Helm optional nested variables

Question

How do I make an optional block in the values file and then refer to it in the template?

For examples, say I have a values file that looks like the following:

# values.yaml
foo:
   bar: "something"

And then I have a helm template that looks like this:

{{ .Values.foo.bar }}

What if I want to make the foo.bar in the values file optional? An error is raised if the foo key does not exist in the values.

I've tried adding as an if conditional. However, this still fails if the foo key is missing:

{{ if .Values.foo.bar }}
{{ .Values.foo.bar }}
{{ end }}

Any thoughts are much appreciated.

Answer 1

Most charts will default the parent object to a empty map in values.yaml so it always exists.

foo: {}

Then {{ if .Values.foo.bar }} works.

If that's not possible, test both keys:

{{ if .Values.foo }}
{{ if .Values.foo.bar }}
{{ .Values.foo.bar }}
{{ end }}
{{ end }}

Using the and function doesn't work in this case due to and evaluating all parameters, even if the first is falsey.

There is also the hasKey function included from sprig if you ever need to check the existence of a falsey or empty value:

{{ if hasKey .Values.foo "bar" }}