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

examples/features/authentication/client/main.go

@@ -0,0 +1,86 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+// The client demonstrates how to supply an OAuth2 token for every RPC.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"golang.org/x/oauth2"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/oauth"
+	"google.golang.org/grpc/examples/data"
+	ecpb "google.golang.org/grpc/examples/features/proto/echo"
+)
+
+var addr = flag.String("addr", "localhost:50051", "the address to connect to")
+
+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() {
+	flag.Parse()
+
+	// Set up the credentials for the connection.
+	perRPC := oauth.TokenSource{TokenSource: oauth2.StaticTokenSource(fetchToken())}
+	creds, err := credentials.NewClientTLSFromFile(data.Path("x509/ca_cert.pem"), "x.test.example.com")
+	if err != nil {
+		log.Fatalf("failed to load credentials: %v", err)
+	}
+	opts := []grpc.DialOption{
+		// In addition to the following grpc.DialOption, callers may also use
+		// the grpc.CallOption grpc.PerRPCCredentials with the RPC invocation
+		// itself.
+		// See: https://godoc.org/google.golang.org/grpc#PerRPCCredentials
+		grpc.WithPerRPCCredentials(perRPC),
+		// oauth.TokenSource requires the configuration of transport
+		// credentials.
+		grpc.WithTransportCredentials(creds),
+	}
+
+	conn, err := grpc.NewClient(*addr, opts...)
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+	defer conn.Close()
+	rgc := ecpb.NewEchoClient(conn)
+
+	callUnaryEcho(rgc, "hello world")
+}
+
+// fetchToken simulates a token lookup and omits the details of proper token
+// acquisition. For examples of how to acquire an OAuth2 token, see:
+// https://godoc.org/golang.org/x/oauth2
+func fetchToken() *oauth2.Token {
+	return &oauth2.Token{
+		AccessToken: "some-secret-token",
+	}
+}