Logging with callers filename and line number

[Tero Saarni]

I'm using Logging in my library module for producing trace log of
certain events.

For being more useful these log entries should be associated with the 
filename and line number of *users* code that was issuing the library
call.  This is similar to what Logging itself does since it doesn't
print "logging/__init__.py" as value of %(filename) but instead it
prints users file where logging method (info, error...) was called.

What would be the best way to achieve this also for other modules?


I took a quick look into the code in Logging module to see if it
provides means for controlling what goes into %(filename) and %(lineno)
but I didn't find any. I then ended up in subclassing Logger and
redefining Logger.findCaller() to skip a list of files instead of just
one file. Then in my library module I can add current file name into
the list of file names which logger will skip.

Does this seem like sensible solution for you:


import logging
import sys
import os

srcfilelist = [ logging._srcfile, os.path.normcase(__file__) ]

class MyLogger(logging.Logger):

     def findCaller(self):
         f = sys._getframe(1)
         while 1:
             co = f.f_code
             filename = os.path.normcase(co.co_filename)
             if filename in srcfilelist:
                 f = f.f_back
                 continue
             return filename, f.f_lineno

logging.setLoggerClass(MyLogger)



---
Tero