#dags/latest_only_with_trigger.py
import datetime as dt

from airflow.models import DAG
from airflow.operators.dummy_operator import DummyOperator
from airflow.utils.trigger_rule import TriggerRule


dag = DAG(
dag_id='latest_only_with_trigger',
schedule_interval=dt.timedelta(minutes=5),
start_date=dt.datetime(2019, 2, 20),
)

task1 = DummyOperator(task_id='task1', dag=dag)
task2 = DummyOperator(task_id='task2', dag=dag,
                      trigger_rule=TriggerRule.all_success)
task3 = DummyOperator(task_id='task3', dag=dag
                      trigger_rule=TriggerRule.all_failed)

###### ORCHESTRATION ###
task2.set_upstream(task1)
task3.set_upstream(task1)