How to render list (slice) of string as list in yaml file by Helm Chart

I have a list or (slice) of string data for example [string1, string2, string3]. I want to render it in list fashion in yaml file as

- string1
- string2
- string3

How can I do that?

I have tried

{{- range $val := $list }}
  - {{ $val }}
{{- end }}

but it renders following as multiple line of strings

- |-
   - string1
   - string2
   - string2

any idea? thank you in advance

Solution

You may use formatted string output to solve the problem.

eg.

values.yaml

arr:
  - string1
  - string2
  - string3

_helpers.tpl

{{/*
Print string from list split by ,
*/}}
{{- define "print.list" -}}
{{- range $idx, $val := $.Values.arr -}}
{{- if $idx }}
{{- print ", "  -}} 
{{- end -}}
{{- $val -}}
{{- end -}}
{{- end -}}

The template you want to render, for example comfigmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ include "test.fullname" . }}
data:
  test: [{{- include "print.list" .}}]

output

piVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  test: [string1, string2, string3]

---↓ 2022-01-05 update ↓---

values.yaml

arr:
  - string1
  - string2
  - string3

The template you want to render, for example comfigmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ include "test.fullname" . }}
data:
  test: |
    {{- toYaml $.Values.arr | nindent 4 }}

output

piVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  test: |
    - string1
    - string2
    - string3

no pipe

helm --dry-run --debug template test .

The template you want to render, for example comfigmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ include "test.fullname" . }}
data:
  test: 
    {{- toYaml $.Values.arr | nindent 4 }}

output

piVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  test: 
    - string1
    - string2
    - string3

range

{{- range $i, $v := $.Values.arr }}
- {{ $v }}
{{- end }}

output

- string1
- string2
- string3