How to get the current python logging config?

user_5953635 0
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I am using the python logging library to configure my loggers with an input dict, like this:

logging.config.dictConfig(config)

I have a special function that should use a new function, and then switch back to the original logger at the end of the function. The original logger can vary, so I do not want to hardcode it. Some psuedocode to describe what I want:

def switch_logger_for_this_code():
    old_logging_config = logger.get_current_logging_config(). # This is what I want to accomplish

    logging.config.dictConfig(new_logging_config)
    logging.info('This log goes to the new config!')
    logging.config.dictConfig(old_logging_config)
    logging.info('This log goes to the old config!')
    return

Is this possible to do with the logging library?

python-logging python
2 Answers

I don't believe there is any built in way of retrieving the config of an initialized logger and storing it into a variable. I'm not sure if this would work for your project, but have you considered just creating a temporary logger object for use within the function's scope?

import logging
from sys import stdout


def switch_logger_for_this_code(msg) -> None:
    # Create logging.Formatter for output customization
    formatter = logging.Formatter(
        fmt="[%(asctime)s.%(msecs)d] %(message)s",
        datefmt="%Y/%m/%d %H:%M:%S"
    )

    handler = logging.StreamHandler(stdout)  # Create output handler
    handler.setLevel(logging.ERROR)  # Specify logging level
    handler.setFormatter(formatter)  # Apply desired format

    temp_log = logging.getLogger("temp")  # Get new or existing Logger
    temp_log.addHandler(handler)  # Add output handler
    temp_log.error(msg)  # Log the message


switch_logger_for_this_code("hello world")  # Log 'hello world'

# Which would output the following
# [2020/10/20 15:09:18.548] hello world

The main idea behind this approach is that the original logger object won't be modified, but you can still use the temporary logger to log what you had originally intended in your desired format.

user_111684830

I just looked through the source code for the logging module, and I don't see any way to get at the internal configuration, which starts as the passed in configuration, but can then be modified by other calls to the logging system.

user_76314800
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