Logging for fun!

gistfile1.txt

loggersS = set()

def logger(loggerName, level, logFile=None):
    '''
    Get a logging instance
    @param  loggerName  name of the logging instance
    @param  level       level in which to log
    @param  logFile     the absolute path to the log file to use. you must have write perms for this!

    @return logging object used for later on
    '''
    # do we already have a logger for this?
    if loggerName in loggersS:
        # we do, so we can just return the logger singleton for this name
        return logging.getLogger(loggerName)

    else:
        # we do not; we need to get the logger singleton for this name for the first time and set it up
        logger = logging.getLogger(loggerName)
        loggersS.add(loggerName)

        # Set the log level
        if level == "INFO":
            logger.setLevel(logging.INFO)
        elif level == "WARN":
            logger.setLevel(logging.WARN)
        elif level == "DEBUG":
            logger.setLevel(logging.DEBUG)
        elif level == "ERROR":
            logger.setLevel(logging.ERROR)
        else:
            pass

        # Some formatters. Note that the fmtrNoColor is only used when logging to a file
        fmtr = logging.Formatter('\033[36m%(levelname)-5s %(module)s:%(funcName)s():%(lineno)d %(asctime)s\033[0m| %(message)s')
        fmtrNoColor = logging.Formatter('%(levelname)-5s %(module)s:%(funcName)s():%(lineno)d %(asctime)s | %(message)s')

        # The streamhandler is always present
        shandler = logging.StreamHandler(sys.stdout)
        shandler.setFormatter(fmtr)
        logger.addHandler(shandler)

        # the file logger is optional
        if logFile is not None:
            if not os.path.exists(os.path.dirname(logFile)):
                logger.warn("cannot log to logFile=%s: the base directory %s does not exist" % (logFile, os.path.dirname(logFile)))
                
            elif not os.access(os.path.dirname(logFile), os.W_OK):
                # yes, i know the risk in using access()--I just don't care
                logger.warn("cannot log to logFile=%s: cannot write to indicated file due to incorrect permissions" % logFile)

            else:
                fhandler = handlers.WatchedFileHandler(logFile)
                fhandler.setFormatter(fmtrNoColor)
                logger.info("logging to %s in addition to stdout" % logFile)
                logger.addHandler(fhandler)
        
        return logger