XCom with return values in Apache Airflow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to push a value to XCom using the return statement in a PythonOperator task.

Apache Airflow

def task_function():
    return [1]

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

ANone

Bprint('Hello from XCom!')

C'Hello from XCom!'

Dxcom_push('Hello from XCom!')

Attempts:

3 left

💡 Hint

Common Mistakes

Using print instead of return

Calling xcom_push directly inside the function

Returning a value from the task function automatically pushes it to XCom.

2fill in blank

medium

Complete the code to pull the XCom value from a previous task named 'push_task'.

Apache Airflow

from airflow.operators.python import PythonOperator

def pull_task(ti):
    value = ti.xcom_pull(task_ids=[1])
    print(value)

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

A'push_task'

Bpush_task

C'pull_task'

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the variable name without quotes

Using the wrong task ID

Task IDs must be passed as strings to xcom_pull.

3fill in blank

hard

Fix the error in the code to correctly return a dictionary as an XCom value.

Apache Airflow

def task_function():
    data = [1]  # dictionary to return
    return data

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

A'key: value'

B['key', 'value']

C('key', 'value')

D{'key': 'value'}

Attempts:

3 left

💡 Hint

Common Mistakes

Returning a list or tuple instead of a dictionary

Returning a string instead of a dictionary

Returning a dictionary pushes it as an XCom value correctly.

4fill in blank

hard

Fill both blanks to create a PythonOperator that pushes a return value and another that pulls it.

Apache Airflow

push_task = PythonOperator(
    task_id='push_task',
    python_callable=[1],
    dag=dag
)
pull_task = PythonOperator(
    task_id='pull_task',
    python_callable=[2],
    dag=dag
)

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

Atask_function_push

Btask_function_pull

Ctask_function

Dpull_function

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same function for both tasks

Mixing up push and pull function names

The push task uses the function that returns a value, and the pull task uses the function that pulls it.

5fill in blank

hard

Fill all three blanks to create a DAG with two tasks where the second pulls the XCom value from the first.

Apache Airflow

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

def [1]():
    return 'Data from first task'

def [2](ti):
    data = ti.xcom_pull(task_ids=[3])
    print(f'Received: {data}')

dag = DAG('xcom_example', start_date=datetime(2024, 1, 1), schedule_interval='@daily')

push = PythonOperator(task_id='push', python_callable=[1], dag=dag)
pull = PythonOperator(task_id='pull', python_callable=[2], dag=dag)
push >> pull

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

Apush_task_function

Bpull_task_function

C'push'

D'pull'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong task_id in xcom_pull

Mismatching function names and task_ids

The first function returns data, the second pulls it using the correct task ID string.