feat(vector): allow templating pod annotations

[elohmeier]

Workload templates now render podAnnotations through tpl, so users can supply templated checksums (e.g. hashing external ConfigMaps) without chart changes. This is useful when no cluster access is available e.g. when using the rendered manifest pattern.

[pront]

Looks reasonable.

Can this theoretically break someone if they had literal double-brace strings in their annotations?

  podAnnotations:
    example: "This is a {{ literal string }}"  # Would now be interpreted as template

[elohmeier]

I found a way to work around this limitation using:

rollWorkloadExtraObjects: true
dataDir: /vector-data-dir
existingConfigMaps:
  - vector-external-config
extraObjects:
  - apiVersion: v1
    kind: ConfigMap
    metadata:
      name: vector-external-config
      namespace: "{{ .Release.Namespace }}"
    binaryData:
      vector.yaml: '{{ .Files.Get "files/vector.yaml" | b64enc }}'

After further analysis, this workaround does not work - helm won't cross chart file boundaries, so it cannot access files e.g. when Vector is used as a subchart/dependency.

[elohmeier]

Looks reasonable.

Can this theoretically break someone if they had literal double-brace strings in their annotations?

  podAnnotations:
    example: "This is a {{ literal string }}"  # Would now be interpreted as template

@pront Thanks for your feedback. Yes this would break in that scenario. Given the intended use cases for annotations I think this would still be a reasonable "breaking" change.