title: How to stop a Airflow DAG run from task
body: <p>so I have an airflow DAG task which performs several checks on a file (e.g., if it was already processed in the past) and I want the whole DAG run to stop completely if one of the checks fails. How can I do that?</p>
  
  <p>Basically the checks are done in a python script.</p>
  
  <p>Thx :</p>