Exclude private API calls from swagger (grpc-ecosystem#7)

* add generation second file with  private methods

* update logic

* update README.md

* remove private definitions

protoc-gen-grpc-gateway/descriptor/registry.go

@@ -47,6 +47,9 @@ type Registry struct {
 	// atlasPatch ...
 	atlasPatch bool
 
+	//withPrivateOperations if true exclude all operations with tag "private"
+	withPrivateOperations bool
+
 	// mergeFileName target swagger file name after merge
 	mergeFileName string
 }
@@ -325,6 +328,15 @@ func (r *Registry) SetAtlasPatch(atlas bool) {
 	r.atlasPatch = atlas
 }
 
+// IsWithPrivateOperations if true exclude all operations with tag "private"
+func (r *Registry) IsWithPrivateOperations() bool {
+	return r.withPrivateOperations
+}
+
+func (r *Registry) SetWithPrivateOperations(withPrivateOperations bool) {
+	r.withPrivateOperations = withPrivateOperations
+}
+
 // SetMergeFileName controls the target swagger file name out of multiple protos
 func (r *Registry) SetMergeFileName(mergeFileName string) {
 	r.mergeFileName = mergeFileName

protoc-gen-swagger/README.md

@@ -27,4 +27,24 @@ Patch includes following changes:
      query parameters, also id.payload_id is replaced with id in path.
 
    * Unused references elimination.
-
+
+   * Exclude all operations tagged as "private" see example below
+       ```
+       rpc Update (UpdateNetworkRequest) returns (UpdateNetworkResponse) {
+           option (google.api.http) = {
+             put: "/network/{payload.id.resource_id}"
+             body: "payload"
+       
+             additional_bindings {
+               patch: "/network/{payload.id.resource_id}",
+               body:  "payload"
+             }
+       
+           };
+           option (grpc.gateway.protoc_gen_swagger.options.openapiv2_operation) = {
+             tags: "private"
+           };
+         }
+       ```
+   * Introduced new `with_private` flag if set generate service.private.swagger.json
+   with all operation (including tagged as "private")