feat: add a passthrough map to configuration

[jeacott1]

It would be helpful for downstream configuration if kubestack users could include arbitrary per environment configuration in the standard structure that was passed through to the output.

ie: given the usual

configuration = {
    apps = {
       #add a map where users can just pass through whatever they like.
       custom = {
          ENV_mycustomconfig = ""
          DISK_size = 500
       }
    }

This could be exported as its own map(map(string/any/?)) and subsequently used in arbitrary foreach blocks instead of having to duplicate the configuration/apps/ops/whatever to add custom bits and pieces.
I suggest a separate export here just because 3 levels of map usually gets awkward in tf.

thoughts?

[pst]

I'm not quite sure what this is supposed to do or be used for. The configuration var is of type map any. Why isn't what you are trying to do working?

[jeacott1]

@pst true, but the setunion won't copy nested maps.

[pst]

I can't follow. I suggest you take a look at the code. https://github.com/kbst/terraform-kubestack/blob/master/common/configuration/outputs.tf

[jeacott1]

@pst you are right, it will include the map I wanted, but any overrides in other environments will completely replace instead of amending the map. I guess thinking about it, what I am really asking for here is a special cased variable that would not be a blanket replace in ops/dev etc, where the default map values are preserved unless overridden. It would just be a nice to have option I think. It would help if tf had better support for deep merge but for now at least it doesn't.

[pst]

Are you planning to send a PR to support merging of nested maps?