Purging CDN cache in Azure - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a CDN endpoint purge request using Azure SDK.

Azure

cdn_client.purge_content(resource_group_name, profile_name, endpoint_name, content_paths=[1])

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

A['*']

B['/*']

C/*

D'/*'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string instead of a list causes a type error.

Using an incorrect wildcard pattern like '*' without slash.

The purge_content method expects a list of content paths to purge. Using ['/*'] purges all cached content.

2fill in blank

medium

Complete the code to authenticate with Azure before purging CDN cache.

Azure

from azure.identity import [1]
credential = [1]()

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

AInteractiveBrowserCredential

BClientSecretCredential

CAzureCliCredential

DDefaultAzureCredential

Attempts:

3 left

💡 Hint

Common Mistakes

Using ClientSecretCredential without providing client ID and secret.

Using AzureCliCredential without Azure CLI installed.

DefaultAzureCredential automatically picks the best available authentication method for Azure SDK clients.

3fill in blank

hard

Fix the error in the purge request code by completing the missing parameter.

Azure

cdn_client.purge_content(resource_group_name, profile_name, [1], content_paths=['/images/*'])

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

Aendpoint_name

Bcdn_profile

Cresource_name

Dcache_endpoint

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the profile name twice.

Using incorrect parameter names causing runtime errors.

The third parameter must be the endpoint name to specify which CDN endpoint to purge.

4fill in blank

hard

Fill both blanks to define the Azure CDN purge function with correct parameters.

Azure

def purge_cdn_cache([1], [2]):
    cdn_client.purge_content(resource_group, profile, endpoint, content_paths=['/*'])

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

Aresource_group

Bprofile

Cendpoint

Dcontent_paths

Attempts:

3 left

💡 Hint

Common Mistakes

Using content_paths as a parameter when it is fixed inside the function.

Mixing up profile and endpoint parameters.

The function needs resource group and endpoint as parameters to identify the CDN endpoint to purge.

5fill in blank

hard

Fill all three blanks to build a dictionary for CDN purge request with dynamic keys.

Azure

purge_request = {
    [1]: [2],
    'contentPaths': [3]
}

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

A'endpointName'

Bendpoint_name

C['/*']

D'resourceGroup'

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names as keys without quotes.

Passing a string instead of a list for contentPaths.

The dictionary keys and values must match the expected purge request format: 'endpointName' key with endpoint_name variable, and 'contentPaths' with list of paths.

Practice

1. What is the main purpose of purging a CDN cache in Azure?

easy

A. To increase the storage capacity of the CDN

B. To remove outdated content so users get the latest version

C. To add new content to the CDN cache

D. To monitor traffic statistics on the CDN

Solution

1. Step 1: Understand CDN cache role

   CDN caches store copies of content to serve users faster.

2. Step 2: Purpose of purging cache

   Purging removes old cached content so fresh content is served.

3. Final Answer:

   To remove outdated content so users get the latest version -> Option B

4. Quick Check:

   Purging = Remove outdated content [OK]

Hint: Purging means clearing old cache to refresh content [OK]

Common Mistakes:

• Thinking purging adds content instead of removing
• Confusing purging with monitoring or scaling
• Believing purging increases storage capacity

2. Which Azure CLI command correctly purges the CDN cache for a specific content path?

easy

A. az cdn endpoint purge --resource-group MyGroup --profile-name MyProfile --name MyEndpoint --content-paths '/images/*'

B. az cdn endpoint create --resource-group MyGroup --profile-name MyProfile --name MyEndpoint --content-paths '/images/*'

C. az cdn endpoint start --resource-group MyGroup --profile-name MyProfile --name MyEndpoint --content-paths '/images/*'

D. az cdn profile purge --resource-group MyGroup --name MyProfile --content-paths '/images/*'

Solution

1. Step 1: Identify correct command for purging

   The command to purge cache is az cdn endpoint purge.

2. Step 2: Check parameters

   It requires resource group, profile name, endpoint name, and content paths.

3. Final Answer:

   az cdn endpoint purge --resource-group MyGroup --profile-name MyProfile --name MyEndpoint --content-paths '/images/*' -> Option A

4. Quick Check:

   Purging uses az cdn endpoint purge [OK]

Hint: Purge command uses 'endpoint purge' with content paths [OK]

Common Mistakes:

• Using 'create' or 'start' commands instead of 'purge'
• Confusing profile purge with endpoint purge
• Omitting required parameters like endpoint name

3. Given this Azure CLI command:
az cdn endpoint purge --resource-group RG1 --profile-name Profile1 --name Endpoint1 --content-paths '/css/*' '/js/app.js'
What will happen after running it?

medium

A. The command will fail due to incorrect syntax

B. Only the '/css/*' files will be purged from the CDN cache

C. Both '/css/*' and '/js/app.js' files will be purged from the CDN cache

D. Only '/js/app.js' will be purged, '/css/*' will be ignored

Solution

1. Step 1: Analyze content-paths parameter

   The command lists two paths: '/css/*' and '/js/app.js'. Both are valid and separated by space.

2. Step 2: Understand purge effect

   Both specified paths will be purged from the CDN cache after command runs.

3. Final Answer:

   Both '/css/*' and '/js/app.js' files will be purged from the CDN cache -> Option C

4. Quick Check:

   Multiple paths purge all listed [OK]

Hint: Multiple content paths purge all specified files [OK]

Common Mistakes:

• Assuming only first path is purged
• Thinking command syntax is invalid with multiple paths
• Believing wildcard and file path cannot be combined

4. You run this command to purge CDN cache:
az cdn endpoint purge --resource-group RG1 --profile-name Profile1 --name Endpoint1 --content-paths '/images/logo.png'
But the cache is not cleared. What is the most likely cause?

medium

A. The content path is incorrect or does not match cached files

B. The resource group name is misspelled

C. The Azure CLI command does not support purging images

D. The CDN endpoint is not created yet

Solution

1. Step 1: Check command correctness

   The command syntax is correct and supports purging images.

2. Step 2: Identify common purge failure reason

   If cache is not cleared, often the content path does not match cached files exactly.

3. Final Answer:

   The content path is incorrect or does not match cached files -> Option A

4. Quick Check:

   Incorrect path = purge fails [OK]

Hint: Verify content path matches cached files exactly [OK]

Common Mistakes:

• Assuming CLI cannot purge images
• Ignoring typos in resource group or endpoint names
• Thinking purge works instantly without matching paths

5. You manage a global website using Azure CDN. You want to purge cache for a frequently updated JavaScript file but minimize performance impact. Which strategy is best?

hard

A. Disable CDN caching for all files to avoid purging

B. Purge the entire CDN endpoint cache every hour

C. Purge cache only once a month to reduce load

D. Purge only the specific JavaScript file path instead of the entire CDN endpoint

Solution

1. Step 1: Understand impact of purging scope

   Purging entire endpoint cache causes high load and delays for all users.

2. Step 2: Choose targeted purging

   Purging only the specific JavaScript file updates that content with minimal performance impact.

3. Final Answer:

   Purge only the specific JavaScript file path instead of the entire CDN endpoint -> Option D

4. Quick Check:

   Targeted purge = minimal impact [OK]

Hint: Purge specific files, not whole endpoint, to save performance [OK]

Common Mistakes:

• Purging entire cache too often causing slowdowns
• Disabling caching loses CDN benefits
• Purging too rarely causing stale content