Source code for airflow.example_dags.example_short_circuit_decorator
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"""Example DAG demonstrating the usage of the `@task.short_circuit()` TaskFlow decorator."""
from __future__ import annotations
import pendulum
from airflow.decorators import dag, task
from airflow.models.baseoperator import chain
from airflow.operators.empty import EmptyOperator
from airflow.utils.trigger_rule import TriggerRule
@dag(schedule=None, start_date=pendulum.datetime(2021, 1, 1, tz="UTC"), catchup=False, tags=["example"])
[docs]def example_short_circuit_decorator():
# [START howto_operator_short_circuit]
@task.short_circuit()
def check_condition(condition):
return condition
ds_true = [EmptyOperator(task_id=f"true_{i}") for i in [1, 2]]
ds_false = [EmptyOperator(task_id=f"false_{i}") for i in [1, 2]]
condition_is_true = check_condition.override(task_id="condition_is_true")(condition=True)
condition_is_false = check_condition.override(task_id="condition_is_false")(condition=False)
chain(condition_is_true, *ds_true)
chain(condition_is_false, *ds_false)
# [END howto_operator_short_circuit]
# [START howto_operator_short_circuit_trigger_rules]
[task_1, task_2, task_3, task_4, task_5, task_6] = [
EmptyOperator(task_id=f"task_{i}") for i in range(1, 7)
]
task_7 = EmptyOperator(task_id="task_7", trigger_rule=TriggerRule.ALL_DONE)
short_circuit = check_condition.override(task_id="short_circuit", ignore_downstream_trigger_rules=False)(
condition=False
)
chain(task_1, [task_2, short_circuit], [task_3, task_4], [task_5, task_6], task_7)
# [END howto_operator_short_circuit_trigger_rules]
[docs]example_dag = example_short_circuit_decorator()