Creating a basic DAG file in Apache Airflow - Try It Yourself

Creating a basic DAG file

📖 Scenario: You are working as a data engineer. You need to create a simple workflow to run tasks in Apache Airflow. This workflow is called a DAG (Directed Acyclic Graph). It helps you schedule and organize tasks.

🎯 Goal: Build a basic Airflow DAG file that defines a simple workflow with one task. This task will print a message when it runs.

📋 What You'll Learn

Create a DAG object with a specific dag_id and start_date.

Define a Python function that prints a message.

Create a PythonOperator to run the function.

Set the task in the DAG.

Print the DAG object at the end.

💡 Why This Matters

🌍 Real World

Airflow DAGs are used to automate and schedule workflows in data pipelines and other automated tasks.

💼 Career

Knowing how to create and manage DAGs is essential for data engineers and DevOps professionals working with workflow automation.

1

Create the DAG object

Import DAG from airflow and datetime from datetime. Then create a DAG object called my_dag with dag_id='my_first_dag' and start_date=datetime(2023, 1, 1).

Apache Airflow

# Your code here

Need a hint?

Use DAG to create the workflow object. The start_date tells Airflow when to begin scheduling.

2

Define the Python function

Define a Python function called print_hello that prints the message 'Hello from Airflow!'.

Apache Airflow

from airflow import DAG
from datetime import datetime

my_dag = DAG(dag_id='my_first_dag', start_date=datetime(2023, 1, 1))

# Your code here

Need a hint?

Define a simple function that prints a message. This function will be run by the task.

3

Create the PythonOperator task

Import PythonOperator from airflow.operators.python. Then create a task called hello_task using PythonOperator with task_id='hello_task', python_callable=print_hello, and assign it to the DAG my_dag.

Apache Airflow

from airflow import DAG
from datetime import datetime
from airflow.operators.python import PythonOperator

def print_hello():
    print('Hello from Airflow!')

my_dag = DAG(dag_id='my_first_dag', start_date=datetime(2023, 1, 1))

# Your code here

Need a hint?

Use PythonOperator to run the function as a task in the DAG.

4

Print the DAG object

Write a print statement to display the my_dag object.

Apache Airflow

from airflow import DAG
from datetime import datetime
from airflow.operators.python import PythonOperator

def print_hello():
    print('Hello from Airflow!')

my_dag = DAG(dag_id='my_first_dag', start_date=datetime(2023, 1, 1))

hello_task = PythonOperator(
    task_id='hello_task',
    python_callable=print_hello,
    dag=my_dag
)

# Your code here

Need a hint?

Use print(my_dag) to show the DAG object details.