Python日志记录重复输出

Question

I've been studying python logging since a few days and I'm testing it today at work. I'm testing the following code:

import inspect
import logging

def customLogger(FileHandlerlogLevel, ConsoleHandlerLogLevel, file_path_and_name):
    '''
    - logLevel input values:  DEBUG, INFO, WARNING, ERROR, CRITICAL
    '''

    # Gets the name of the class / method from where this method is called
    loggerName = inspect.stack()[1][3]

    logger = logging.getLogger(loggerName)

    logger.setLevel(logging.DEBUG)

    fileHandler = logging.FileHandler(file_path_and_name, mode="w")
    fileHandler.setLevel(FileHandlerlogLevel)

    formatter = logging.Formatter('%(name)s - %(lineno)d - %(asctime)s - %(levelname)s - %(message)s',
                                  datefmt="%m/%d/%Y %I:%M:%S %p")
    fileHandler.setFormatter(formatter)

    logger.addHandler(fileHandler)    

    stream_handler = logging.StreamHandler()
    stream_handler.setLevel(ConsoleHandlerLogLevel)
    stream_handler.setFormatter(formatter)
    logger.addHandler(stream_handler)


    return logger

test_logger = customLogger(logging.DEBUG,  logging.DEBUG,  "test_loggerv01.log")
test_logger.info("test 01")

So basically I have two handlers for a given logger. When I run the script the first time, this is what the console (Spyder) shows:

In [1]: runfile('C:/Users/aardem/Python_AA/AB/Corproates_Prj/custom_logger_andrea_v02.py', wdir='C:/Users/aardem/Python_AA/AB/Corproates_Prj')
<module> - 36 - 07/19/2018 06:32:22 PM - INFO - test 01

So far so good. Then, I change the info message to "test 02" (last line of my code), save and re-run the script. Now, the console shows the following:

In [2]: runfile('C:/Users/aardem/Python_AA/AB/Corproates_Prj/custom_logger_andrea_v02.py', wdir='C:/Users/aardem/Python_AA/AB/Corproates_Prj')
<module> - 36 - 07/19/2018 06:32:34 PM - INFO - test 02
<module> - 36 - 07/19/2018 06:32:34 PM - INFO - test 02

Again, if I change the last line of my script to:

test_logger.info("test 03")

then save and re-run the script, this is the new console output:

In [3]: runfile('C:/Users/aardem/Python_AA/AB/Corproates_Prj/custom_logger_andrea_v02.py', wdir='C:/Users/aardem/Python_AA/AB/Corproates_Prj')
<module> - 37 - 07/19/2018 06:38:20 PM - INFO - test 03
<module> - 37 - 07/19/2018 06:38:20 PM - INFO - test 03
<module> - 37 - 07/19/2018 06:38:20 PM - INFO - test 03

Can somebody help me with this unexpected problem? The same problem happens with the data saved inside the file "test_loggerv01.log". Thank you

Answer 1

Every time you run that file with runfile in the same IPython session, you're adding more and more handlers to the same logger. The old handlers don't go away.

All those duplicate handlers will handle that logger's log records, resulting in duplicate log handling.