BUG: gRPC-message `bytes` field is ignored for OpenAPI and gateway

[WizMe-M]

Repro

1. Define some message with bytes field_name_1 = 1; or use the Any message from google/protobuf package.
2. Define service that uses this message in request/response
3. Map REST endpoint to gRPC service's rpc in gateway config
4. Create OpenAPI config and add that service
5. Generate

See that bytes field was cut out:

components:
  schemas:
    Any:
      type: object
      description: Any contains an arbitrary schema along with a URL to help identify the type of the schema.
      properties:
        '@type':
          type: string
          description: A URL/resource name that uniquely identifies the type of the schema.

Expected

• gRPC bytes field is converted into Base64 JSON-string by default (?) or OpenAPI config has option how to manage this.

Question

How to persist this field in message? How to specify what conversion should be used for this concrete bytes field?
Where is this conversion config should be managed: in OpenAPI/gateway config(s) or in grpc-gw implementation?

[WizMe-M]

This issue is related to issue #35

[WizMe-M]

Specifiying message description (to persist field value of Any) in openapi-config does nothing.
OpenAPI config spec:

openapi:
  messages: 
    - selector: .google.protobuf.Any
      schema: 
        description: custom
      fields: 
        value:
          description: My description of this field
          types:
            - STRING

Resulting OpenAPI yaml:

components:
  schemas:
    Any:
      type: object
      description: Any contains an arbitrary schema along with a URL to help identify the type of the schema.
      properties:
        '@type':
          type: string
          description: A URL/resource name that uniquely identifies the type of the schema.

It could be either missing support for well-known protobuf types or/and wrong selector for this type