How to generate Helm charts config file with JSON data

Question

I want to generate complex JSON with HELM template

I have a template:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  config.json: |
  {
    "test": "{{ $Value }}",
    "services": {
      {{- range $k, $v := $.Values.services }}
      "{{ $k | upper }}_PATH": "{{ $k }}",
      {{- end }}
     }
  }

Helm chars generates json:

{
  "test": "test",
  "services": {
     "S1_PATH": "/t1",
     "S2_PATH": "/t2",
     "S2_PATH": "/t3",
   }
}

Problem is that JSON is not valid as it has a trailing comma. How to update the template to resolve this?

You could find a answer for your question on this other StackOverflow thread https://stackoverflow.com/questions/42662525/go-template-remove-the-last-comma-in-range-loop — Yor Jaggy, Oct 27 '22 at 14:00

score 2 · Answer 1 · answered Nov 05 '19 at 14:35

If you update the template like this, it should work.

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  config.json: |
  {
    "test": "{{ $Value }}",
    "services": {
      {{- range $k, $v := $.Values.services }}
      {{ if ne $k 0 }},{{ end }}
      "{{ $k | upper }}_PATH": "{{ $k }}"
      {{- end }}
     }
  }

For the first service (index is 0) it does not place a comma and for all others it places one in front.

score 0 · Answer 2 · answered Jul 11 '19 at 16:11

Maybe I dont undersood your question correctly, but to avoid trailing comma, you should remove it from your template. Plus I see you should use .Values.services instead of $.Values.services

template:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  config.json: |
  {
    "services": {
      {{- range $k, $v := .Values.services }}
      "{{ $k | upper }}_PATH": "{{ $k }}"
      {{- end }}
     }
  }

result:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  config.json: |
  {
    "services": {
      "S1_PATH": "s1"
      "S2_PATH": "s2"
      "S3_PATH": "s3"
     }
  }

If this i snot you expected - please add more info in your question.

It is wrong as you have to have commas after s1 and s2. If you try to parse it you will get an exception. — Mindaugas Jaraminas, Jul 12 '19 at 07:11

score 0 · Answer 3 · answered Nov 29 '22 at 12:09

0

How about straightforward:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  config.json: {{ .Values.servicePathes | toJson }}

# values.yaml
servicePathes:
 services:
  S1_PATH: "s1"
  S2_PATH: "s2"
  S3_PATH: "s3"

answered Nov 29 '22 at 12:09

igorushi

1,855
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How to generate Helm charts config file with JSON data

3 Answers3