rename a log file in python using a logging module

Question

I need to rename a logging file but continue logging to it afterwards. I'm running Python 3.x and using a logging module to create logs.

logger = logging.getLogger(r'mylogger')
handler = logging.FileHandler(r'mylog.txt', mode = r'w')
logger.addHandler(handler)
logger.info(r'msg 1')
logger.info(r'msg 2')

handler.renameFile(r'my_newlog.txt')  # <--- Is something like this possible?

logger.info(r'msg 3')

Does anyone know if something like this is possible? If no, how would I go about doing it? One idea that I had was to close the file (handler.close()), remove the handler from the logger, rename the old file, create a new handler with the new file name and add it to the logger. The issue however is that I would need to create a completely identical handler, i.e it would need to have the same attributes as the old one (with exception of the file name of course). Is there a simple way to store old attributes and then use them to set the attributes of the new handler?

Any help is appreciated.

Answer 1

Late the party, but I ran into this problem as well and here's how I've (tentatively) solved it. Needs more testing though.

Note in my case, I do have access to the previous handler, so I just wound up using the same handler configuration I used earlier. I agree a FileHandler.'rename_file()' method would be great. One could likely be cooked up by sub-classing FileHandler(), but that's an exercise for another day.

#!/usr/bin/env python3

import os
import logging

logger_name1 = 'my_log.txt'
logger_name2 = 'my_new_log.txt'

logger = logging.getLogger('mylogger')
logger.level = logging.INFO
handler = logging.FileHandler(logger_name1, mode='w')
logger.addHandler(handler)
logger.info('msg 1')
logger.info('msg 2')

# handler.renameFile('my_newlog.txt')  # <--- Is something like this possible?

logger.removeHandler(handler)

# Rename the logfile on disk
os.rename(logger_name1, logger_name2)

# New handler using new filename.  Note the 'append' flag
new_handler = logging.FileHandler(logger_name2, mode='a')
logger.addHandler(new_handler)

# Try out the new logfile
logger.info('msg 3')