A target that causes luigi to run again after a file reaches a maximum age

targets.py

class RecentlyModifiedLocalTarget(luigi.LocalTarget):
    """
    The local file must have been recently enough modified to "exist", driving luigi's DAG
    """

    def __init__(self, *args, **kwargs):
        """
        Extract an optional maxage parameter
        """
        maxage = kwargs.pop('maxage', None)
        super(RecentlyModifiedLocalTarget, self).__init__(*args, **kwargs)

        # Process the maximum age for units of days, weeks, and months
        if maxage is None:
            maxage = 5*24*60*60
        if isinstance(maxage, str):
            if maxage.endswith('d'):
                maxage = int(maxage[:-1]) * 24*60*60
            elif maxage.endswith('w'):
                maxage = int(maxage[:-1]) * 7*24*60*60
            elif maxage.endswith('m'):
                maxage = int(maxage[:-1]) * 30*24*60*60
            else:
                maxage = int(maxage)
        self.maxage = maxage

    def exists(self):
        """
        If the file exists, stat it
        If its age relative to now is more that the maxage, then it doesn't exist

        :return: True or False
        """
        exists = super(RecentlyModifiedLocalTarget, self).exists()
        if exists:
            finfo = os.stat(self.path)
            if time.time() - finfo.st_mtime > self.maxage:
                return False
        return exists