In this lesson, you’ll learn what tasks and operators are in Apache Airflow, how they work together, and how to use them to build workflows.

What is a Task?

  • A task is the smallest unit of work in Airflow.

  • Each task represents one step in a workflow (DAG).

  • It has upstream and downstream dependencies set between them in order to express the order they should run in.

  • There are three basic kinds of Task:

What is an Operator?

  • An operator is a template that tells Airflow what kind of task to run.

  • When you use an operator in a DAG, it becomes a task instance.

Tip

Think of it like this:
Operator = Blueprint (what the task does).
Task = Real execution of that operator inside the DAG.

Types of Operators

Airflow provides many built-in operators, such as:

  • PythonOperator – Runs a Python function.

  • BashOperator  – Executes a Bash command/script.

  • EmailOperator  – Sends an email.

  • SqlOperator  – Runs SQL queries against a database.

  • HttpOperator  – Makes API requests.

  • DummyOperator – Placeholder for workflow structure.

Tip

You can also create Custom Operators when built-ins don’t fit your needs.​

Tasks and Operators in Action

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

# Define a function for the Python task
def greet():
    print("Hello, Airflow learner!")

# Define the DAG
with DAG(
    dag_id="example_dag",
    start_date=datetime(2025, 1, 1),
    schedule_interval="@daily",
    catchup=False
) as dag:

    # Create a task using PythonOperator
    task1 = PythonOperator(
        task_id="greet_task",
        python_callable=greet
    )

Here:

  • PythonOperator = Operator (the blueprint).

  • task1 = Task instance created from that operator.

Task Dependencies

  • Tasks can be connected using >> or << operators.

task1 >> task2

Lesson Summary​

  • Tasks = Units of work in a DAG.

  • Operators = Blueprints that define what the task does.

  • Airflow provides many operators (Python, Bash, SQL, API, Email).

  • Tasks created from operators can be linked with dependencies to build workflows.

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