I'd say all of these problems have answers in CUE.
> I want to be able to write a "generic environment" module for each application and then parameterize it accordingly for each environment.
This is pretty solidly in the target use case range, i'd say - managing variations of the same "object type" over some dimension is a lot of what's targeted by the way that CUE treats directory hierarchies when loading files: https://cuelang.org/docs/concepts/packages/#instances
The main thing you have to consider in designing a layout is that you have to take a compositional approach to how you define individual config instances. That is, you can't start from prod's config, then override a value or two for staging.
If i were to do it - i have not, this is not how i currently use CUE - my first approach would probably be by defining defaults at the "policy" level (per the above link), which effectively allows you to get exactly one "override"-ish behavior.
Lots of possible approaches to this, though.
> but you can't quite emulate functions as far as I can tell
Function-like capability is present, just in a form that's less familiar. I think of them as "function structs." This post has a bunch of examples https://github.com/cuelang/cue/issues/139#issuecomment-55677.... It seems there's a plan to add a more comfortable notation (https://github.com/cuelang/cue/issues/943), but it's fundamentally possible now.
> I want to be able to write a "generic environment" module for each application and then parameterize it accordingly for each environment.
This is pretty solidly in the target use case range, i'd say - managing variations of the same "object type" over some dimension is a lot of what's targeted by the way that CUE treats directory hierarchies when loading files: https://cuelang.org/docs/concepts/packages/#instances
The main thing you have to consider in designing a layout is that you have to take a compositional approach to how you define individual config instances. That is, you can't start from prod's config, then override a value or two for staging.
If i were to do it - i have not, this is not how i currently use CUE - my first approach would probably be by defining defaults at the "policy" level (per the above link), which effectively allows you to get exactly one "override"-ish behavior.
Lots of possible approaches to this, though.
> but you can't quite emulate functions as far as I can tell
Function-like capability is present, just in a form that's less familiar. I think of them as "function structs." This post has a bunch of examples https://github.com/cuelang/cue/issues/139#issuecomment-55677.... It seems there's a plan to add a more comfortable notation (https://github.com/cuelang/cue/issues/943), but it's fundamentally possible now.