[issue47149] DatagramHandler doing DNS lookup on every log message

[Bruce Merry]

Bruce Merry <bmerry at gmail.com> added the comment:

> If you don’t look it up every time, how do you deal with DNS timeouts?

Do you mean expiring the IP address when the TTL is reached? I suppose that could be an issue for a long-running service, and I don't have a good answer to that. Possibly these days with services meshes and load-balancers it is less of a concern since a logging server can move without changing its IP address.

But it's important for a logging system not to block the service doing the logging (which is one reason for using UDP in the first place). I only discovered this issue because of some flaky DNS servers that would occasionally take several seconds to answer a query, and block the whole asyncio event loop while it waited.

At a minimum it would be useful to document it, so that you know it's something to be concerned about when using DatagramHandler.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue47149>
_______________________________________