如何获取运行id并将其放入Airflow中的变量中

from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from airflow.utils.dates import days_ago
from airflow.models import Variable
from datetime import datetime

def set_execution_date(**context):
    execution_date = context['execution_date']
    Variable.set("execution_date", str(execution_date))

default_args = {
    'owner': 'airflow',
    'start_date': days_ago(1),
}

dag = DAG(
    'set_execution_date_dag',
    default_args=default_args,
    schedule_interval='@daily',
)

set_date_task = PythonOperator(
    task_id='set_execution_date',
    python_callable=set_execution_date,
    provide_context=True,
    dag=dag,
)

set_date_task

# 检查变量是否存在
if Variable.get("execution_date") is None:
    Variable.set("execution_date", str(execution_date))
else:
    print("Variable already exists.")