How to set dependencies between DAGs in Airflow?
You can achieve this behavior using an operator called ExternalTaskSensor.Your task (B1) in DAG(B) will be scheduled and wait for a success on task (A2) in DAG(A)
It looks like a TriggerDagRunOperator can be used as well, and you can use a python callable to add some logic. As explained here : https://www.linkedin.com/pulse/airflow-lesson-1-triggerdagrunoperator-siddharth-anand
When cross-DAG dependency is needed, there are often two requirements:
Task
B1on DAGBneeds to run after taskA1on DAGAis done. This can be achieved usingExternalTaskSensoras others have mentioned:B1 = ExternalTaskSensor(task_id="B1", external_dag_id='A', external_task_id='A1', mode="reschedule")When user clears task
A1on DAGA, we want Airflow to clear taskB1on DAGBto let it re-run. This can be achieved usingExternalTaskMarker(since Airflow v1.10.8).A1 = ExternalTaskMarker(task_id="A1", external_dag_id="B", external_task_id="B1")
Please see the doc about cross-DAG dependencies for more details: https://airflow.apache.org/docs/stable/howto/operator/external.html