How can I access @dag decorator parameters within tasks

Question

I try to use Apache Airflow's @dag decorator with parameters (params argument) to be able to run same instructions for different configurations, but can't find information on how to access these params' values within the code.

Here is the sample:

@dag(
        dag_id='DAG_ID',
        start_date=datetime(2023, 6, 1),
        params={
            'id': 'ID_A'
        }
)
def main(**kwargs):
    print(...) # want to print 'ID_A' here

I want to print 'ID_A' value in the function and later pass it as an argument to one of the DAG tasks, how can I do it?

Answer 1

You can use Jinja Template,

also, you can get the dag_run and find it inside "conf" property.

from datetime import datetime

from airflow.decorators import task, dag

id_param = "{{ params.id }}"


@dag(
    dag_id='DAG_ID',
    start_date=datetime(2023, 6, 1),
    params={
        'id': 'ID_A'
    }
)
def my_dag():

    @task
    def print_value(value):
        print(value)

    @task
    def get_conf():
        context = get_current_context()
        dag_run: DagRun = context["dag_run"]
        print(dag_run.conf.get("id"))

    print_value(id_param) >> get_conf()


my_dag()