Warn user in case an OpenAPI description with inline schema is provided as input

[LorenzHW]

Regarding Tim's comment:

Since schema references often correspond to named structs, I'm inclined to force all inlined schemas to be converted to references, either with a linter rule or a transformation.

As long as this linter rule or transformation does not exist we should display a warning that the output of gnostic-grpc might be faulty in case the user provides an OpenAPI description with inline schemas.

Example input API with inline schema:

paths:
  /inlineSchema:
    get:
      operationId: inlineSchema
      responses:
        200:
          description: succes
          content:
            application/json:
              schema:
                type: integer
                format: int32

Expected console output after running gnostic --grpc-out...:

level:WARNING  code: "" text: "An inline schema is provided. The output of gnostic-grpc might be incorrect. Consider using a reference for your schema" keys:"paths" keys:"/inlineSchema" keys:"get" keys:"responses" keys:"200" keys:"content" keys:"application/json" keys:"schema"

Example input API with reference schema:

paths:
  /referenceSchema:
    get:
      operationId: referenceSchema
      responses:
        200:
          description: success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Person'
components:
  schemas:
    Person:
      type: object
      properties:
        age:
          type: integer
          format: int64
        name:
          type: string
          example: Peter

Expected console output:
No warning regarding inline schema

[LorenzHW]

@idoqo do you want to work on this?

[idoqo]

Yeah. I'd like to love to work on this one.

[LorenzHW]

Cool! LMK in case you have any questions.

[idoqo]

Hi, sorry...I was wondering what would be the best way to check if a schema in the description is inline (or referenced) as it seems to be abstracted out by the SchemasOrReference, ResponsesOrReferences, etc by gnostic.

[LorenzHW]

Hi. Sorry for the late response.

Yes, exactly. The function anaylzeSchema(.., schemaOrReference *openapiv3.SchemaOrReference, ..) has as input a schemaOrReference. Now, you can use the methods: schemaOrReference.GetSchema() and schemaOrReference.GetReference(). One of these functions will return something and the other one will return nil. Then you probably need some kind of check whether you are currently analyzing the paths section of the OpenAPI document. If that is the case AND schemaOrReference.GetSchema() does return a schema, a warning needs to be constructed. Does this help?

[idoqo]

Does this help?

Yes, it does a lot. I'd work with that then, thanks a lot.