Now, let me reverse the question—what would make you keep the tab open?"
Give me some well supported libraries in common general purpose languages to do this, codegen is pretty good these days and supporting 3 or 4 languages shouldn’t be an insurmountable achievement.
If all you’re doing is defining configurations (example is Kubernetes manifests helm charts etc) then great. But that isn’t what this is.
To your original question, I would actually advocate using the general purpose programming language for most use cases. Learning a new DSL, like you mentioned, is overhead from both a usability and maintainability perspective. I haven’t used jsonnet before but I know that cuelang gives you some power tools around typing, config validation, templating etc. it’s essentially purpose made for configuration management and tooling so it’s probably going to be really good at that. I don’t know if it’s worth using over a suite of language specific tools like Pydantic + Jinja though because when you’re using a general purpose language like python you have a whole, much larger ecosystem of tools and libraries you also have access to and can pull from.
Some drawbacks of plain YAML, and of tools that use string templating to render YAML:
- difficult to extend features not exposed by upstream
- composition is often messy, resulting in duplication
- validation is often impractical (at least identifying the exact source of the error… I’m looking at you Helm!)
Nope. Nope. Nope.
It’s like going back to Mongo without schemas and relational checks. We have perfectly good configuration languages with schemas, checks, imports, logic, etc. YAML is unacceptable in this profession.