Helm use template function inside llops - kubernetes-helm

Question

I am trying to use the {{ template }} function on my helm chart, but inside a loop the value does error.
First here is my _helpers.tpl:
{{- define "traefik.deployNamespace" -}}
{{ default "kube-system" .Values.deployNamespace }}
{{- end -}}
I can use that variable with {{ template "treafik.deployNamespace }} on all the templates, expect when inside a loop:
# Iterates on allowed namespaces and creates the roles
{{- if .Values.allowedNamespaces }}
{{- range .Values.allowedNamespaces }}
# Rules for namespace: {{ . }}
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: {{ . }}-traefik-ingress-r
namespace: {{ . }}
rules:
- apiGroups:
- ""
resources:
- services
- endpoints
- secrets
verbs:
- get
- list
- watch
- apiGroups:
- extensions
resources:
- ingresses
verbs:
- get
- list
- watch
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: {{ . }}-traefik-ingress-rb
namespace: {{ . }}
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: {{ . }}-traefik-ingress-r
subjects:
- kind: ServiceAccount
name: traefik-ingress-sa
namespace: {{ template "traefik.deployNamespace" . }}
{{- end }}
{{- end }}
I am probably doing the $ctx wrong, but I don't know what I should use in there.
> % helm template .
Error: template: traefik/templates/_helpers.tpl:62:36: executing "traefik.deployNamespace" at <.Values.deployNamespace>: can't evaluate field Values in type strin

Answer 1

At the bottom of the file you have a couple of uses of the . current-context variable. Inside the context of a {{ range }}...{{ end }} loop, . gets set to the item from the list you're iterating over.
# `.` in all three of these is the same thing (a string)
name: {{ . }}-traefik-ingress-rb
namespace: {{ . }}
namespace: {{ template "traefik.deployNamespace" . }}
Templates generally expect to get the top-level Helm environment object as their parameter (a dictionary-type object with "Charts", "Values", and so on). You need to save it away outside your loop in a variable so you can get access to it.
{{- $top := . }}
{{- range .Values.allowedNamespaces }}
...
namespace: {{ template "traefik.deployNamespace" $top }}
...
{{- end }}