[go-server] Support go custom tags

[andrewkav]

Description

Sometimes there is a necessity to add extra tags to generated models. For example when using validators based on go tags.
Example of generated code:

type SomeStruct struct {
	ID string `json:"id,omitempty" validate:"required"`
}

openapi-generator version

3.3.0

OpenAPI declaration file content or url

Command line used for generation

Steps to reproduce

Related issues/PRs

Suggest a fix/enhancement

Suggesting to use vendor extension x-go-custom-tag to include the tag into generated model
example of YAML

    SomeStruct:
      type: object
      properties:
        id:
          type: string
          x-go-custom-tag: validate:"required"

[mcdoker18]

@andrewkav I think you forgot to close the issue.
By the way, thank you for the feature!

[gothicfann]

Hello guys, this feature is not working for properties which are referencing other definitions. Please fix, it trivial for me.

[wing328]

when using $ref, i think everything else is ignored

[gothicfann]

@wing328 cant we fix this somehow, or maybe there is some workaround for this?

[gothicfann]

I need this feature to generate terraform provider after generating sdk.

[wing328]

my answer is according to the openapi spec so don't think we can support it somehow.

[gothicfann]

@wing328 It should not work also this way?

[gothicfann]

@wing328 please take a look above comment, I embedded referenced definition and it still does not work. without $ref

[gothicfann]

I think it does not work at all when there is object type...

[loispostula]

Hi @gothicfann, just wanted to add that if you put the tag on the $ref itself, it's working then

openapi: 3.0.3
info:
  title: API
  version: 1.0.0
  description: Custom API
paths: {}
components:
  schemas:
    RemoteObject:
      type: object
      properties:
        name:
          type: string
          maxLength: 100
          x-go-custom-tag: tfsdk:"name"
      
      x-go-custom-tag: tfsdk:"remote_object"
      required:
      - name
    CustomObject:
       type: object
       properties:
         name:
          type: string
          maxLength: 100
          x-go-custom-tag: tfsdk:"name"
         remote_object:
           $ref: "#/components/schemas/RemoteObject"
       required:
       - name
       - remote_object

Will generate the following go struct

// RemoteObject struct for RemoteObject
type RemoteObject struct {
	Name string `json:"name" tfsdk:"name"`
}

// CustomObject struct for CustomObject
type CustomObject struct {
	Name string `json:"name" tfsdk:"name"`
	RemoteObject RemoteObject `json:"remote_object" tfsdk:"remote_object"`
}