TimedRotatingFileHandler Changing File Name?

Question

I am trying to implement the python logging handler TimedRotatingFileHandler.

When it rolls over to midnight it appends the current day in the form YYYY-MM-DD.

LOGGING_MSG_FORMAT  = '%(name)-14s > [%(levelname)s] [%(asctime)s] : %(message)s'
LOGGING_DATE_FORMAT = '%Y-%m-%d %H:%M:%S'

logging.basicConfig(
            level=logging.DEBUG,
            format=LOGGING_MSG_FORMAT,
            datefmt=LOGGING_DATE_FORMAT
            )
root_logger = logging.getLogger('')
logger = logging.handlers.TimedRotatingFileHandler("C:\\logs\\Rotate_Test",'midnight',1)
root_logger.addHandler(logger)
while True:
    daemon_logger = logging.getLogger('TEST')
    daemon_logger.info("SDFKLDSKLFFJKLSDD")
    time.sleep(60)

The first log file created is named Rotate_Test, then once it rolls over to the next day it changes the file name to Rotate_Test.YYYY-MM-DD where YYYY-MM-DD is the current day.

How can I change how it alters the filename?

Answer 1

"How can i change how it alters the filename?"

Since it isn't documented, I elected to read the source. This is what I concluded from reading the source of logging/handlers.py

handler = logging.handlers.TimedRotatingFileHandler("C:\\isis_ops\\logs\\Rotate_Test",'midnight',1) handler.suffix = "%Y-%m-%d" # or anything else that strftime will allow root_logger.addHandler(handler) 

The suffix is the formatting string.

Answer 2

You can do this by changing the log suffix as suggested above but you will also need to change the extMatch variable to match the suffix for it to find rotated files:

handler.suffix = "%Y%m%d"
handler.extMatch = re.compile(r"^\d{8}$")

Answer 3

There is another approach to this problem: for example, I need to rotate logs on a daily basis but they must be named with a suffix in the %m%d%Y format...

So I wrote a TimedRotatingFileHandler remix!

try:
    import codecs
except ImportError:
    codecs = None
import logging.handlers
import time
import os

class MyTimedRotatingFileHandler(logging.handlers.TimedRotatingFileHandler):
  def __init__(self,dir_log):
   self.dir_log = dir_log
   filename =  self.dir_log+time.strftime("%m%d%Y")+".txt" #dir_log here MUST be with os.sep on the end
   logging.handlers.TimedRotatingFileHandler.__init__(self,filename, when='midnight', interval=1, backupCount=0, encoding=None)
  def doRollover(self):
   """
   TimedRotatingFileHandler remix - rotates logs on daily basis, and filename of current logfile is time.strftime("%m%d%Y")+".txt" always
   """ 
   self.stream.close()
   # get the time that this sequence started at and make it a TimeTuple
   t = self.rolloverAt - self.interval
   timeTuple = time.localtime(t)
   self.baseFilename = self.dir_log+time.strftime("%m%d%Y")+".txt"
   if self.encoding:
     self.stream = codecs.open(self.baseFilename, 'w', self.encoding)
   else:
     self.stream = open(self.baseFilename, 'w')
   self.rolloverAt = self.rolloverAt + self.interval