gen-swagger does not generate PATCH method endpoints

[sdemos]

The grpc-gateway generator correctly generates working endpoints using the patch method, but the swagger generator just outputs empty data for those paths.

For example:

service ExampleService {
    rpc SetAppLabel(SetAppLabelReq) returns (SetAppLabelResp) {
        option (google.api.http) = {
            patch: "/apps/{id}/label"
            body: "*"
        };
    }
}

message SetAppLabelReq {
    string id = 1;
    string label = 2;
}

message SetAppLabelResp{
    string id = 1;
}

generates a path that looks like this:

  '/apps/{id}/label": {}

instead of generating the correct swagger output, which would be something like this:

  '/apps/{id}/label':
    patch:
      operationId: SetAppLabel
      responses:
        '200':
          description: ''
          schema:
            $ref: '#/definitions/protoSetAppLabelResp'
      parameters:
        - name: id
          in: path
          required: true
          type: string
          format: string
        - name: body
          in: body
          required: true
          schema:
            $ref: '#/definitions/protoSetAppLabelReq'

[ericlagergren]

AFAICT the patch is fairly simple:

diff --git a/protoc-gen-swagger/genswagger/template.go b/protoc-gen-swagger/genswagger/template.go
index d33aba5..9db445c 100644
--- a/protoc-gen-swagger/genswagger/template.go
+++ b/protoc-gen-swagger/genswagger/template.go
@@ -437,6 +437,9 @@ func renderServices(services []*descriptor.Service, paths swaggerPathsObject, re
                case "PUT":
                    pathItemObject.Put = operationObject
                    break
+               case "PATCH":
+                   pathItemObject.Patch = operationObject
+                   break
                }
                paths[templateToSwaggerPath(b.PathTmpl.Template)] = pathItemObject
            }
diff --git a/protoc-gen-swagger/genswagger/types.go b/protoc-gen-swagger/genswagger/types.go
index b91e457..a31f3ec 100644
--- a/protoc-gen-swagger/genswagger/types.go
+++ b/protoc-gen-swagger/genswagger/types.go
@@ -66,6 +66,7 @@ type swaggerPathItemObject struct {
    Delete *swaggerOperationObject `json:"delete,omitempty"`
    Post   *swaggerOperationObject `json:"post,omitempty"`
    Put    *swaggerOperationObject `json:"put,omitempty"`
+   Patch  *swaggerOperationObject `json:"patch,omitempty"`
 }

 // http://swagger.io/specification/#operationObject

[achew22]

That looks like a really great start! Do you think you could turn that into a pull request and send it in? Thanks so much