如何从 airflow 中 python 运算符的上一个任务中选择返回值

Question

while trying to capture the output of a task of python operator into a variable getting error. Any suggestion pls

with DAG(
        dag_id="test_dag",
        start_date=datetime(2022, 1, 24),
        schedule_interval=None,
        render_template_as_native_obj=True,
        default_args={},
        params={
            "param2": "arya2@gmail.com",
            "sourcedir": ['/home/arya/'],
            "timenum": 0
        },
        catchup=False
) as dag:

    pythondefination = PythonOperator(
                    task_id=f"pythondefinationfunc",
                    python_callable=pythondefination,
                    provide_context=True
                    )

    def valuecapture(**kwargs):
        ti  = kwargs['ti']
        timeinfo = ti.xcom_pull(task_ids='pythondefinationfunc')
        return timeinfo
        
        
    **Error: KeyError: 'ti'

Answer 1

To access the return value from the previous task, you can read it from xcom, but the read should be in an airflow operator in order to access the run context:

bash_task = BashOperator(
    task_id="read_python_func_return_value",
    bash_command="echo {{ti.xcom_pull(task_ids='pythondefinationfunc')}}",
)