be to explore using the builtin threaded mode, and use run_in_executor to make sure our callbacks gets called in the given thread.

That's a bit more of a question for aiodns, but this lib would need to at least make it possible to enable that mode.

I guess it would work with call soon thread safe, however, running in another thread would probably not be so great for performance since we now have the context switching...

It kinda already works that way for those not using pycares, they will end up running getaddrinfo on a thread...

Someone with enough motivation could benchmark it ;-)

It kinda already works that way for those not using pycares, they will end up running getaddrinfo on a thread...

Someone with enough motivation could benchmark it ;-)

At least with Home Assistant, we know that's much slower because of the cost the context switch, which is why we use the AsyncResolver, and thus aiodns in the first place. We also had a problem with a thundering heard at startup where the executor would get swamped because of all the requests.

Looking at the example https://c-ares.org/docs.html#examples .. the callbacks might be thread-safe so even if they run in another thread the callback might still be ok to consume in the event loop. need to dig some more

So it looks like we can make the calls from the event loop thread and that looks like it's thread-safe but the callbacks will be delivered in another thread so we would need to deliver it back to the event loop future with loop.call_soon_threadsafe. While not great that is still relatively efficient as we don't have all the python overhead to wrap the future running in another thread.

Sounds like a plan! Would you like to add support for the threaded mode here, then I can cut a release and you can experiment with aiodns?

I think whatever happens in aiodns the threaded mode is a nice addition to this low(er) level library.

Sounds good. About to get on a flight back to the US from FRA so will probably be later this week that I work it out (once I recover from the jet lag)

Safe flight and thanks for your work!

implemented in #220

aiodns PR is aio-libs/aiodns#145

used strace to verify auto reloads, so it should solve aio-libs/aiodns#124