Python Logging log rotation file does not delete the issue

Objective

Recently in the Python Project code that maintains the project, the project uses the Python log module logging, which sets the number of saved logs, but does not take effect, and cleans up the data periodically through contab.

Analysis

The project uses the logging Timedrotatingfilehandler:

1 #!/user/bin/env python2 #-*-coding:utf-8-*-3 4 ImportLogging5  fromLogging.handlersImportTimedrotatingfilehandler6Log =Logging.getlogger ()7file_name ="./test.log"8Logformatter = logging. Formatter ('% (asctime) s [% (LevelName) s]|% ( Message) s')9LogHandle = Timedrotatingfilehandler (file_name,'Midnight', 1, 2)Ten Loghandle.setformatter (logformatter) OneLoghandle.suffix ='%y%m%d' A Log.addhandler (LogHandle) - Log.setlevel (logging. DEBUG) -  theLog.debug ("Init successful")

Refer to the official documentation for Python logging:

Https://docs.python.org/2/library/logging.html

Look at the Getting started instance to see the use of time-rotated content:

1 ImportLogging2 3 #Create Logger4Logger = Logging.getlogger ('Simple_example')5 Logger.setlevel (logging. DEBUG)6 7 #Create console handler and set level to debug8CH =logging. Streamhandler ()9 Ch.setlevel (logging. DEBUG)Ten  One #Create Formatter AFormatter = logging. Formatter ('% (asctime) s-% (name) s-% (levelname) s-% (message) s') -  - #Add formatter to CH the Ch.setformatter (Formatter) -  - #Add ch to logger - logger.addhandler (CH) +  - #' Application ' code +Logger.debug ('Debug Message')

Looking down, there is nothing wrong with the place.

Then look at the logging code, find the Timedrotatingfilehandler related content, which deletes the contents of the expired log:

logging/handlers.py

    defGetfilestodelete (self):"""determine the files to delete is rolling over.        More specific than the earlier method, which just used Glob.glob (). """DirName, BaseName=os.path.split (self.basefilename) fileNames=Os.listdir (dirName) result=[] Prefix= BaseName +"."Plen=len (prefix) forFileNameinchFileNames:iffilename[:p len] = =Prefix:suffix=Filename[plen:]ifself.extMatch.match (suffix): result.append (Os.path.join (DirName, FileName)) Result.sort () ifLen (Result) <Self.backupCount:result= []        Else: Result= Result[:len (Result)-Self.backupcount]returnResult

The principle of rotation is to find the log directory, matching the suffix suffix of the file, added to the delete list, if the specified number is added to the list to be deleted, and then look at the principle of matching:

        elif ' D ' or ' Midnight ' :             # One day             " %y-%m-%d " = R"^\d{4}-\d{2}-\d{2}$"             

Exmatch is a regular match, the format is-separated by the time, and we set ourselves a new suffix without-separating:

Loghandle.suffix = '%y%m%d '

This will not find the file you want to delete and will not delete the associated log.

Summarize

1. The encapsulated library, try to use the Open interface, do not arbitrarily modify the internal variables;

2. There is a problem with the code, you can not find the reason, you may look at the code.

Python Logging log rotation file does not delete the issue