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openshiftkubernetes-helm

Helm must override values yaml file

I have structure similar to the following example:

values.yaml

config:
  value: "unset"

values-dev.yaml

config:
  value: "development"

values-prod.yaml

config:
  value: "production"

I need to make sure that the value is set by the specific environment and, if we forget to add it to the values-*env*.yaml, the templating step should fail.

In other words, in the example above there should NEVER be "unset" in any enviornment and if we create a new values-**.yaml file with no value: "something" inside, it should fail during templating.

I couldn't find a way to do it in the documentation

Solution

  • The most straightforward path to this is to use Helm's required template function.

    In your chart's values.yaml, do not provide a value for the required-with-no-default setting. It may be helpful to include the containing value explicitly as a YAML mapping.

    # values.yaml
config: {}
  # value: not mentioned here

    At the point where you go to use the value, include required in a pipeline. That will fail if the value isn't present (more specifically if it's nil or another "falsey" value).

    # templates/deployment.yaml
env
- name: ENVIRONMENT
  value: {{ .Values.config.value | required "config.value setting is required" }}

    (You need more complex logic if it's possible the config wrapper doesn't exist either. You need different logic if "falsey" values like zero or empty-string are legitimate values, probably containing the Sprig hasKey function with Helm fail and conditionals as shown in @RuiJarimba's answer.)