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Troubleshooting `TooManyCookieNamesInWhiteListException` in AWS CloudFront

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By Exception Decoded 3 min read

Introduction:

Are you encountering the TooManyCookieNamesInWhiteListException error when configuring your AWS CloudFront distribution? Don’t worry, you’re not alone! In this comprehensive guide, we’ll delve into the causes and solutions for this error. We’ll explore the underlying concepts, explain how to troubleshoot the issue, and provide code examples to help you quickly resolve the problem. So let’s get started!

What is TooManyCookieNamesInWhiteListException?

TooManyCookieNamesInWhiteListException is an error that occurs when the number of cookie names provided in the CloudFront cookie whitelist exceeds the allowable limit. AWS CloudFront, a content delivery network (CDN) service, uses this whitelist to control which cookies are forwarded to your origin server during request processing.

Causes of TooManyCookieNamesInWhiteListException

There are two major causes for encountering the TooManyCookieNamesInWhiteListException error:

  1. Exceeding the maximum number of cookie names: AWS CloudFront restricts the number of cookie names that can be included in the whitelist. By default, this limit is set to 10. If your distribution has more than ten cookie names in the whitelist, you’ll encounter this exception.

  2. Invalid cookie name format: AWS CloudFront imposes specific rules for cookie names that can be included in the whitelist. If any of the cookie names violate these rules, the exception will be triggered.

Troubleshooting Steps

To resolve the TooManyCookieNamesInWhiteListException, follow these steps:

Step 1: Verify the Whitelist Configuration

Start by examining your distribution’s configuration and the cookie whitelist settings. You can use the AWS Management Console, AWS CLI, or CloudFormation to access and modify your CloudFront resources.

  1. Open the CloudFront console on the AWS Management Console.

  2. Select the desired distribution and go to the Behaviors tab.

  3. Locate the behavior you’re troubleshooting, click on the Edit button, and scroll down to the Cache key and origin requests settings section.

  4. Ensure the Forward Cookies option is enabled.

  5. Review the list of cookie names included in the whitelist. If you have more than ten cookie names, you’ll need to reduce the count.

  6. Verify that the cookie names comply with the required format guidelines.

If you’ve exceeded the maximum limit, you’ll need to prune your cookie names list. Determine which cookies are essential for your application’s functionality and remove any unnecessary ones. Remember, AWS CloudFront handles cookies on the edge locations, so limiting the number of cookies improves performance and reduces complexity.

When a cookie name violates the required format, you’ll encounter the TooManyCookieNamesInWhiteListException. Check each cookie name for any disallowed characters or length limitations. Use the following guidelines when renaming cookie names:

  • The cookie name must be at least one character long.

  • It can’t start with $ and can’t contain any of the following characters: =,; \t\r\n\f\v.

  • The cookie name must be ASCII only.

Step 4: Update the Distribution

Once you’ve adjusted and verified the whitelist configuration, it’s time to update your AWS CloudFront distribution to apply the changes.

  1. Navigate to the General tab of your CloudFront distribution configuration.

  2. Click on the Edit button.

  3. Scroll down and select Yes for the Save option to apply the changes.

  4. Review the changes and click the Confirm button.

  5. Wait for the distribution update process to complete.

Example Code

Let’s look at an example of modifying the distribution settings using AWS CLI:

  1. To retrieve the distribution configuration, execute the following command:
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aws cloudfront get-distribution-config --id <distribution-id>

  1. Save the output locally for backup purposes.

  2. Update the distribution’s cookie whitelist configuration as required. Here’s an example command:

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aws cloudfront update-distribution --id <distribution-id> --distribution-config file://distribution-config.json

Ensure that the distribution-config.json file contains the updated configuration.

  1. The distribution update status can be checked by running the following command:
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aws cloudfront get-distribution --id <distribution-id> --query 'Distribution.Status'

Conclusion

In this guide, we explored the TooManyCookieNamesInWhiteListException error in AWS CloudFront. We discussed its causes, troubleshooting steps, and provided example code to help you resolve the issue. Remember to review your distribution’s whitelist configuration, remove unnecessary cookie names, and ensure cookie names comply with the required format. With these steps, you can overcome this issue and optimize your CloudFront distribution’s performance.

If you’d like to learn more about AWS CloudFront and its capabilities, refer to the official AWS documentation here.

Happy troubleshooting!

AWS, AWS CloudFront
aws cloudfront com.amazonaws.services.cloudfront.model
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