Python indentation \ context level to log prefix length

Question

My idea is to make a context logging scheme as showed on the example below:

[   DEBUG] Parsing dialogs files [   DEBUG] ... [DialogGroup_001] [   DEBUG] ...... Indexing dialog xml file [c:\001_dlg.xml] [   DEBUG] ......... dialog [LobbyA] [   DEBUG] ............ speech nodes [3] [   DEBUG] ............... [LobbyA_01] [   DEBUG] ............... [LobbyA_02] [   DEBUG] ............... [LobbyA_03] [   DEBUG] ............ sms nodes [0] [   DEBUG] ......... dialog [LobbyB] [   DEBUG] ............ speech nodes [3] [   DEBUG] ............... [LobbyB_01] [   DEBUG] ............... [LobbyB_02] [   DEBUG] ............... [LobbyB_03] [   DEBUG] ............ sms nodes [0] [   DEBUG] ... [DialogGroup_002] [   DEBUG] ...... Indexing dialog xml file [c:\002_dlg.xml] [   DEBUG] ......... dialog [HighGroundsA] [   DEBUG] ............ speech nodes [3] [   DEBUG] ............... [HighGroundsA_01] [   DEBUG] ............... [HighGroundsA_02] [   DEBUG] ............... [HighGroundsA_03] [   DEBUG] ............ sms nodes [0] 

At this point, I'm using Python's logging module with custom, hand-written prefixes when logging, for example:

(...)  log.debug('') log.debug('Parsing dialogs files') for dlg in defDlgList:     log.debug('... [{0}]'.format(dlg))  (...) 

It's working quite ok, but there are some subtle problems, for example: when logging from inside functions - they may be called from various scopes and prefix length may vary for each call.

I'm looking for an elegant and invisible way to establish a length of a '...' prefix automatically for each log. I'd rather avoid passing prefix length as a parameter to each function or setting the length using explicit calls, for example:

(...)  logWrapper.debug('') logWrapper.debug('Parsing dialogs files') for dlg in defDlgList:     logWrapper.nextLogLevelBegin()     logWrapper.debug('[{0}]'.format(dlg))     logWrapper.nextLogLevelEnd()  (...) 

Is there a way to get the current indentation level from Python's parser or construct a scope sensitive wrapper class for logging?

Answer 1

Perhaps you can use inspect.getouterframes to find the indentation level:

import inspect import logging  logger=logging.getLogger(__name__)  def debug(msg):     frame,filename,line_number,function_name,lines,index=inspect.getouterframes(         inspect.currentframe())[1]     line=lines[0]     indentation_level=line.find(line.lstrip())     logger.debug('{i} [{m}]'.format(         i='.'*indentation_level,         m=msg                     ))  def foo():         debug('Hi Mom')     for i in range(1):         debug("Now we're cookin")  if __name__=='__main__':     logging.basicConfig(level=logging.DEBUG)     foo() 

yields

DEBUG:__main__:.... [Hi Mom] DEBUG:__main__:........ [Now we're cookin] 

Answer 2

Searching through the docs, I don't really see a way to get current indentation level. The best you can do, is get the current function nesting level, like this:

len(traceback.extract_stack()); 

Example:

import traceback;  def test():     print len(traceback.extract_stack());   print len(traceback.extract_stack()); # prints 1 test(); # prints 2