Automatically annotate using x-go-type

[NPellet]

🚀 Feature

In a way I'm a bit surprised this hasn't been done / hasn't been requested.

Given the content of the proto file, it would be quite easy to generate the x-go-type annotation automatically for the OpenAPIv2 spec file, such that go-swagger can re-use the go type and not regenerate a new one. We use a monorepo, so for us this is super powerful.

I've managed to get it going using

option go_package = "<path/to/my/package>";

message <TypeName> {
   option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_schema) = {
        json_schema: {
          extensions: {
            key: "x-go-type"
            value: {
                struct_value: { 
                    fields: {
                        key: "type",
                        value: { string_value: "<TypeName>" }
                    },
                    fields: {
                        key: "import",
                        value: { 
                            struct_value: {
                                fields: {
                                    key: "package",
                                    value: { string_value: "<path/to/my/package>" }
                                } 
                            }
                        }
                    }
                }
            }
          }
        }
      }
}

So I guess I'm curious as to whether this was considered / rejected, and if PRs would be welcome here.

We wouldn't want to pollute JsonSchema of course, so I'd suggest this could go through another annotation.

[johanbrandhorst]

Hi Norman, thanks for your issue! I don't remember this having been requested before. I think it could make sense as a feature to save users having to supply these annotations themselves everywhere, but it should be behind a generator option, so it doesn't add annotations to users that don't want it. Would you be interested in helping implement this?

[NPellet]

A generator option would be everything or nothing, though... Oh well I guess it would be enough

But the problem I will hit while doing so is that go-swagger expects the type to implement Validate(formats strfmt.Registry) error (instead of interface-checking at runtime), while [protoc-gen-validate](https://github.com/bufbuild/protoc-gen-validate) provides Validate() error

Ah that's a bit annoying. Not directly related to this issue though. I'll see if I can get go-swagger to assert on the interface instead