Source code for airflow.providers.docker.example_dags.tutorial_taskflow_api_etl_docker_virtualenv

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# [START tutorial]
# [START import_module]
from datetime import datetime

from airflow.decorators import dag, task

# [END import_module]


# [START instantiate_dag]
@dag(schedule_interval=None, start_date=datetime(2021, 1, 1), catchup=False, tags=['example'])
def tutorial_taskflow_api_etl_docker_virtualenv():
    """
    ### TaskFlow API Tutorial Documentation
    This is a simple ETL data pipeline example which demonstrates the use of
    the TaskFlow API using three simple tasks for Extract, Transform, and Load.
    Documentation that goes along with the Airflow TaskFlow API tutorial is
    located
    [here](https://airflow.apache.org/docs/apache-airflow/stable/tutorial_taskflow_api.html)
    """
    # [END instantiate_dag]

    # [START extract_virtualenv]
    @task.virtualenv(
        use_dill=True,
        system_site_packages=False,
        requirements=['funcsigs'],
    )
    def extract():
        """
        #### Extract task
        A simple Extract task to get data ready for the rest of the data
        pipeline. In this case, getting data is simulated by reading from a
        hardcoded JSON string.
        """
        import json

        data_string = '{"1001": 301.27, "1002": 433.21, "1003": 502.22}'

        order_data_dict = json.loads(data_string)
        return order_data_dict

    # [END extract_virtualenv]

    # [START transform_docker]
    @task.docker(image='python:3.9-slim-buster', multiple_outputs=True)
    def transform(order_data_dict: dict):
        """
        #### Transform task
        A simple Transform task which takes in the collection of order data and
        computes the total order value.
        """
        total_order_value = 0

        for value in order_data_dict.values():
            total_order_value += value

        return {"total_order_value": total_order_value}

    # [END transform_docker]

    # [START load]
    @task()
    def load(total_order_value: float):
        """
        #### Load task
        A simple Load task which takes in the result of the Transform task and
        instead of saving it to end user review, just prints it out.
        """

        print(f"Total order value is: {total_order_value:.2f}")

    # [END load]

    # [START main_flow]
    order_data = extract()
    order_summary = transform(order_data)
    load(order_summary["total_order_value"])
    # [END main_flow]


# The try/except here is because Airflow versions less than 2.2.0 doesn't support
# @task.docker decorator and we use this dag in CI test. Thus, in order not to
# break the CI test, we added this try/except here.
try:
    # [START dag_invocation]
    tutorial_etl_dag = tutorial_taskflow_api_etl_docker_virtualenv()
    # [END dag_invocation]
except AttributeError:
    pass

# [END tutorial]

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