inclusion/exclusion filter implementation

filters.py

#!/usr/bin/env python

import fnmatch

def inclusion_exclusion_filter(include=(), exclude=()):
    """Create an inclusion exclusion filter

    :param include: sequence of glob patterns to include
    :param exclude: sequence of glob patterns to exclude
    :returns: function(name) that filters strings based on the provided filters
    """
    def apply_filter(name):
        """Apply a filter to ``name``

        If inclusion patterns are specified and no patterns are
        matched, the value will be excluded and this function
        returns ``True``.

        If no inclusion patterns are specified all values will
        be included unless some exclusion pattern is matched.

        If an exclusion pattern is matched, the matched pattern
        will be returned as true value.

        If no exclusion patterns were matched, ``False`` is returned
        indicating the value was not excluded

        :param name: string value to filter
        :returns: true value if filtered, False otherwise
        """
        if include:
            for pattern in include:
                if fnmatch.fnmatch(name, pattern):
                    break
            else:
                # no exclusion patterns matched
                return True
        for pattern in exclude:
            if fnmatch.fnmatch(name, pattern):
                return pattern
        return False
    return apply_filter

if __name__ == '__main__':
    pred = inclusion_exclusion_filter(include=['mysql.*'], exclude=['mysql.proc*'])
    assert pred('mysql.user') is False
    assert pred('mysql.proc') == 'mysql.proc*'