How to log from Python Luigi

Inside any of the Task class methods, you can do:

class Agg(luigi.Task):
  _date = luigi.DateParameter()

  def output(self):
    return luigi.LocalTarget("file_%.txt" % self._date)

  def run(self):
    # Use the luigi-interface to log to console
    logger = logging.getLogger('luigi-interface')
    logger.info("Running --> Agg.Task")