logging.handlers.RotatingFileHandler is inelegant and prone to failure. Inelegant in that it simply appends ".NN" to the filename, resulting in the filetype suffix being lost in the name. Prone to failure because it does not have sufficient mitigation strategies in the case of accidentally locked files. > Traceback (most recent call last): > File "c:\PyPy27\lib-python\2.7\logging\handlers.py", line 78, in emit > self.doRollover() > File "c:\PyPy27\lib-python\2.7\logging\handlers.py", line 141, in > doRollover > os.rename(self.baseFilename, dfn) > WindowsError: [Error 32] The process cannot access the file because it > is being used by another process Make a new log writer that takes all the same parameters and writes logs in <filename><date>.<filetype> format to mitigate the locked file problem. And should the locked file problem happen, move to a new file.