`metrics.exporter.extraEnvs` does not support Kubernetes secret references

[vladislavzamuruev-arch]

metrics.exporter.extraEnvs only supports plain string values due to how the template renders them:

{{- range $key, $val := .Values.metrics.exporter.extraEnvs }}
- name: {{ $key }}
  value: "{{ $val }}"
{{- end }}

This makes it impossible to reference Kubernetes secrets (e.g. secretKeyRef) for sensitive values like passwords, which is a common requirement when running Valkey with authentication enabled and wanting to scrape metrics via redis_exporter.

Fix: update the template in statefulset.yaml and deploy_valkey.yaml to check the value type:

{{- range $key, $val := .Values.metrics.exporter.extraEnvs }}

- name: {{ $key }}
  {{- if kindIs "string" $val }}
  value: "{{ $val }}"
  {{- else }}
  valueFrom:
    {{- toYaml $val | nindent 4 }}
  {{- end }}
{{- end }}

This is backwards compatible, plain string values continue to work, while map values are treated as valueFrom blocks.

[sgissi]

@vladislavzamuruev-arch Thanks for that. We have a backlog of changes to apply, but if you can open a PR, we will get to it soon to review.

[sgissi]

@vladislavzamuruev-arch Looking at the backlog, I see there is a number of PRs already to fix authentication and encryption for the metric exporter. Do you have any additional use case for this change?