feat: Add renewBeforePercentage alternative to renewBefore

[cbroglie]

Since the actual duration is unknown until a cert has been issued,
providing an absolute duration for renewBefore can result in accidental
renewal loops. The new renewBeforePercentage field computes the
effective renewBefore using the actual duration, allowing users to
better express intent while maintaining backwards compatibility.

Fixes #4423, resolves #5821

Pull Request Motivation

#4423 (comment)

Kind

/kind feature

Release Note

Add renewBeforePercentage alternative to renewBefore

[cert-manager-prow]

Hi @cbroglie. Thanks for your PR.

I'm waiting for a cert-manager 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.

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/test-infra repository.

[cbroglie]

I can do a pass to update the relevant docs as well if things look reasonable functionality wise.

I considered introducing a DurationOrPercent type, similar to IntOrString. But with all of the logic localized to RenewalTime there was only a single place to update, and unlike IntOrString, both duration and percentages are serialized as strings.

[inteon]

Upstream union API type: https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apimachinery/pkg/util/intstr/intstr.go

[inteon]

/ok-to-test

[inteon]

@cbroglie the tests are failing, could you take a look?

[cbroglie]

@cbroglie the tests are failing, could you take a look?

Yep, will do. I was only running make test locally; looks like I need to make some fixes to the integration/e2e tests.

[inteon]

Thank you @cbroglie for this well-written feature!
/approve
/lgtm
/hold for a bit, in case another reviewer wants to add additional comments.

[cert-manager-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: inteon

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

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [inteon]

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

[SgtCoDFish]

Hey, really appreciate you raising this - it's a great addition and it makes a tonne of sense.

We discussed this today (2024-05-14) and we love the idea but we're scared of the breaking change to our Go API. I've added a comment with a suggested change which wouldn't be breaking; what do you think?

[cert-manager-prow]

New changes are detected. LGTM label has been removed.