openapiv2: Field options are not properly rendered for repeated fields

[sumabn]

I need to generate swagger json using proto annotations.
generated schema should look like this

"schema": {
              "type": "object",
              "example": {
                "product_id": ["8900099100000113079", "8900099100000082373"]
              },
              "properties": {
                "product_id": {
                  "type": "array",
                  "items": {
                    "type": "string",
                    "maxLength": 19,
                   "minLength": 1,
                   "pattern": "^[0-9]+$"
                  },
                  "description": "Only digits are allowed.",
                  "title": "Provide list of ids"           
                }
              }
            }

and the annotation added was something like this

message product { 
repeated string product_id=1[(grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
                  pattern: "^[0-9]+$"
                  max_length: 19
                  min_length: 1
                  description: "Only digits are allowed."
    }];
}

But the problem is above annotation is generating schema like this

"schema": {
              "type": "object",
              "example": {
                "product_id": ["8900099100000113079", "8900099100000082373"]
              },
              "properties": {
                "product_id": {
                  "type": "array",
                  "items": {
                    "type": "string"                   
                  },
                  "description": "Only digits are allowed.",
                  "title": "Provide list of ids",
                   "maxLength": 19,
                   "minLength": 1,
                   "pattern": "^[0-9]+$"           
                }
              }
            }

which is not correct. We could not find the relevant example in a_bit_of_everything.proto.

Please help in adding the annotations.

[johanbrandhorst]

Hi! I went and looked at the OpenAPIv2 spec and it seems you can specify the field properties both at the top level and inside the items object: https://swagger.io/specification/v2/#items-object. I think we should probably put it inside the items if the specified field is repeated. Would you be willing to help contribute a fix for this?

The easiest way to get started would be to add a new test to https://github.com/grpc-ecosystem/grpc-gateway/blob/master/protoc-gen-openapiv2/internal/genopenapi/template_test.go that would have the expected behavior. Having had a quick glance at the code, I think you'll need to make the changes here:

grpc-gateway/protoc-gen-openapiv2/internal/genopenapi/template.go

Line 398 in bfda18d

func renderMessageAsDefinition(msg *descriptor.Message, reg *descriptor.Registry, customRefs refMap, excludeFields []*descriptor.Field) openapiSchemaObject {

, but I could be wrong.

[lakshkeswani]

/assign @johanbrandhorst i am willing to contribute on this kindly assign it to me

[johanbrandhorst]

Hi @lakshkeswani, please have at it!

[jan-sykora]

We're dealing with similar issue. Our proto file:

import "google/protobuf/field_mask.proto";

message SomeMessage {
  google.protobuf.FieldMask update_mask = 10;
}

(Here's the definition of FieldMask:)

// google/protobuf/field_mask.proto

message FieldMask {
  // The set of field mask paths.
  repeated string paths = 1;
}

is generated into openapiv2 spec as:

"parameters": [
  {
    "name": "updateMask",
    "in": "query",
    "type": "string"
  }
]

The issue is that FieldMask should be generated into OpenAPI as a "type": "array" (expected) but it is generated as a "type": "string" (actual).

[johanbrandhorst]

This sounds like a separate issue, could you create a separate issue and share your RPC definition too please?

[jan-sykora]

@johanbrandhorst I have created a separate issue #2580 with reproducible example.