Conditionals, Loops and Scope

Control structures and the dot

if / else if / else include blocks conditionally; empty strings, zero, false, nil and empty lists or maps count as false. with changes the scope: inside {{ with .Values.ingress }}, the dot . refers to .Values.ingress, and the block is skipped if the value is empty. range loops over lists or maps, again changing . to the current item; {{ range $key, $value := .Values.env }} gives you named variables. Because with and range change the dot, you can no longer write .Release.Name inside them; use $, which always points to the root context: {{ $.Release.Name }}. To embed a whole structure from values, such as resources or nodeSelector, use {{- toYaml .Values.x | nindent N }}, where N is the indentation the YAML needs at that position.

Ingress rules from a list of hosts

Inside range, $ reaches the release name and service port.

{{- if .Values.ingress.enabled }}
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ include "shop-api.fullname" . }}
  {{- with .Values.ingress.annotations }}
  annotations:
    {{- toYaml . | nindent 4 }}
  {{- end }}
spec:
  ingressClassName: {{ .Values.ingress.className }}
  rules:
    {{- range .Values.ingress.hosts }}
    - host: {{ .host | quote }}
      http:
        paths:
          - path: {{ .path | default "/" }}
            pathType: Prefix
            backend:
              service:
                name: {{ include "shop-api.fullname" $ }}
                port:
                  number: {{ $.Values.service.port }}
    {{- end }}
{{- end }}

Changing rooms in a house

with and range walk you into a room, so "the table" now means the table in that room. $ is the front door address: wherever you are, it still leads to the whole house.

Quick check: Inside a `range` block, how do you read the release name?

• .Release.Name
• $.Release.Name
• range.Release.Name
• It is not possible