(Java-ish) 'logging' module in a mood of responsibility and as I am not
overly happy with the current "thickener" style of usage, I want to put
this comment and a alternative most simple default framework for
discussion.
Maybe there are more Python users which like to see that imported
(managed) logging issue more down-to-earth and flexible ? ...
Vinay Sajip wrote:
robert wrote:some packages like paramiko use the logging. I get this messages:
"No handlers could be found for logger xxx" on stderr
Why is un-initialized logging allowed to chatter at all?
You could invoke logging.basicConfig with a level of CRITICAL. This
will generally filter out logging messages.
Meanwhile i looked on logging and its doc:
The doc of for example basicConfig (promising to be quite simple/silent):
"basicConfig( )
Does basic configuration for the logging system by creating a
StreamHandler with a default Formatter and adding it to the root logger.
The functions debug(), info(), warning(), error() and critical() will
call basicConfig() automatically if no handlers are defined for the root
logger. "
=> So far I don't get any idea what will happen after doing this. What
is a StreamHandler? a "default Formatter"? CRITICAL? what is this
default magic behavior? even if silent behavior is installed log(),
debug() consume still a lot of execution time => I have to read the
logging code anyway => for my needs i rendered dead the Logger() in
app-init / dead the line in logging which chatters within my standard
set of Python patches.
I looked around a little more and think, that logging it is really a
_FRAMEWORK_ - non-pythonic . a declarative monster.
Meaning: too big the interface and too big its basic footprint. without
a decent scaling. too loud. it takes lots of time until one understands
the basics. even the simplest setup example has not less than 8 lines -
strange "filehandlers" and "formatters" are going on - and it is a
framework which does a lot of obscure things, its class collection reads
more like an magic application only understandable by its immediate
programmers - rather than a stdlib part.
Its almost a Java-ish ego class bunch.
Some wide spread packages like paramiko use it already - inside stdlib
only cookielib so far. Yet, just for providing the option they are
costly pre-importing almost the whole framework functionality (in
memory, frozen apps etc.) and have considerable costs during execution
(regarding my step-in debugging sessions: seems to do very very late
dispatching).
Python is still not an OS on its own but a programming language/library
which should fit into OS'es.
( though they meanwhile put the CJK codecs etc. into the python core !?
:-) )
Yes, one could use such functionality - but one does only in rarest cases.
I did and do logging a lot, but always had quite simple paths. I'd
usually still not go though that framework in almost all cases, because
it would require many hours until I really know whats going magically in
all kinds of cases.
99% of my app logging needs were and are fulfilled by a simple direct
module function as simple as:
def doLog(text,level,**kwattrs):
# in case write to file or whatever ...
and so I simply know really what will happen. Collecting all logs is
also so easy with Python, that it could be _enabled_ by a much much
simpler and pythonic one-function-framework: a empty log-hook function
in the python __builtins__:
================================================== =======
def loglog(text, channel='default', level=0, **kwattrs):
pass
================================================== =======
yet there could go any complex hierarchical channel names through that
like channel="mypackage.mymodule.subtheme" or even multi-hierarchical
channel classes/objects similar to exception-class-catching in addition
to string-catching. Example:
================================================== =======
class MyLogChannelAA(MyLogChannelA, MyLogAspectXY)
loglog(text, MyLogChannelAA, __debug__, lcls=locals() )
================================================== =======
If that simple would be the recommended standard logging interface in
Python, I think, really a significant fraction of Python programmers
would first understand and than use ( call and consume ) it - and
(decent) modules would not blow up the machine unconditionally just for
a mere specialized option.
For massive usage apps could shortcut THEMSELVES with bloomy names and
level-constants like logdebug() logerror() ....
(Recommendations at best - no more framework.)
Still this would be flexible enough and a super-hierarchical obscure
logger and handler collection as exposed by "logging" or any other
alternative could still be hooked in, while no module which does logging
has to PRE-IMPORT SUCH A FAT SPECIAL LOGGING FRAMEWORK.
Un-initialized logging chatters because in development environments,
it's useful to be able to spot misconfigured loggers. For production
use, set logging.raiseExceptions to 0 and logging should then be quiet.
Think a potentially "misconfigured logger" is not a reason to chatter.
If there is an error in setup you'd 99.99% get an exception. If you
really totally forget to setup - you simply have forgotten as you can
forget many things. If you really want log's you'll have 1000 chances as
developer to see that there are no logs - and add the setup.
My opinion: _By default_ logging should really
* be totally silent
* not import all the logging code and handler classes etc. (but only a
minimal stub or do ** (see below))
* consume only minimum execution time: <if-not-initialized: return>
Consider a typical complex program: Hundreds and thousands of things
have to be be set up and configured which are much more important than a
debug logger. Yet not every imported library and every class yells
because it was not used or not basicConfig'ed :-). The logging is not
the center of the world. In 99% only the developer of a module
uses/wants the log output.
I see there were already other complaints about this chattering - and
other people also wondered how to make it silent.
--
In cookielib recently the logging initialization has been **virtualized
=> its not imported / necessary (in frozen apps) until the cookielib
debugging was not really requested.
Think thats a better/acceptable style of use and such guidline should be
put at the top of the logging docs to complete/alternate the above 3 issues.
That all maybe could be healed most easily by the proposed
__builtin__.loglog in Python : not unconditional wiring to such a
specific and fat package.
-robert
