How do I use json variables in a yaml file (Helm)

Question

I have a HELM values file which looks like so:

service:
  environment: dev
  spring_application_json: >-
    {
      "spring" : {
        "boot" : {
          "admin" : {
            "client" : {
              "enabled" : "false",
              "url" : "http://website1",
              "instance" : {
                "service-base-url" : "http://website2",
                "management-base-url" : "http://website3"
              }
            }
          }
        }
      }
    }

And a corresponding template file which grabs this value and inserts it as an environment variable to a container.

spec:
  replicas: {{ .Values.replicaCount }}
  template:
    spec:
      imagePullSecrets:
        - name: {{ .Values.image.pullSecret }}
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          env:
            - name: ENVIRONMENT
              value: "{{ .Values.service.environment }}"
            - name: SPRING_APPLICATION_JSON
              value: "{{ .Values.service.spring_application_json }}"

However when I run the helm install I get the following error:

Error: YAML parse error on deployment.yaml: error converting YAML to JSON: yaml: line 40: did not find expected key

Which points to the line:

value: "{{ .Values.service.spring_application_json }}"

I believe its a problem with the way I'm trying to parse in a json string as a multiline environment variable? The ENVIRONMENT 'dev' variable works perfectly and this same YAML also works perfectly with docker-compose.

Did you consider publishing the SPRING_APPLICATION_JSON string value within a Kubernetes configmap? — chrisinmtown, Apr 25 '19 at 18:35

score 36 · Accepted Answer · answered Oct 22 '18 at 13:58

There's an example a bit like this in the docs for spring cloud dataflow but the format in their documentation has the quotes escaped.

I was able to recreate the error and get past it by changing the values file entry to:

service:
  spring_application_json:
    {
      "spring" : {
        "boot" : {
          "admin" : {
            "client" : {
              "enabled" : "false",
              "url" : "http://website1",
              "instance" : {
                "service-base-url" : "http://website2",
                "management-base-url" : "http://website3"
              }
            }
          }
        }
      }
    }

And the deployment entry to:

    - name: SPRING_APPLICATION_JSON
      value: {{ .Values.service.spring_application_json | toJson | quote }}

Notice no quotes around this part as that is handled anyway.

That's awesome Ryan - thanks for taking the time to help. – Garreth Oct 22 '18 at 15:12 — Garreth, Oct 22 '18 at 15:12

How do I use json variables in a yaml file (Helm)

1 Answers1

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