How do I get logger to delete existing log file before writing to it again?

python logging filehandler
Paul H picture Paul H · Feb 6, 2014 · Viewed 34.2k times · Source

Using the configuration below, my logfile will be called 'test-debug.log' and it will grow infinitely for everytime I run the script. I just want this logfile to contain the log records from the most recent run of the script. The log should be deleted before starting again.

How do I do that?

logger = logging.getLogger('test') #Create a log with the same name as the script that created it
logger.setLevel('DEBUG')


#Create handlers and set their logging level
filehandler_dbg = logging.FileHandler(logger.name + '-debug.log')
filehandler_dbg.setLevel('DEBUG') 


#Create custom formats of the logrecord fit for both the logfile and the console
streamformatter = logging.Formatter(fmt='%(levelname)s:\t%(threadName)s:\t%(funcName)s:\t\t%(message)s', datefmt='%H:%M:%S') #We only want to see certain parts of the message


#Apply formatters to handlers
filehandler_dbg.setFormatter(streamformatter)


#Add handlers to logger
logger.addHandler(filehandler_dbg)

Answer

dmcc picture dmcc · Feb 6, 2014

Try this:

filehandler_dbg = logging.FileHandler(logger.name + '-debug.log', mode='w')

to open the filename in write mode instead of append mode, clobbering logger.name

More information: logging.FileHandler docs, open() and list of modes

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