snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

examples/features/xds/README.md

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+# gRPC xDS example
+
+xDS is the protocol initially used by Envoy, that is evolving into a universal
+data plane API for service mesh.
+
+The xDS example is a Hello World client/server capable of being configured with
+the XDS management protocol. Out-of-the-box it behaves the same as [our other
+hello world
+example](https://github.com/grpc/grpc-go/tree/master/examples/helloworld). The
+server replies with responses including its hostname.
+
+## xDS environment setup
+
+This example doesn't include instructions to setup xDS environment. Please refer
+to documentation specific for your xDS management server. Examples will be added
+later.
+
+The client also needs a bootstrap file. See [gRFC
+A27](https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md#xdsclient-and-bootstrap-file)
+for the bootstrap format.
+
+## The client
+
+The client application needs to import the xDS package to install the resolver and balancers:
+
+```go
+_ "google.golang.org/grpc/xds" // To install the xds resolvers and balancers.
+```
+
+Then, use `xds` target scheme for the ClientConn.
+
+```
+$ export GRPC_XDS_BOOTSTRAP=/path/to/bootstrap.json
+$ go run client/main.go "xDS world" xds:///target_service
+```

examples/features/xds/client/main.go

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+/*
+ *
+ * Copyright 2020 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.
+ *
+ */
+
+// Binary main implements a client for Greeter service using gRPC's client-side
+// support for xDS APIs.
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"strings"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	xdscreds "google.golang.org/grpc/credentials/xds"
+	pb "google.golang.org/grpc/examples/helloworld/helloworld"
+
+	_ "google.golang.org/grpc/xds" // To install the xds resolvers and balancers.
+)
+
+var (
+	target   = flag.String("target", "xds:///localhost:50051", "uri of the Greeter Server, e.g. 'xds:///helloworld-service:8080'")
+	name     = flag.String("name", "world", "name you wished to be greeted by the server")
+	xdsCreds = flag.Bool("xds_creds", false, "whether the server should use xDS APIs to receive security configuration")
+)
+
+func main() {
+	flag.Parse()
+
+	if !strings.HasPrefix(*target, "xds:///") {
+		log.Fatalf("-target must use a URI with scheme set to 'xds'")
+	}
+
+	creds := insecure.NewCredentials()
+	if *xdsCreds {
+		log.Println("Using xDS credentials...")
+		var err error
+		if creds, err = xdscreds.NewClientCredentials(xdscreds.ClientOptions{FallbackCreds: insecure.NewCredentials()}); err != nil {
+			log.Fatalf("failed to create client-side xDS credentials: %v", err)
+		}
+	}
+	conn, err := grpc.NewClient(*target, grpc.WithTransportCredentials(creds))
+	if err != nil {
+		log.Fatalf("grpc.NewClient(%s) failed: %v", *target, err)
+	}
+	defer conn.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	c := pb.NewGreeterClient(conn)
+	r, err := c.SayHello(ctx, &pb.HelloRequest{Name: *name})
+	if err != nil {
+		log.Fatalf("could not greet: %v", err)
+	}
+	log.Printf("Greeting: %s", r.GetMessage())
+}

examples/features/xds/server/main.go

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+/*
+ *
+ * Copyright 2020 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.
+ *
+ */
+
+// Binary server demonstrated gRPC's support for xDS APIs on the server-side. It
+// exposes the Greeter service that will response with the hostname.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	rand "math/rand/v2"
+	"net"
+	"os"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	xdscreds "google.golang.org/grpc/credentials/xds"
+	pb "google.golang.org/grpc/examples/helloworld/helloworld"
+	"google.golang.org/grpc/health"
+	healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/xds"
+)
+
+var (
+	port     = flag.Int("port", 50051, "the port to serve Greeter service requests on. Health service will be served on `port+1`")
+	xdsCreds = flag.Bool("xds_creds", false, "whether the server should use xDS APIs to receive security configuration")
+)
+
+// server implements helloworld.GreeterServer interface.
+type server struct {
+	pb.UnimplementedGreeterServer
+	serverName string
+}
+
+// SayHello implements helloworld.GreeterServer interface.
+func (s *server) SayHello(_ context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
+	log.Printf("Received: %v", in.GetName())
+	return &pb.HelloReply{Message: "Hello " + in.GetName() + ", from " + s.serverName}, nil
+}
+
+func determineHostname() string {
+	hostname, err := os.Hostname()
+	if err != nil {
+		log.Printf("Failed to get hostname: %v, will generate one", err)
+		return fmt.Sprintf("generated-%03d", rand.Int()%100)
+	}
+	return hostname
+}
+
+func main() {
+	flag.Parse()
+
+	greeterPort := fmt.Sprintf(":%d", *port)
+	greeterLis, err := net.Listen("tcp4", greeterPort)
+	if err != nil {
+		log.Fatalf("net.Listen(tcp4, %q) failed: %v", greeterPort, err)
+	}
+
+	creds := insecure.NewCredentials()
+	if *xdsCreds {
+		log.Println("Using xDS credentials...")
+		var err error
+		if creds, err = xdscreds.NewServerCredentials(xdscreds.ServerOptions{FallbackCreds: insecure.NewCredentials()}); err != nil {
+			log.Fatalf("failed to create server-side xDS credentials: %v", err)
+		}
+	}
+
+	greeterServer, err := xds.NewGRPCServer(grpc.Creds(creds))
+	if err != nil {
+		log.Fatalf("Failed to create an xDS enabled gRPC server: %v", err)
+	}
+	pb.RegisterGreeterServer(greeterServer, &server{serverName: determineHostname()})
+
+	healthPort := fmt.Sprintf(":%d", *port+1)
+	healthLis, err := net.Listen("tcp4", healthPort)
+	if err != nil {
+		log.Fatalf("net.Listen(tcp4, %q) failed: %v", healthPort, err)
+	}
+	grpcServer := grpc.NewServer()
+	healthServer := health.NewServer()
+	healthServer.SetServingStatus("", healthpb.HealthCheckResponse_SERVING)
+	healthgrpc.RegisterHealthServer(grpcServer, healthServer)
+
+	log.Printf("Serving GreeterService on %s and HealthService on %s", greeterLis.Addr().String(), healthLis.Addr().String())
+	go func() {
+		greeterServer.Serve(greeterLis)
+	}()
+	grpcServer.Serve(healthLis)
+}