from airflow import DAG
from datetime import datetime
from airflow.operators.bash_operator import BashOperator

seven_days_ago = datetime.combine(datetime.today() - timedelta(7),
                                  datetime.min.time())

default_args = {
    'owner': 'sumit',
    'start_date': seven_days_ago,
    'depends_on_past': True
}

dag = DAG('scheduler_issue', default_args=default_args, schedule_interval='30 * * * *')

t1 = BashOperator(
    task_id='task_1',
    bash_command='echo 1',
    dag=dag)