helm-extraresources-patcher

name	helm-extraresources-patcher
description	ensure all Helm charts have 'extraResources' support by patching templates/extra-resources.yaml and values.yaml. Run when searching for root charts or when a new chart is added.

Helm ExtraResources Patcher

This skill ensures that all vendored top-level Helm charts in the repository support injecting arbitrary Kubernetes resources via the extraResources value. This is useful for adding related resources like SealedSecrets or CloudNativePG Cluster without modifying upstream chart templates.

[!IMPORTANT]

• Main Charts Only: Never patch subcharts (directories inside charts/).
• Semantic Audit: Before patching, check if the chart already supports a similar feature under a different name (e.g., extraObjects, customResources, additionalResources). If it does, do NOT add a redundant extraResources field.

1. Audit Phase

1. Locate top-level charts:

   find helm -name Chart.yaml -not -path "*/charts/*" | xargs -n 1 dirname | sort -u
   

2. Evaluate existing support: For each chart directory <chart-dir>:

   • Check <chart-dir>/values.yaml for keys like extraResources, extraObjects, extraDeploy.
   • If a key exists, search grep -r inside <chart-dir>/templates to see if that key is actually being used in any template.
   • If it is already used, the chart satisfies the requirement.

2. Patching Phase

If a chart has NO mechanism for injecting extra external resources:

A. Add template file

Create <chart-dir>/templates/extra-resources.yaml with the following content:

{{- range .Values.extraResources }}
---
{{- if typeIs "string" . }}
  {{- tpl . $ }}
{{- else }}
  {{- tpl (toYaml .) $ }}
{{- end }}
{{- end }}

Each item is rendered through tpl, so Helm template expressions (e.g. {{ .Release.Namespace }}) inside extraResources values are evaluated at render time. Both object and raw string formats are supported (see values.yaml below).

B. Update values.yaml

Append the extraResources: [] definition at the end of <chart-dir>/values.yaml:

# -- Extra resources to deploy with the chart.
# Supports both object and string (multiline) formats. Helm template expressions are evaluated.
extraResources: []
  # Object format:
  # - apiVersion: v1
  #   kind: ConfigMap
  #   metadata:
  #     name: example-configmap
  #     namespace: "{{ .Release.Namespace }}"
  #   data:
  #     example-key: example-value
  #
  # String format (multiline):
  # - |
  #   apiVersion: v1
  #   kind: ConfigMap
  #   metadata:
  #     name: example-configmap
  #     namespace: "{{ .Release.Namespace }}"

C. Update values.schema.json (Optional)

If <chart-dir>/values.schema.json exists, MUST add extraResources to the properties block:

        "extraResources": {
            "type": "array",
            "items": {
                "oneOf": [
                    { "type": "string" },
                    { "type": "object" }
                ]
            }
        }

Failure to update the schema will cause helm template to fail if additionalProperties: false is set.

3. Verification

1. Verify template rendering: Run helm template . in the patched directory to ensure it doesn't break basic rendering.

2. Test object format:

   helm template . --set "extraResources[0].apiVersion=v1,extraResources[0].kind=ConfigMap,extraResources[0].metadata.name=test"
   

3. Test string format with Helm expression:

   helm template . --set-string 'extraResources[0]=apiVersion: v1\nkind: ConfigMap\nmetadata:\n  name: test\n  namespace: "{{ .Release.Namespace }}"'
   

   Confirm that {{ .Release.Namespace }} is rendered as the actual namespace, not left as a literal string.