Source code for airflow.example_dags.example_branch_operator_decorator
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"""Example DAG demonstrating the usage of the ``@task.branch`` TaskFlow API decorator."""
from __future__ import annotations
import random
import pendulum
from airflow import DAG
from airflow.decorators import task
from airflow.operators.empty import EmptyOperator
from airflow.utils.edgemodifier import Label
from airflow.utils.trigger_rule import TriggerRule
with DAG(
dag_id="example_branch_python_operator_decorator",
start_date=pendulum.datetime(2021, 1, 1, tz="UTC"),
catchup=False,
schedule="@daily",
tags=["example", "example2"],
) as dag:
[docs] run_this_first = EmptyOperator(task_id="run_this_first")
options = ["branch_a", "branch_b", "branch_c", "branch_d"]
@task.branch(task_id="branching")
def random_choice(choices: list[str]) -> str:
return random.choice(choices)
random_choice_instance = random_choice(choices=options)
run_this_first >> random_choice_instance
join = EmptyOperator(task_id="join", trigger_rule=TriggerRule.NONE_FAILED_MIN_ONE_SUCCESS)
for option in options:
t = EmptyOperator(task_id=option)
empty_follow = EmptyOperator(task_id="follow_" + option)
# Label is optional here, but it can help identify more complex branches
random_choice_instance >> Label(option) >> t >> empty_follow >> join