score/disruptionbudget: output comment when namespace doesn't match

[cayla]

I was troubleshooting a strange kube-score failure regarding PodDisruptionBudget.

kube-score was complaining that a deployment didn't have a PDB even though it very much did.

Going back to the code I realized the test was exiting early due to the namespace check:

https://github.com/zegl/kube-score/blob/0b3f154ca3f06a13323431a7d2199a74a1869fbc/score/disruptionbudget/disruptionbudget.go#L23-L25

Obviously, this was a bad manifest on my end (explicit is better than implicit and the tests passed as soon as I added namespace: {{ .Release.Namespace }} to my helm charts), but perhaps with a bit more output we could help other folks connect the dots faster.

RELNOTE: score/disruptionbudget: output comment when namespace doesn't match

[zegl]

Hey, thanks for the PR. This comment would fire for every PDB until a matching one is found, and can fire even if a PDB ends up getting found by later iterations of the loop.

Could you move this comment down to just before return false, nil, and only set this comment if any PDB has been ignored to mismatched namespaces?

Something like:

func hasMatching(budgets []ks.PodDisruptionBudget, namespace string, labels map[string]string) (bool, error) {
    var hasNamespaceMismatch bool
    for _, budget := range budgets {
        if budget.Namespace() != namespace {
            hasNamespaceMismatch = true
            continue
        }

        selector, err := metav1.LabelSelectorAsSelector(budget.PodDisruptionBudgetSelector())
        if err != nil {
            return false, fmt.Errorf("failed to create selector: %w", err)
        }
        if selector.Matches(internal.MapLabels(labels)) {
            return true, nil
        }
    }

    if hasNamespaceMismatch {
        score.AddComment("", "PodDisruptionBudget not found", "Cannot associate the PodDisruptionBudget to the resource because they are not explicitly in the same namespace")
    }

    return false, nil
}

[cayla]

Thank you for your feedback. If you can't tell, I am not a proper dev, let alone a go dev. But i am trying to give back more lately even if it means I goof up now and then.

I took your advice on getting the output outside the loop. I also converted the message to a error like the selector. Yesterday I failed to notice my linter complaining about score being undefined. I was going to crack open some go documentation to learn how to do that right when I thought, this actually is more like an error anyway -- like the selector.

Anyway, hope this is helpful. If not, no worries. I appreciate your tool. When I was getting started in k8s, it was invaluable to avoiding potholes.

PS - I built locally and ran the tests wo/ failure

[zegl]

Thanks, this looks great!