libopenapi to generate the model not just from bytes , but from go code too

[chinglinwen]

from user point of view, I'm thinking what I'd like, hope this can bring some new ideas, or you can think of this as a feature request

a probable overview of the workflow:

1. write go struct

• define tag ( protobuf tag example ) ( may similar to deepcopy-gen , genearte an extra go file )
• or comments(kubebuilder marks)
• or multiline comments(swag, I don't much like this way though)

2. generate go code(an extra go file) (example openapi-gen)
3. generate the final model (document.BuildV3Model()) from go code ( example )
4. serve such json or yaml with http handler ( example )

some relate project I would like to libopenapi to be harmony with:

• https://google.aip.dev/
• https://github.com/googleapis/gapic-generator ( archived though )
• https://github.com/googleapis/gapic-showcase/blob/main/schema/google/showcase/v1beta1/messaging.proto ( example protobuf define http stuff )

I'm thinking how could these all could work together, some kubernetes tool may have narrow scope, this where libopenapi could comes in ( a general rest api tool, provide simple method to generate openapi )

one idea, writing openapi.yaml are error prone
and I'd expect all things go code ( abstract away the detail )
decompose things to go code, and so I can compose the whole spec definition from go code, so maybe it will be more maintainable ( the whole process )

[EwenQuim]

Trying to port Fuego to libopenapi.

Would love to have this feature, it would make the migration easier!

I might try to implement partially this feature for libopenapi

[daveshanley]

Please feel free to contribute! This feature isn't on my immediate roadmap (I have no use for it myself right now), your PR would be welcome.