airflow/utils/dag_processing.py
def _heartbeat_manager(self):
        """
        Heartbeat DAG file processor and start it if it is not alive.
        :return:
        """
        if self._process and not self._process.is_alive() and not self.done:
            self.start()
def _heartbeat_manager(self):
        """
        Heartbeat DAG file processor and start it if it is not alive.
        :return:
        """
        if self._process and not self._process.is_alive() and not self.done:
            self.start()
Heartbeat DAG file processor and start it if it is not alive.
        :return: