xds: add new fields to XDSConfig (#3100)

Fields are added in: grpc/grpc-proto#64

Other changes:
 - Move XDSConfig from internal to balancer
   - Later we will add a separate config for CDS balancer
 - generate service_config.pb.go and test with json generated from proto message

internal/proto/grpc_service_config/example_test.go

@@ -0,0 +1,59 @@
+/*
+ *
+ * Copyright 2019 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.
+ */
+
+//go:generate ./regenerate.sh
+
+package grpc_service_config_test
+
+import (
+	"testing"
+
+	"github.com/golang/protobuf/jsonpb"
+	wrapperspb "github.com/golang/protobuf/ptypes/wrappers"
+	scpb "google.golang.org/grpc/internal/proto/grpc_service_config"
+)
+
+// TestXdsConfigMarshalToJSON is an example to print json format of xds_config.
+func TestXdsConfigMarshalToJSON(t *testing.T) {
+	c := &scpb.XdsConfig{
+		ChildPolicy: []*scpb.LoadBalancingConfig{
+			{Policy: &scpb.LoadBalancingConfig_Grpclb{
+				Grpclb: &scpb.GrpcLbConfig{},
+			}},
+			{Policy: &scpb.LoadBalancingConfig_RoundRobin{
+				RoundRobin: &scpb.RoundRobinConfig{},
+			}},
+		},
+		FallbackPolicy: []*scpb.LoadBalancingConfig{
+			{Policy: &scpb.LoadBalancingConfig_Grpclb{
+				Grpclb: &scpb.GrpcLbConfig{},
+			}},
+			{Policy: &scpb.LoadBalancingConfig_PickFirst{
+				PickFirst: &scpb.PickFirstConfig{},
+			}},
+		},
+		EdsServiceName: "eds.service.name",
+		LrsLoadReportingServerName: &wrapperspb.StringValue{
+			Value: "lrs.server.name",
+		},
+	}
+	j, err := (&jsonpb.Marshaler{}).MarshalToString(c)
+	if err != nil {
+		t.Fatalf("failed to marshal proto to json: %v", err)
+	}
+	t.Logf(j)
+}

internal/proto/grpc_service_config/regenerate.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+# Copyright 2019 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.
+
+set -eux -o pipefail
+
+TMP=$(mktemp -d)
+
+function finish {
+  rm -rf "$TMP"
+}
+trap finish EXIT
+
+pushd "$TMP"
+mkdir -p grpc/service_config
+curl https://raw.githubusercontent.com/grpc/grpc-proto/master/grpc/service_config/service_config.proto > grpc/service_config/service_config.proto
+mkdir -p google/rpc
+curl https://raw.githubusercontent.com/googleapis/googleapis/master/google/rpc/code.proto > google/rpc/code.proto
+
+protoc --go_out=plugins=grpc,paths=source_relative:. -I. grpc/service_config/*.proto
+popd
+rm -f ./*.pb.go
+cp "$TMP"/grpc/service_config/*.pb.go ./
+