How to write custom logging methods for custom logging levels

Question

Hi
I would like to expand my logger (done by logging.getLogger ("rrcheck")) using my own methods, such as: def warnpfx(...):

How to do it best?

My initial desire is for the root log to write everything to a file and optionally change the logger ("rrcheck") that writes to stdout, but the latter should also have some other methods and levels. I need some messages to be prefixed with "! PFXWRN" (but only those that were collected on stdout), and leave other messages unchanged. I would also like to set the logging level separately for root and for the named logger.

This is my code:

class CheloExtendedLogger(logging.Logger):
    """
    Custom logger class with additional levels and methods
    """
    WARNPFX = logging.WARNING+1

    def __init__(self, name):
        logging.Logger.__init__(self, name, logging.DEBUG)                

        logging.addLevelName(self.WARNPFX, 'WARNING')

        console = logging.StreamHandler()
        console.setLevel(logging.DEBUG)
        # create formatter and add it to the handlers
        formatter = logging.Formatter("%(asctime)s [%(funcName)s: %(filename)s,%(lineno)d] %(message)s")
        console.setFormatter(formatter)

        # add the handlers to logger
        self.addHandler(console)

        return

    def warnpfx(self, msg, *args, **kw):
        self.log(self.WARNPFX, "! PFXWRN %s" % msg, *args, **kw)


logging.setLoggerClass(CheloExtendedLogger)    
rrclogger = logging.getLogger("rrcheck")
rrclogger.setLevel(logging.INFO)

def test():
    rrclogger.debug("DEBUG message")
    rrclogger.info("INFO message")
    rrclogger.warnpfx("warning with prefix")

test()

And this is an output function, and the lilne number is wrong: warnpfx instead of test

2011-02-10 14:36:51,482 [test: log4.py,35] INFO message
2011-02-10 14:36:51,497 [warnpfx: log4.py,26] ! PFXWRN warning with prefix

Maybe my own approach to registration is not the best?
What direction would you suggest (your own registrar, your own handler, your own formatter, etc.)?

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Answer 1

Python, , Logger.findCaller, , logging.py. - self.log CheloExtendedLogger.warnpfx .

, logging.py , : findCaller , logging.py, , ( , , , ). :

class CheloExtendedLogger(logging.Logger):

    [...]

    def findCaller(self):
        """
        Find the stack frame of the caller so that we can note the source
        file name, line number and function name.
        """
        f = logging.currentframe().f_back
        rv = "(unknown file)", 0, "(unknown function)"
        while hasattr(f, "f_code"):
            co = f.f_code
            filename = os.path.normcase(co.co_filename)
            if filename in (_srcfile, logging._srcfile): # This line is modified.
                f = f.f_back
                continue
            rv = (filename, f.f_lineno, co.co_name)
            break
        return rv

_srcfile . , logging.py , , -:

if hasattr(sys, 'frozen'): #support for py2exe
    _srcfile = "logging%s__init__%s" % (os.sep, __file__[-4:])
elif string.lower(__file__[-4:]) in ['.pyc', '.pyo']:
    _srcfile = __file__[:-4] + '.py'
else:
    _srcfile = __file__
_srcfile = os.path.normcase(_srcfile)

, , , .

, :

2011-02-10 16:41:48,108 [test: lg.py,16] INFO message
2011-02-10 16:41:48,171 [test: lg.py,17] ! PFXWRN warning with prefix

, , logging.Logger, , . , , , .