helm template - let users introduce their custom ENVs based on ConfigMap in supported resources

helm_template.yaml

env:
- name: POD_NAME
  valueFrom:
    fieldRef:
      apiVersion: v1
      fieldPath: metadata.name
- name: POD_NAMESPACE
  valueFrom:
    fieldRef:
      apiVersion: v1
      fieldPath: metadata.namespace
{{- if .Values.envConfigs }}
{{- range $key, $config := $.Values.envConfigs }}
- name: {{ $key }}
  valueFrom:
    configMapKeyRef:
      name: {{ $config }}
      key: {{ $key | quote }}
{{- end }}
{{- end }}

values.yaml

#
# values.yaml
#
envConfigs:
  Q3_CFG_MAP: Q3DM17
  Q3_CFG_TIMEOUT: 30

# if empty use: 
# envConfigs: {}