sample_test_dag.py

from datetime import datetime, timedelta
from textwrap import dedent

from airflow import DAG
from airflow.decorators import task

# define default arguments for operators.
default_args = {
    "retries": 1,
    "retry_delay": timedelta(minutes=5),
}

# instantiate a DAG.
with DAG(
    "sample_test_dag",
    default_args=default_args,
    description="A sample test DAG",
    schedule_interval=timedelta(days=1),
    start_date=datetime(2022, 8, 1),
    end_date=datetime(2022, 12, 31),
    catchup=False,
    tags=["sample"],
) as dag:

    # add documentation to a DAG.
    dag.doc_md = __doc__
    dag.doc_md = dedent(
        """This is a sample test DAG."""
    )

    # define the task 1.
    @task
    def get_version() -> str:
        import sys
        print(f"print: {sys.version}")
        return sys.version

    get_version.doc_md = dedent(
        """This is a sample python task: get_version."""
    )

    # define the task 2.
    @task
    def print_version(ver: str) -> None:
        print(f"receive: {ver}")
        return

    print_version.doc_md = dedent(
        """This is a sample python task: print_version."""
    )

    # setting up dependencies.
    version = get_version()
    print_version(version)