Merge pull request #130 from thaJeztah/18.09_backport_fix_api_return_code

[18.09 backport] API: fix status code on conflicting service names
Upstream-commit: 42b58273f68c8240e25f1642e6add6435b894e87
Component: engine

components/engine/vendor/github.com/docker/swarmkit/manager/controlapi/service.go

@@ -680,13 +680,14 @@ func (s *Server) CreateService(ctx context.Context, request *api.CreateServiceRe
 
 		return store.CreateService(tx, service)
 	})
-	if err != nil {
+	switch err {
+	case store.ErrNameConflict:
+		return nil, status.Errorf(codes.AlreadyExists, "service %s already exists", request.Spec.Annotations.Name)
+	case nil:
+		return &api.CreateServiceResponse{Service: service}, nil
+	default:
 		return nil, err
 	}
-
-	return &api.CreateServiceResponse{
-		Service: service,
-	}, nil
 }
 
 // GetService returns a Service given a ServiceID.
@@ -896,7 +897,12 @@ func (s *Server) ListServices(ctx context.Context, request *api.ListServicesRequ
 		}
 	})
 	if err != nil {
-		return nil, err
+		switch err {
+		case store.ErrInvalidFindBy:
+			return nil, status.Errorf(codes.InvalidArgument, err.Error())
+		default:
+			return nil, err
+		}
 	}
 
 	if request.Filters != nil {