dns.asyncresolver timeout

[LizardBlizzard]

Hi,
While experimenting with dns.asyncresolver I encountered an error which occurs only on my Windows 10 machine and not on WSL or other Linux hosts.

Running the following code throws a timeout exception:

import asyncio
import dns.asyncresolver
import dns.asyncbackend
import dns.exception
from typing import List


async def asyncquery(target, type="A"):
    record_type = "A"
    resolver = dns.asyncresolver.Resolver()
    resolver.nameservers = ["1.1.1.1", "8.8.8.8"]
    resolver.timeout = 10.0
    resolver.lifetime = 10.0

    try:
        answers = await resolver.resolve(target, rdtype=record_type)
        records = [rdata for rdata in answers]
    except dns.resolver.NoAnswer:
        print(f'{target} query returned no answer')
        return None
    except dns.exception.Timeout:
        print(f'{target} query timed out')
        return None
    return records


if __name__ == "__main__":
    target = "google.com"
    res = asyncio.run(asyncquery(target, "A"))
    if res:
        print(f"Results")
        for r in res:
            print(r)

I do see a valid response in Wireshark, but it doesn't seem to be captured by Python.

The non-async resolver works just fine though 🤷‍♀️

Python version: 3.9.1
dnspython: 2.1.0

Any ideas what can cause this?

Thanks for the help!

[rthalley]

I am no windows expert at all, but I ran this on a windows server 2019 vm and saw the same error you did. I added a bunch of debugging and it looks like loop.create_datagram_endpoint() is generating an error that fails the protocol. The protocol thus never completes, and you get a timeout. The error is "[WinError 10022] An invalid argument was supplied". AFAIK this is not any of the arguments I supplied, and I'm wondering if this is possibly a regression in Python 3.9. Before I had unfixable-by-me Azure problems, we tested dnspython on Windows and all of the async stuff worked.

I might try to look into this more, but if you try using "trio" or "curio" for async stuff, they still work. I like either of them a lot better than asyncio, so if you don't need asyncio, you might check them out!

[rthalley]

fixed.

[LizardBlizzard]

@rthalley Thanks, new version works like a charm!

[altendky]

Any expectations of releasing 2.1.1 or 2.2? I don't see tags nor releases on PyPI.

[rthalley]

I'm aiming for 2.2 by the end of the year. No 2.1.1.