Task retry and error handling in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to retry a task after failure using Celery's retry method.

Django

from celery import shared_task

@shared_task(bind=True)
def fetch_data(self):
    try:
        # code that might fail
        pass
    except Exception as e:
        raise self.[1](exc=e, countdown=5)

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

Aabort

Bfail

Cretry

Dstop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'fail' or 'abort' instead of 'retry' causes the task to stop immediately.

Not using 'self.' before the method causes an error.

The retry method is used inside a Celery task to retry the task after an exception.

2fill in blank

medium

Complete the code to catch a specific exception and retry the task.

Django

from celery import shared_task

@shared_task(bind=True)
def process_file(self, filename):
    try:
        # process the file
        pass
    except [1] as e:
        raise self.retry(exc=e, countdown=10)

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

ATypeError

BValueError

CKeyError

DFileNotFoundError

Attempts:

3 left

💡 Hint

Common Mistakes

Catching the wrong exception causes the retry not to trigger.

Using a generic exception hides specific errors.

We catch FileNotFoundError to retry when the file is missing.

3fill in blank

hard

Fix the error in the task to properly handle retries with max retries limit.

Django

from celery import shared_task

@shared_task(bind=True, max_retries=3)
def send_email(self, user_id):
    try:
        # send email code
        pass
    except Exception as e:
        raise self.retry(exc=e, countdown=[1])

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

A5

B10

C60

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using zero causes immediate retry and possible overload.

Using too large values delays retries unnecessarily.

The countdown sets the delay before retry. 5 seconds is a reasonable retry delay.

4fill in blank

hard

Fill both blanks to catch a timeout error and retry after 15 seconds.

Django

from celery import shared_task
import requests

@shared_task(bind=True)
def fetch_url(self, url):
    try:
        response = requests.get(url, timeout=5)
    except [1] as e:
        raise self.retry(exc=e, countdown=[2])

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

Arequests.exceptions.Timeout

Brequests.exceptions.ConnectionError

C10

D15

Attempts:

3 left

💡 Hint

Common Mistakes

Catching the wrong exception causes no retry.

Using wrong countdown delays retries incorrectly.

We catch requests.exceptions.Timeout and retry after 15 seconds.

5fill in blank

hard

Fill all three blanks to create a task that retries on ValueError with max 4 retries and 20 seconds delay.

Django

from celery import shared_task

@shared_task(bind=True, max_retries=[1])
def calculate(self, data):
    try:
        # calculation code
        pass
    except [2] as e:
        raise self.retry(exc=e, countdown=[3])

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

A4

BValueError

C20

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong exception type prevents retry.

Setting max_retries too low or countdown too short.

The task retries up to 4 times on ValueError with 20 seconds delay between retries.