nyoungstudios opened a new pull request, #39772:
URL: https://github.com/apache/airflow/pull/39772
## Description
This pull request makes this example DAG work. This DAG uses the XComArg (in
other words, `.output`) from the first task as the input for the
`trigger_dag_id` argument in the `TriggerDagRunOperator`.
```python
# example dag
from airflow.models import DAG
from airflow.operators.python import PythonOperator
from airflow.operators.trigger_dagrun import TriggerDagRunOperator
with DAG(
dag_id="trigger_dag",
description="Tests triggering a dag",
schedule_interval=None,
catchup=False,
) as dag:
get_dag_id = PythonOperator(
task_id="get_dag_id",
python_callable=lambda: "other_dag",
)
trigger_dag = TriggerDagRunOperator(
task_id="trigger_other_dag",
trigger_dag_id=get_dag_id.output,
)
get_dag_id >> trigger_dag
```
## Open Questions
I left the `or` statement in the `get_link` function of the
`TriggerDagRunLink` so that past operator links would still work (ones that
were run before this change). However, if you click the operator link too fast,
before the `self.trigger_dag_id` is pushed to the XCom, it will use the second
value in the `or` statement - which will result in an error message.
Here is the code piece I'm referencing:
https://github.com/nyoungstudios/airflow/blob/0f6499a8ab04617c29d88a2f435197c199fec72d/airflow/operators/trigger_dagrun.py#L79
This is the error message if you click too fast.
## Testing
Tested with both Postgres and SQLite databases.
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