Python 3.10. TimedRotatingFileHandler writes in different file

Question

I'm trying to use the logging module in python 3.10 to create daily log files. Here is how I proceed:

test.py

cwd = os.path.dirname(os.path.realpath(__file__))

# configure logger
logging.config.fileConfig(Path(cwd, "logging.ini"))
logger = logging.getLogger("test")

for i in range(10):
    logger.log(logging.INFO, "bonjour")
    time.sleep(1)

classCustomLogging.py

class CustomTimedRotatingFileHandler(logging.handlers.
                                     TimedRotatingFileHandler):


    def __init__(self, prefix, when, backupCount):

        cwd = os.path.dirname(os.path.realpath(__file__))
        self.dir_log = Path(cwd, "Logs")

        file_path = Path(self.dir_log, f"{prefix}.log")
        log_files = Path(self.dir_log).glob("**/*.log")

        logging.handlers\
               .TimedRotatingFileHandler.__init__(self,
                                                  file_path,
                                                  when=when,
                                                  backupCount=backupCount)

and logging.ini

[loggers]
keys=root, test

[handlers]
keys=customLogging_info, consoleHandler

[formatters]
keys=main

[handler_consoleHandler]
class=StreamHandler
level=CRITICAL
formatter=main
args=(sys.stdout,)

[logger_test]
level=DEBUG
handlers=customLogging_info
qualname=test

[logger_root]
handlers=consoleHandler

[handler_customLogging_info]
level=DEBUG
class=classCustomLogging.CustomTimedRotatingFileHandler
formatter=main
args = ("Debug","S", 2)

[formatter_main]
class=classCustomLogging.CustomFormatter

While testing I'm excepting to have only 2 files which are rotating every seconds but instead I'm getting:

Debug.log
Debug.log.2022-02-11_17-46-08
Debug.log.2022-02-11_17-46-09

And in the Debug.log a new line is written every seconds but not appended, like if whatever happens the log will also be written in this file anyway. The log in the timestamped file seems correct tough. Is this a normal behavior? Or where is the error?

Hoping I was clear enough.

Answer 1

I found a way to achieve my goal by re-implementing some of the method based on this answer

class CustomTimedRotatingFileHandler(logging.handlers.
                                 TimedRotatingFileHandler):

def __init__(self, prefix, when, backupCount):

    """
    :param prefix: string, prefix for log file
    :param when: frequency of rotation
    :param backUpCount: int, number o file to keep
    """

    if when == "S":
        suffix = "%Y-%m-%d_%H-%M-%S"
    elif when == "M":
        suffix = "%Y-%m-%d_%H-%M"
    elif when == "H":
        suffix = "%Y-%m-%d_%H"
    elif when == "D" or when == "MIDNIGHT":
        suffix = "%Y-%m-%d"
    elif when.startswith("W"):
        suffix = "%Y-%m-%d"
    else:
        raise ValueError("Invalid rollover interval specified: %s"
                         % self.when)

    cwd = os.path.dirname(os.path.realpath(__file__))
    self.dir_log = Path(cwd, "Logs")
    self.prefix  = prefix
    self.ext = ".log"

    filename = Path(self.dir_log, f"{self.prefix}{time.strftime(suffix)}{self.ext}")
    log_files =self.dir_log.rglob("*.log")

    logging.handlers\
           .TimedRotatingFileHandler.__init__(self,
                                              filename,
                                              when=when,
                                              backupCount=backupCount)


def getFilesToDelete(self):

    """
    Re-implement base method
    """

    fileNames = os.listdir(self.dir_log)
    result = []
    plen = len(self.prefix)
    for fileName in fileNames:
        extlen = len(self.ext)
        if fileName[:plen] == self.prefix:
            suffix = fileName[plen:-extlen]
            if self.extMatch.match(suffix):
                result.append(os.path.join(self.dir_log, fileName))
    result.sort()

    if len(result) < self.backupCount:
        result = []
    else:
        result = result[:len(result) - self.backupCount]

    return result


def doRollover(self):

    """
    Re-implement base method
    """

    self.stream.close()

    # get the time that this sequence started at and make it a TimeTuple
    t = self.rolloverAt - self.interval

    self.baseFilename = Path(self.dir_log, f"{self.prefix}{time.strftime(self.suffix)}{self.ext}")

    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
    if self.backupCount > 0:
        for s in self.getFilesToDelete():
            os.remove(s)