feat(powerdns): add LUA record support

[minimalmattt]

What does it do ?

This PR adds support for the LUA record type (Exclusive to PowerDNS)

Motivation

PowerDNS supports a LUA record type (https://doc.powerdns.com/authoritative/lua-records/index.html)

It's akin to a TXT record in the fact that by itself it only stores a lua snippet in the form of text, but it is parsed differently by PowerDNS, actually executing the provided script and using the return value as the answer.

More

This feature is gated behind the "managed-record-types" argument so it's not enabled by default.

I tested this on k8s 1.32, external-dns v0.20 and powerDNS 4.8.3

• Yes, this PR title follows Conventional Commits
• Yes, I added unit tests
• Yes, I updated end user documentation accordingly

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign ivankatliarchuk for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Welcome @minimalmattt!

It looks like this is your first PR to kubernetes-sigs/external-dns 🎉. Please refer to our pull request process documentation to help your PR have a smooth ride to approval.

You will be prompted by a bot to use commands during the review process. Do not be afraid to follow the prompts! It is okay to experiment. Here is the bot commands documentation.

You can also check if kubernetes-sigs/external-dns has its own contribution guidelines.

You may want to refer to our testing guide if you run into trouble with your tests not passing.

If you are having difficulty getting your pull request seen, please follow the recommended escalation practices. Also, for tips and tricks in the contribution process you may want to read the Kubernetes contributor cheat sheet. We want to make sure your contribution gets all the attention it needs!

Thank you, and welcome to Kubernetes. 😃

[k8s-ci-robot]

Hi @minimalmattt. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work.

Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[vflaux]

I'm not sure we want to add non‑standard record types into the core code.
Could this be added as a TXT record using a providerSpecificProperty instead? Or we add an "exotic" type that could be anything and it's up to the provider to deal with it?

Cloudflare proxied records and AWS alias records are implemented through provider‑specific properties as well, but those remain standard A/AAAA/CNAME record types, unlike the LUA type from PowerDNS.

I’d like to get the maintainers’ opinion on this.

[k8s-ci-robot]

PR needs rebase.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[mloiseleur]

I strongly agree with your comment, @vflaux. This provider specific feature should not go into core code.

[minimalmattt]

HI, thanks for the feedback.
What would be the preferred approach for this? Should this be a provider-specific annotation on a TXT record, since they are pretty similar?

[mloiseleur]

@minimalmattt We have started an effort to move providers out of tree (#4347). You can make your own for powerdns and include this with a provider-specific.