from datetime import datetime, timedelta
from airflow import DAG
from airflow.operators.bash_operator import BashOperator
from airflow.operators.dummy_operator import DummyOperator
from airflow.operators.python_operator import PythonOperator

default_args = {
    'owner': 'airflow',
    'start_date': datetime(2022, 1, 1),
    'depends_on_past': False,
    'retries': 1,
    'retry_delay': timedelta(minutes=5),
}

dag = DAG(
    'my_dag',
    default_args=default_args,
    schedule_interval='@weekly',
)

def set_start_date():
    # 使用datetime计算出每周开始日期
    today = datetime.today()
    start_date = (today - timedelta(days=today.weekday()))
    return start_date

start_operator = PythonOperator(
    task_id='set_start_date',
    python_callable=set_start_date,
    dag=dag,
)

dummy_operator = DummyOperator(
    task_id='dummy_operator',
    dag=dag,
)

bash_operator = BashOperator(
    task_id='bash_operator',
    bash_command='echo "Hello, World!"',
    dag=dag,
)

start_operator >> dummy_operator >> bash_operator