Support Kustomize labels property in HelmRelease postRenderers

[merusso]

I'd like to use Kustomize labels to set k8s labels across all objects in a Helm release.

According to the docs, HelmRelease.spec.postRenderers.kustomize doesn't expose this labels property.

For example, I want to set the labels foo: foo1 and bar: bar1 on all Helm objects. If I could use the Kustomize labels property, I could do the following:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
spec:
  postRenderers:
  - kustomize:
      labels:
        - pairs:
            foo: foo1
            bar: bar1
      includeTemplates: true

Otherwise, I would need to perform some kind of patch, which is harder and has some tricky edge cases. Example:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
spec:
  postRenderers:
  - kustomize:
      patchesJson6902:
      # Patch all objects
      # Note: This fails if a Helm template is missing metadata.labels property
      - patch:
        - op: add
          path: /metadata/labels/foo
          value: foo1
        - op: add
          path: /metadata/labels/bar
          value: bar1
        target:
          name: .*
      # Patch Deployment's Pod template
      - patch:
        - op: add
          path: /spec/template/metadata/labels/foo
          value: foo1
        - op: add
          path: /spec/template/metadata/labels/bar
          value: bar1
        target:
          kind: Deployment
          name: .*

[merusso]

I didn't receive any negative feedback on this (only upvotes), so I created issue fluxcd/helm-controller#794