Idempotent task design in Apache Airflow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a task that runs only if it hasn't run before.

Apache Airflow

def task_function(**kwargs):
    ti = kwargs['ti']
    if ti.xcom_pull(task_ids='task_id') is [1]:
        print('Running task')

Drag options to blanks, or click blank then click option'

ANone

BFalse

CTrue

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using False or 0 instead of None causes wrong checks.

The task checks if the previous run result is None, meaning it hasn't run yet.

2fill in blank

medium

Complete the code to push a result to XCom after task completion.

Apache Airflow

def task_function(**kwargs):
    ti = kwargs['ti']
    result = 'done'
    ti.xcom_push(key='status', value=[1])

Drag options to blanks, or click blank then click option'

A'result'

Bresult

C'done'

D'status'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string literal instead of the variable causes wrong data to be pushed.

The variable result holds the value to push, so it should be passed directly.

3fill in blank

hard

Fix the error in the task decorator to ensure idempotency with retries.

Apache Airflow

@task(retries=[1])
def my_task():
    pass

Drag options to blanks, or click blank then click option'

A3

B-1

CNone

D'3'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of an integer causes type errors.

The retries parameter must be an integer, not a string, to work correctly.

4fill in blank

hard

Fill both blanks to create an idempotent task that skips if output exists.

Apache Airflow

def task_function(**kwargs):
    ti = kwargs['ti']
    output = ti.xcom_pull(task_ids=[1], key=[2])
    if output is not None:
        print('Skipping task')

Drag options to blanks, or click blank then click option'

A'previous_task'

B'result'

C'current_task'

D'status'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong task IDs or keys causes the check to fail.

The task pulls the 'result' key from the 'previous_task' to check if it ran before.

5fill in blank

hard

Fill all three blanks to define an idempotent task that updates a database only once.

Apache Airflow

def update_db_task(**kwargs):
    ti = kwargs['ti']
    already_done = ti.xcom_pull(task_ids=[1], key=[2])
    if not already_done:
        # perform update
        ti.xcom_push(key=[3], value=True)

Drag options to blanks, or click blank then click option'

A'check_update'

B'update_status'

C'done'

D'update_db_task'

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up keys or task IDs breaks the idempotency check.

The task checks 'done' key from 'check_update' task and pushes 'update_status' after updating.