Issue 2697: Logging ancestors ignored after configuration (original) (raw)

Issue2697

Created on 2008-04-26 13:46 by acooke, last changed 2022-04-11 14:56 by admin. This issue is now closed.

Messages (4)
msg65843 - (view)	Author: andrew cooke (acooke)	Date: 2008-04-26 13:46
I am seeing some odd behaviour with logging which would be explained if loggers that are not defined explicitly (but which are controlled via their ancestors) must be created after the logging system is configured via fileConfig(). That's a bit abstract, so here's the problem itself: I define my log within a module by doing import logging log = logging.getLogger(__name__) Now typically __name__ will be something like "acooke.utils.foo". That happens before the application configures logging, which it does by calling logging.config.fileConfig() to load a configuration. If I do that, then I don't see any logging output from "acooke.utils.foo" (when using "log" from above after "fileConfig" has been called) unless I explicitly define a logger with that name. Neither root nor an "acooke" logger, defined in the config file, are called. One way to handle this is to make creation of module-level Loggers lazy, and make sure that logging initialisation occurs before any other logging is actually used (which is not so hard - just init log at the start of the application). Of course, there's a performance hit... For example: class Log(object): def __init__(self, name): super(Log, self).__init__() self._name = name self._lazy = None def __getattr__(self, key): if not self._lazy: self._lazy = logging.getLogger(self._name) return getattr(self._lazy, key) and then, in some module: from acooke.util.log import Log log = Log(__name__) [...] class Foo(object): def my_method(self): log.debug("this works as expected")
msg65915 - (view)	Author: Vinay Sajip (vinay.sajip) *	Date: 2008-04-28 13:15
This is not a bug - it's by design, as I explained in my reply to your posting on comp.lang.python. In my reply, I suggested how you could avoid problems.
msg66265 - (view)	Author: Yap Sok Ann (sayap)	Date: 2008-05-05 09:56
I'd think that it is a rather common situation where one wants to use use both fileConfig and module-level logger. As of now, the workaround suggested by Andrew seems to be the only viable way to achieve that. The alternative approach mentioned, i.e. to name all loggers explicitly in the configuration file, is just too unintuitive.
msg66300 - (view)	Author: andrew cooke (acooke)	Date: 2008-05-06 01:41
Got more important things than this to worry about, but yes, original response not very helpful. In a perfect world this might be either justified more clearly or addressed. OTOH, I get the impression hardly anyone uses this package (docs were pretty opaque...) Also, isn't this a "won't fix" rather than an "invalid"?