How do I change the default format of log messages in python app engine?

Question

I would like to log the module and classname by default in log messages from my request handlers.

The usual way to do this seems to be to set a custom format string by c

Answer 1

I cooked this up by reading the logging module's __init__.py. I don't know if this is proper, but it seems to work:

import logging

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
                    datefmt='%m-%d %H:%M',
                    )

logging.info('Danger Will Robinson!')
# 03-31 20:00 root         INFO     Danger Will Robinson!
root = logging.getLogger()
hdlr = root.handlers[0]
fmt = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
hdlr.setFormatter(fmt)
logging.info('Danger Will Robinson!')
# root        : INFO     Danger Will Robinson!

Answer 2

I found this to be working for Python 3.6, it will set the logging level / format for all subsequent logging calls, even if logging is called by previous imports.

logging_level = logging.INFO
logging_fmt = "%(levelname)s:%(name)s:%(message)s"   # the default
try:
    root_logger = logging.getLogger()
    root_logger.setLevel(logging_level)
    root_handler = root_logger.handlers[0]
    root_handler.setFormatter(logging.Formatter(logging_fmt))
except IndexError:
    logging.basicConfig(level=logging_level, format=logging_fmt)