optimize how xds bootstrap fills in default values for node.ClientFeatures

Author: clement2026

xds/googledirectpath/googlec2p_test.go

@@ -199,7 +199,7 @@ func TestBuildXDS(t *testing.T) {
 				Locality:             &v3corepb.Locality{Zone: testZone},
 				UserAgentName:        gRPCUserAgentName,
 				UserAgentVersionType: &v3corepb.Node_UserAgentVersion{UserAgentVersion: grpc.Version},
-				ClientFeatures:       []string{clientFeatureNoOverprovisioning},
+				ClientFeatures:       []string{clientFeatureNoOverprovisioning, clientFeatureResourceWrapper},
 			}
 			if tt.ipv6 {
 				wantNode.Metadata = &structpb.Struct{

xds/internal/xdsclient/bootstrap/bootstrap.go

@@ -565,7 +565,7 @@ func newConfigFromContents(data []byte) (*Config, error) {
 	}
 	node.UserAgentName = gRPCUserAgentName
 	node.UserAgentVersionType = &v3corepb.Node_UserAgentVersion{UserAgentVersion: grpc.Version}
-	node.ClientFeatures = append(node.ClientFeatures, clientFeatureNoOverprovisioning, clientFeatureResourceWrapper)
+	node.ClientFeatures = AppendIfNotPresent(node.ClientFeatures, clientFeatureNoOverprovisioning, clientFeatureResourceWrapper)
 	config.NodeProto = node
 
 	logger.Debugf("Bootstrap config for creating xds-client: %v", pretty.ToJSON(config))

xds/internal/xdsclient/bootstrap/utils.go

@@ -0,0 +1,36 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package bootstrap
+
+// AppendIfNotPresent adds elems to a slice while ignoring duplicates
+func AppendIfNotPresent[E comparable](slice []E, elems ...E) []E {
+	presented := make(map[E]struct{})
+
+	for _, s := range slice {
+		presented[s] = struct{}{}
+	}
+
+	for _, e := range elems {
+		if _, ok := presented[e]; !ok {
+			slice = append(slice, e)
+			presented[e] = struct{}{}
+		}
+	}
+	return slice
+}

xds/internal/xdsclient/bootstrap/utils_test.go

@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package bootstrap
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestAppendIfNotPresent(t *testing.T) {
+	type args struct {
+		slice []string
+		elems []string
+	}
+	tests := []struct {
+		name string
+		args args
+		want []string
+	}{
+		{name: "empty", args: args{[]string{}, []string{"a"}}, want: []string{"a"}},
+		{name: "just append", args: args{[]string{"a"}, []string{"b"}}, want: []string{"a", "b"}},
+		{name: "ignore a", args: args{[]string{"a"}, []string{"a", "b"}}, want: []string{"a", "b"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := AppendIfNotPresent(tt.args.slice, tt.args.elems...); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIfNotPresent() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}