I have the following template in _helpers.tpl:

{{/* Get the system admin username from secret
*/}}
{{- define "get-system-admin-username-value" -}}
  {{- $secretObj := (lookup "v1" "Secret" .Release.Namespace "my-secret") }}
  {{- if and $secretObj (index $secretObj.data "username") }}
    {{- $secretValue := (index $secretObj.data "username") | b64dec }}
    {{- $secretValue }}
  {{- else }}
    {{- "undefined" }}
  {{- end }}
{{- end }}

I call this function the following way:

apiVersion: v1
kind: Pod

metadata:
  name: "{{ .Chart.Name }}"
  labels:
    {{- include "labels" . | nindent 4 }}
  namespace: {{ default "undefined" $.Values.env.NAMESPACE }}
spec:
  containers:
   - name: "{{ $.Chart.Name }}--xxx"
     env:
        - name: SYSTEM_ADMIN_USERNAME
          value: {{ include "get-system-admin-username-value" . | default "undefined" }}
        - name: SYSTEM_ADMIN_PASSWORD
          value: {{ include "get-system-admin-password-value" . | default "undefined" }}

When running, I get the following error:

error calling include: template: _helpers.tpl: executing "get-system-admin-username-value" at <.Release.Namespace>: can't evaluate field Release in type string

What seems to be the issue here?

I’ve already tried passing the namespace from the helm chart as a string, I get the same error, also excluding the if statement, and every possible combination of root context ‘$’.