monty.logging — monty 4.0.2 documentation

# Source code for monty.logging

    #!/usr/bin/env python

    """
    Logging tools
    """

    import logging
    import datetime
    import functools
    import argparse

    logger = logging.getLogger(__name__)

    def logged(level=logging.DEBUG):
        """
        Useful logging decorator. If a method is logged, the beginning and end of
        the method call will be logged at a pre-specified level.

        Args:
            level: Level to log method at. Defaults to DEBUG.
        """
        def wrap(f):
            _logger = logging.getLogger("{}.{}".format(f.__module__, f.__name__))

            def wrapped_f(*args, **kwargs):
                _logger.log(level, "Called at {} with args = {} and kwargs = {}"
                            .format(datetime.datetime.now(), args, kwargs))
                data = f(*args, **kwargs)
                _logger.log(level, "Done at {} with args = {} and kwargs = {}"
                            .format(datetime.datetime.now(), args, kwargs))
                return data

            return wrapped_f
        return wrap

    def enable_logging(main):
        """
        This decorator is used to decorate main functions.
        It adds the initialization of the logger and an argument parser that allows
        one to select the loglevel.
        Useful if we are writing simple main functions that call libraries where
        the logging module is used

        Args:
            main:
                main function.
        """
        @functools.wraps(main)
        def wrapper(*args, **kwargs):
            parser = argparse.ArgumentParser()

            parser.add_argument(
                '--loglevel', default="ERROR", type=str,
                help="Set the loglevel. Possible values: CRITICAL, ERROR (default),"
                     "WARNING, INFO, DEBUG")

            options = parser.parse_args()

            # loglevel is bound to the string value obtained from the command line
            # argument.
            # Convert to upper case to allow the user to specify --loglevel=DEBUG
            # or --loglevel=debug
            numeric_level = getattr(logging, options.loglevel.upper(), None)
            if not isinstance(numeric_level, int):
                raise ValueError('Invalid log level: %s' % options.loglevel)
            logging.basicConfig(level=numeric_level)

            retcode = main(*args, **kwargs)
            return retcode

        return wrapper