(aws-cloudfront-origins): Default Lambda Function URL Origins To Dual Stack IPv4/IPv6

[rhermes62]

Describe the feature

CloudFront recently launched support for IPv6 origins.

Lambda function URL's are by default dual stack.

This feature request tracks automatically enabling dual stack support for Lambda function URL origins.

Use Case

Right now, our Lambda function URL origins are using the (now legacy) IPv4 only configuration even though they support IPv6.

We would like to leverage IPv6 where possible.

Proposed Solution

CloudFront has added IpAddressType in the CustomOriginConfig in CloudFormation.

Given that, the update should be simply updating the rendering of the CustomOriginConfig here.

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

AWS CDK Library version (aws-cdk-lib)

n/a

AWS CDK CLI version

n/a

Environment details (OS name and version, etc.)

n/a

[pahud]

Hi @rhermes62,

Thank you for this excellent feature request! You're absolutely right that we should default Lambda Function URL origins to dual stack IPv4/IPv6 since Lambda Function URLs support dual stack by default.

This is a straightforward enhancement that involves updating the FunctionUrlOrigin class's renderCustomOriginConfig() method to include the ipAddressType: 'dualstack' property in the returned CustomOriginConfig.

The implementation would need to:

1. Update both FunctionUrlOrigin and FunctionUrlOriginWithOAC classes
2. Add the ipAddressType: 'dualstack' property to the CustomOriginConfig
3. Ensure this change is backward compatible (it should be, as it only adds IPv6 support)

This aligns with AWS's direction toward IPv6 adoption and matches the default behavior of Lambda Function URLs themselves.

Would you be interested in contributing a pull request for this enhancement? The change should be relatively simple and would be a great contribution to the CDK community. If you need any guidance on the implementation approach or testing requirements, please let us know!

Related files to modify:

• packages/aws-cdk-lib/aws-cloudfront-origins/lib/function-url-origin.ts
• Add appropriate unit tests
• Update documentation if needed

Thanks again for identifying this gap and providing such a clear description of the desired behavior!

[badmintoncryer]

This modification is a breaking change and we need to add a feature flag to enable this feature.