Support schema export

[airwoodix]

Is there tooling or preliminary work looking into exporting a schema for the settings described by miniconf?

In particular for MQTT, something like asyncapi could be nice and provide a way to automatically document the settings.

[jordens]

Not that I'm aware of.

[jordens]

Easiest approach is probably to co-derive with schemars matching skip, rename etc. and then transform or re-interpret.

[airwoodix]

Thanks for the feedback! The interaction with schemars sounds promising. I guess one could start with being able to derive from JsonSchema, and handle the actual schema output separately?

For the JsonSchema derivation: one could rely on schemars' serde compatibilty to write something like:

#[derive(JsonSchema, Tree)]
struct Settings {
    #[serde(skip)] // or #[schemars(skip)]
    #[tree(skip)]
    foo: Leaf<bool>,
    // ...
}

but the duplication is ugly and even more annoying for rename.

The easy way around would be to forward the serde or schemars attributes to the Tree derive, but that would heavily break the existing API. Writing the schemars/serde attributes from the tree ones won't work with a derive macro (but with an attribute one). Optionally adding the JsonSchema implementation as Tree derive is not so easy, because the implementation functions are not exported by schemars.

Do you see nicer ways than what's outlined above?