examples: multiplex (#2477)

examples/features/multiplex/README.md

@@ -0,0 +1,12 @@
+# Multiplex
+
+A `grpc.ClientConn` can be shared by two stubs and two services can share a
+`grpc.Server`. This example illustrates how to perform both types of sharing.
+
+```
+go run server/main.go
+```
+
+```
+go run client/main.go
+```

examples/features/multiplex/client/main.go

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+/*
+ *
+ * Copyright 2018 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 main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"google.golang.org/grpc"
+	ecpb "google.golang.org/grpc/examples/features/proto/echo"
+	hwpb "google.golang.org/grpc/examples/helloworld/helloworld"
+)
+
+const (
+	address = "localhost:50051"
+)
+
+// callSayHello calls SayHello on c with the given name, and prints the
+// response.
+func callSayHello(c hwpb.GreeterClient, name string) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	r, err := c.SayHello(ctx, &hwpb.HelloRequest{Name: name})
+	if err != nil {
+		log.Fatalf("client.SayHello(_) = _, %v", err)
+	}
+	fmt.Println("Greeting: ", r.Message)
+}
+
+func callUnaryEcho(client ecpb.EchoClient, message string) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	resp, err := client.UnaryEcho(ctx, &ecpb.EchoRequest{Message: message})
+	if err != nil {
+		log.Fatalf("client.UnaryEcho(_) = _, %v: ", err)
+	}
+	fmt.Println("UnaryEcho: ", resp.Message)
+}
+
+func main() {
+	// Set up a connection to the server.
+	conn, err := grpc.Dial(address, grpc.WithInsecure())
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+	defer conn.Close()
+
+	fmt.Println("--- calling helloworld.Greeter/SayHello ---")
+	// Make a greeter client and send an RPC.
+	hwc := hwpb.NewGreeterClient(conn)
+	callSayHello(hwc, "multiplex")
+
+	fmt.Println()
+	fmt.Println("--- calling routeguide.RouteGuide/GetFeature ---")
+	// Make a routeguild client with the same ClientConn.
+	rgc := ecpb.NewEchoClient(conn)
+	callUnaryEcho(rgc, "this is examples/multiplex")
+}

examples/features/multiplex/server/main.go

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+/*
+ *
+ * Copyright 2018 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 main
+
+import (
+	"context"
+	"log"
+	"net"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	ecpb "google.golang.org/grpc/examples/features/proto/echo"
+	hwpb "google.golang.org/grpc/examples/helloworld/helloworld"
+	"google.golang.org/grpc/status"
+)
+
+const (
+	port = ":50051"
+)
+
+// hwServer is used to implement helloworld.GreeterServer.
+type hwServer struct{}
+
+// SayHello implements helloworld.GreeterServer
+func (s *hwServer) SayHello(ctx context.Context, in *hwpb.HelloRequest) (*hwpb.HelloReply, error) {
+	return &hwpb.HelloReply{Message: "Hello " + in.Name}, nil
+}
+
+type ecServer struct{}
+
+func (s *ecServer) UnaryEcho(ctx context.Context, req *ecpb.EchoRequest) (*ecpb.EchoResponse, error) {
+	return &ecpb.EchoResponse{Message: req.Message}, nil
+}
+
+func (s *ecServer) ServerStreamingEcho(*ecpb.EchoRequest, ecpb.Echo_ServerStreamingEchoServer) error {
+	return status.Errorf(codes.Unimplemented, "not implemented")
+}
+
+func (s *ecServer) ClientStreamingEcho(ecpb.Echo_ClientStreamingEchoServer) error {
+	return status.Errorf(codes.Unimplemented, "not implemented")
+}
+
+func (s *ecServer) BidirectionalStreamingEcho(ecpb.Echo_BidirectionalStreamingEchoServer) error {
+	return status.Errorf(codes.Unimplemented, "not implemented")
+}
+
+func main() {
+	lis, err := net.Listen("tcp", port)
+	if err != nil {
+		log.Fatalf("failed to listen: %v", err)
+	}
+	s := grpc.NewServer()
+
+	// Register Greeter on the server.
+	hwpb.RegisterGreeterServer(s, &hwServer{})
+
+	// Register RouteGuide on the same server.
+	ecpb.RegisterEchoServer(s, &ecServer{})
+
+	if err := s.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}