How to pass entire JSON string to Helm chart value?

Question

How can I pass the entire JSON string to a Helm chart value?

I have values.yml where the config value should contain entire JSON with a configuration of an application

...
config: some JSON here
...

and I need to pass this value to a secret template and then mount it as a volume to a Kubernetes pod.

{{- $env := default "integration" .Values.env}}
apiVersion: v1
kind: Secret
metadata:
  name: {{ .Release.Name }}-{{ $env }}
type: Opaque
data:
  config.json: {{ .Values.config | b64enc | quote }}

However the obvious approach of passing single quoted string like '{"redis": "localhost:6379"}' fails because Helm for some reason deletes all double quotes in the string (even if I escape them) so I end up with {redis: localhost:6379} which is not a valid JSON.

Is there any other possibility how to pass configuration to the pod all at once without loading template files with tpl function and making all needed fields accessible via values.yml separately?

Answer 1

If .Values.config contains json then you can use it in your templated Secret with {{ .Values.config | toJson | b64enc | quote }}. It may seem strange to use toJson to convert json to json but helm doesn't natively treat it as json until you tell it to. See the SO question How do I use json variables in a yaml file (Helm) for an example of doing this.

Answer 2

Here is another suggestion if you want to avoid encoding :

env:
  - name: MYCONFIG
  value: {{ .Files.Get "config.json" | toPrettyJson }}

According to the helm docs, helm uses template functions such as toPrettyJson which are supplied by the built-in Go text/template package and the Sprig template function library.