stamped-filehandler.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import logging
import logging.handlers
import freezegun
import time
import os


class StampedFileHandler(logging.FileHandler):
    def __init__(self, filename, suffix='%Y%m%d', mode='a', encoding=None, delay=False):
        self.suffix = suffix
        self.origFilename = os.path.abspath(filename)
        stamped_filename = self._stamped_filename()
        super().__init__(stamped_filename, mode, encoding, delay)

    def _stamped_filename(self):
        return '%s.%s' % (self.origFilename, time.strftime(self.suffix, time.localtime()))

    def emit(self, record):
        stamped_filename = self._stamped_filename()
        if self.baseFilename != stamped_filename:
            self.baseFilename = stamped_filename
            self.close()
        super().emit(record)


def main():
    with freezegun.freeze_time('2017-12-31 14:59:58') as freezer:
        logger = logging.getLogger(__name__)
        logger.setLevel(logging.INFO)
        formatter = logging.Formatter('%(asctime)s (%(name)-9s) [%(levelname)-7s] %(message)s')

        file_handler = StampedFileHandler(
            '/tmp/test.log',
            )
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)

        for i in range(5):
            logger.info("Hello, %d", i)
            freezer.tick()


if __name__ == '__main__':
    main()