Implementing a Python Logger

An Example

This example class builds on the underlying Python logging support.

Module

$ cat Logger.py

import os
import sys
import logging

#==========================================================================

class Logger:
    logger = None
    debug  = False

    @classmethod
    def Info(cls, msg):
        global debug_level, verbose_flg

        if not cls.logger:
            cls.Init()

        cls.logger.info(' ' + msg)

        if cls.debug: sys.stderr.write("[%s::INFO]  %s\n" % (cls.name, msg))

    #----------------------------------------------------------------------

    @classmethod
    def Error(cls, msg):
        global debug_level, verbose_flg

        if not cls.logger:
            cls.Init()

        cls.logger.error(msg)

        if cls.debug: sys.stderr.write("[%s::ERROR]  %s\n" % (cls.name, msg))

    #----------------------------------------------------------------------

    @classmethod
    def Warning(cls, msg):
        global debug_level, verbose_flg

        if not cls.logger:
            cls.Init()

        cls.logger.warning('*****' + msg + '*****')

        if cls.debug: sys.stderr.write("[%s::WARNING]  %s\n" % (cls.name, msg))

    #----------------------------------------------------------------------

    @classmethod
    def Init(cls, name='logger', log_dir='/c/temp', debug=False):
        cls.debug = debug
        cls.name  = name
        cls.pid   = os.getpid()

        if cls.debug: sys.stderr.write("[%s::Init] PID is %d\n" % (cls.name, cls.pid))

        cls.log_file = '%s/%s.log' % (log_dir, name)

        try:
            cls.logger  = logging.getLogger(name)
            cls.hdlr    = logging.FileHandler(cls.log_file)
            cls.fmtr    = logging.Formatter('%(asctime)s %(levelname)s %(message)s')

            cls.hdlr.setFormatter(cls.fmtr)
            cls.logger.addHandler(cls.hdlr)
            cls.logger.setLevel(logging.INFO)

            cls.logger.info("===== Started processing %s" % ('=' * 20))
 
            cls.count = 0
        except IOError, msg:
            sys.stderr.write(cls.log_file + ': cannot open: ' + `msg` + '\n')
            sys.exit(1)

#==========================================================================

Test harness

$ cat tst_logger.py

#!/usr/bin/env python

import flask
import performiq

from performiq import Logger

debug_level  = 0
verbose_flg  = True


print "performiq version [%s]" % performiq.VERSION

Logger.Init(debug=True)

Logger.Info("Testing - Info...")
Logger.Warning("Testing - Warning...")
Logger.Error("Testing - Error...")