Log Log

A log consists of four parts

    1. logger logger
       program, a logger records log information during program execution
       log information, may be used to monitor the running state of operation and maintenance.

    Log Handler processor 2.
       When the log information recorded by the recording, the processor needs to process.
       StreamHandler generally used in console output
       may also be used to HTTPHandler server log files to the log (Log The Flume Distributed Services)
       course, the use FileHandler writes log information to a file
       
       used in the processor:
            stream processor: StreamHandler
            file handler: FileHandler
            network request processor: HTTPHandler uploads the log information to a log server (Flask / Flume)
            mail box processor: SMTPHandler

    3. formatting formatter log
       records log records, according to a certain format to the processor
       format comprising:
           the asctime time of occurrence log
           pathname
           filename
           funcName
           Process Process ID
           Thread thread ID
           Message log message
           name levelname log level
           line number occur lineno log
           records the name name filter

    4. Filter log filter
       filters recorder for recording information



two, log level
     in the logging module, points 6 levels
     - cRITICAL 50 serious errors
     - eRROR 40 error
     - wARNING 30 wARNING
     - INFO 20 general message
     - dEBUG 10 debug
     - nOSET 0 default is not set

three step application
    . 1) Import the logging
       Import TimeRotatingFileHandler, the HTTPHandler, SMTPHandler

    2) creating or get the logger default name for the root logger
       = logging.getLogger Logger ( 'django.request')

       # Set logger level
       Logger.setLevel (logging.info)

       root_logger logging.getLogger = ()

    . 3) to create formatter formatting objects, and add to the processor
                            Time level
       F = the Formatter (FMT = '% (the asctime) S% (levelname) S:% (Message) S',
                     datefmt = '')

    . 4) creating processor Handler
       Handler The StreamHandler = ()
       handler.setFormatter (F) set # formatting processor

       level # setting processor
       handler.setLevel (logging.info)

    . 5) to add processors to a logger object
       logger.addHandler (Handler)

    . 6) at a certain feature point of the program, by logging is to record important information
       logger.info ( 'xxxx') # level of information is recorded iNFO
       logger.error ( 'xxxx') # class information is recorded ERROR
       logger.debug ( '.....') # level information is recorded DEBUG