On 2023-01-05 12:29:33 -0800, Grant Edwards wrote: > On 2023-01-05, Thomas Passin <li...@tompassin.net> wrote: > > > The logging system is so configurable that... > > I find it almost impossible to use unless I copy a working example I > find somewhere. ;)
I usually copy the working example from my previous project ;-).
I think the general structure is clear enough. You need a formatter to
format your log messages, a handler to actually write them and finally a
logger to determine what goes where. I can look up the details in the
docs but generally the logging is always the same (except for path names
and log levels), so I can just copy the config from last time and adjust
those.
So I might have a config.py like this:
# ...
logging = {
"version": 1,
"disable_existing_loggers": False,
"formatters": {
"standard": {
"format": "%(asctime)s %(levelname)s %(name)s %(funcName)s
%(lineno)d | %(message)s"
}
},
"handlers": {
"file": {
"class": "switchinglogfilehandlers.TimeoutSwitchingFileHandler",
"formatter": "standard",
"filename": "/var/log/www/XXX.hjp.at/XXX.",
},
},
"loggers": {
"": {
"handlers": ["file"],
"level": "INFO"
}
}
}
# ...
And then my application would start like this:
import logging
import logging.config
import config
logging.config.dictConfig(config.logging)
log = logging.getLogger(__name__)
Plus typically every other source file contains
import logging
log = logging.getLogger(__name__)
somewhere near the start.
Then I can just scatter my log.debug(...) or whatever whereever I want.
When I decide that I need debug output from one module, I'll just add a
logger. Or if some library is too chatty I'll add another logger to shut
it up - no programming, just a few extra lines in a dict.
(Instead of a config.py I might use a json file, especially if I expect
the config to change often.)
> I'm not at all surprised that the OP didn't understand how it
> works.
It probably helps to have worked with log4j before that. The structure
is very similar, although I find Python logging easier to use (but then
I never did much Java programming so that's probably just a matter of
familiarity.
hp
PS: The TimeoutSwitchingFileHandler mentioned above is one I wrote
myself. You can find it on PyPI, but be warned that the
documentation is (still) quite lacking.
--
_ | Peter J. Holzer | Story must make more sense than reality.
|_|_) | |
| | | h...@hjp.at | -- Charles Stross, "Creative writing
__/ | http://www.hjp.at/ | challenge!"
signature.asc
Description: PGP signature
-- https://mail.python.org/mailman/listinfo/python-list
