I'm using a sub-chart from a repository that provides a template for an ingress. Unfortunately, that template does not provide a way to specify an optional attribute I'd like to include in the generated output.
Is there a way to use the sub-chart but also supply a templated value for the attribute I want to provide?
Basically the chart you are using as a subchart is an upstream dependency for you. If it doesn't provide the option then you can add that option to it (or ask the maintainer to add it) and wait for that change to be published so that you can consume it. But that means having that influence and being able to wait. Otherwise you publish your own version i.e. you fork it. Or you take the source code of the chart and include it in your charts directory and make the change you need there - this is commonly called 'vendoring'. For more see Customize helm chart from stable repository
I expect this to change in helm3 though - https://github.com/helm/community/blob/master/helm-v3/001-charts.md
