func (s *testServer) UnaryCall(ctx context.Context, in *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
	md, ok := metadata.FromContext(ctx)
	if ok {
		if err := grpc.SendHeader(ctx, md); err != nil {
			grpclog.Fatalf("grpc.SendHeader(%v, %v) = %v, want %v", ctx, md, err, nil)
		}
		grpc.SetTrailer(ctx, md)
	}
	if s.security != "" {
		// Check Auth info
		authInfo, ok := credentials.FromContext(ctx)
		if !ok {
			grpclog.Fatalf("Failed to get AuthInfo from ctx.")
		}
		var authType string
		switch info := authInfo.(type) {
		case credentials.TLSInfo:
			authType = info.AuthType()
		default:
			grpclog.Fatalf("Unknown AuthInfo type")
		}
		if authType != s.security {
			grpclog.Fatalf("Wrong auth type: got %q, want %q", authType, s.security)
		}
	}

	// Simulate some service delay.
	time.Sleep(time.Second)
	return &testpb.SimpleResponse{
		Payload: newPayload(in.GetResponseType(), in.GetResponseSize()),
	}, nil
}

func doCancelAfterFirstResponse(tc testpb.TestServiceClient) {
	ctx, cancel := context.WithCancel(context.Background())
	stream, err := tc.FullDuplexCall(ctx)
	if err != nil {
		grpclog.Fatalf("%v.FullDuplexCall(_) = _, %v", tc, err)
	}
	respParam := []*testpb.ResponseParameters{
		{
			Size: proto.Int32(31415),
		},
	}
	pl := newPayload(testpb.PayloadType_COMPRESSABLE, 27182)
	req := &testpb.StreamingOutputCallRequest{
		ResponseType:       testpb.PayloadType_COMPRESSABLE.Enum(),
		ResponseParameters: respParam,
		Payload:            pl,
	}
	if err := stream.Send(req); err != nil {
		grpclog.Fatalf("%v.Send(%v) = %v", stream, req, err)
	}
	if _, err := stream.Recv(); err != nil {
		grpclog.Fatalf("%v.Recv() = %v", stream, err)
	}
	cancel()
	if _, err := stream.Recv(); grpc.Code(err) != codes.Canceled {
		grpclog.Fatalf("%v compleled with error code %d, want %d", stream, grpc.Code(err), codes.Canceled)
	}
	grpclog.Println("CancelAfterFirstResponse done")
}

// RegisterService register a service and its implementation to the gRPC
// server. Called from the IDL generated code. This must be called before
// invoking Serve.
func (s *Server) RegisterService(sd *ServiceDesc, ss interface{}) {
	s.mu.Lock()
	defer s.mu.Unlock()
	// Does some sanity checks.
	if _, ok := s.m[sd.ServiceName]; ok {
		grpclog.Fatalf("grpc: Server.RegisterService found duplicate service registration for %q", sd.ServiceName)
	}
	ht := reflect.TypeOf(sd.HandlerType).Elem()
	st := reflect.TypeOf(ss)
	if !st.Implements(ht) {
		grpclog.Fatalf("grpc: Server.RegisterService found the handler of type %v that does not satisfy %v", st, ht)
	}
	srv := &service{
		server: ss,
		md:     make(map[string]*MethodDesc),
		sd:     make(map[string]*StreamDesc),
	}
	for i := range sd.Methods {
		d := &sd.Methods[i]
		srv.md[d.MethodName] = d
	}
	for i := range sd.Streams {
		d := &sd.Streams[i]
		srv.sd[d.StreamName] = d
	}
	s.m[sd.ServiceName] = srv
}

func doPerRPCCreds(tc testpb.TestServiceClient) {
	jsonKey := getServiceAccountJSONKey()
	pl := newPayload(testpb.PayloadType_COMPRESSABLE, largeReqSize)
	req := &testpb.SimpleRequest{
		ResponseType:   testpb.PayloadType_COMPRESSABLE.Enum(),
		ResponseSize:   proto.Int32(int32(largeRespSize)),
		Payload:        pl,
		FillUsername:   proto.Bool(true),
		FillOauthScope: proto.Bool(true),
	}
	token := getToken()
	kv := map[string]string{"authorization": token.TokenType + " " + token.AccessToken}
	ctx := metadata.NewContext(context.Background(), metadata.MD{"authorization": []string{kv["authorization"]}})
	reply, err := tc.UnaryCall(ctx, req)
	if err != nil {
		grpclog.Fatal("/TestService/UnaryCall RPC failed: ", err)
	}
	user := reply.GetUsername()
	scope := reply.GetOauthScope()
	if !strings.Contains(string(jsonKey), user) {
		grpclog.Fatalf("Got user name %q which is NOT a substring of %q.", user, jsonKey)
	}
	if !strings.Contains(*oauthScope, scope) {
		grpclog.Fatalf("Got OAuth scope %q which is NOT a substring of %q.", scope, *oauthScope)
	}
	grpclog.Println("PerRPCCreds done")
}

func doClientStreaming(tc testpb.TestServiceClient) {
	stream, err := tc.StreamingInputCall(context.Background())
	if err != nil {
		grpclog.Fatalf("%v.StreamingInputCall(_) = _, %v", tc, err)
	}
	var sum int
	for _, s := range reqSizes {
		pl := newPayload(testpb.PayloadType_COMPRESSABLE, s)
		req := &testpb.StreamingInputCallRequest{
			Payload: pl,
		}
		if err := stream.Send(req); err != nil {
			grpclog.Fatalf("%v.Send(%v) = %v", stream, req, err)
		}
		sum += s
		grpclog.Printf("Sent a request of size %d, aggregated size %d", s, sum)

	}
	reply, err := stream.CloseAndRecv()
	if err != nil {
		grpclog.Fatalf("%v.CloseAndRecv() got error %v, want %v", stream, err, nil)
	}
	if reply.GetAggregatedPayloadSize() != int32(sum) {
		grpclog.Fatalf("%v.CloseAndRecv().GetAggregatePayloadSize() = %v; want %v", stream, reply.GetAggregatedPayloadSize(), sum)
	}
	grpclog.Println("ClientStreaming done")
}

// loadFeatures loads features from a JSON file.
func (s *routeGuideServer) loadFeatures(filePath string) {
	file, err := ioutil.ReadFile(filePath)
	if err != nil {
		grpclog.Fatalf("Failed to load default features: %v", err)
	}
	if err := json.Unmarshal(file, &s.savedFeatures); err != nil {
		grpclog.Fatalf("Failed to load default features: %v", err)
	}
}

func getToken() *oauth2.Token {
	jsonKey := getServiceAccountJSONKey()
	config, err := google.JWTConfigFromJSON(jsonKey, *oauthScope)
	if err != nil {
		grpclog.Fatalf("Failed to get the config: %v", err)
	}
	token, err := config.TokenSource(context.Background()).Token()
	if err != nil {
		grpclog.Fatalf("Failed to get the token: %v", err)
	}
	return token
}

func doCancelAfterBegin(tc testpb.TestServiceClient) {
	ctx, cancel := context.WithCancel(metadata.NewContext(context.Background(), testMetadata))
	stream, err := tc.StreamingInputCall(ctx)
	if err != nil {
		grpclog.Fatalf("%v.StreamingInputCall(_) = _, %v", tc, err)
	}
	cancel()
	_, err = stream.CloseAndRecv()
	if grpc.Code(err) != codes.Canceled {
		grpclog.Fatalf("%v.CloseAndRecv() got error code %d, want %d", stream, grpc.Code(err), codes.Canceled)
	}
	grpclog.Println("CancelAfterBegin done")
}

func doEmptyStream(tc testpb.TestServiceClient) {
	stream, err := tc.FullDuplexCall(context.Background())
	if err != nil {
		grpclog.Fatalf("%v.FullDuplexCall(_) = _, %v", tc, err)
	}
	if err := stream.CloseSend(); err != nil {
		grpclog.Fatalf("%v.CloseSend() got %v, want %v", stream, err, nil)
	}
	if _, err := stream.Recv(); err != io.EOF {
		grpclog.Fatalf("%v failed to complete the empty stream test: %v", stream, err)
	}
	grpclog.Println("Emptystream done")
}

func runStream(b *testing.B, maxConcurrentCalls int) {
	s := stats.AddStats(b, 38)
	b.StopTimer()
	target, stopper := StartServer("localhost:0")
	defer stopper()
	conn := NewClientConn(target)
	tc := testpb.NewTestServiceClient(conn)

	// Warm up connection.
	stream, err := tc.StreamingCall(context.Background())
	if err != nil {
		grpclog.Fatalf("%v.StreamingCall(_) = _, %v", tc, err)
	}
	for i := 0; i < 10; i++ {
		streamCaller(tc, stream)
	}

	ch := make(chan int, maxConcurrentCalls*4)
	var (
		mu sync.Mutex
		wg sync.WaitGroup
	)
	wg.Add(maxConcurrentCalls)

	// Distribute the b.N calls over maxConcurrentCalls workers.
	for i := 0; i < maxConcurrentCalls; i++ {
		go func() {
			stream, err := tc.StreamingCall(context.Background())
			if err != nil {
				grpclog.Fatalf("%v.StreamingCall(_) = _, %v", tc, err)
			}
			for _ = range ch {
				start := time.Now()
				streamCaller(tc, stream)
				elapse := time.Since(start)
				mu.Lock()
				s.Add(elapse)
				mu.Unlock()
			}
			wg.Done()
		}()
	}
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		ch <- i
	}
	b.StopTimer()
	close(ch)
	wg.Wait()
	conn.Close()
}

// DoStreamingRoundTrip performs a round trip for a single streaming rpc.
func DoStreamingRoundTrip(tc testpb.TestServiceClient, stream testpb.TestService_StreamingCallClient, reqSize, respSize int) {
	pl := newPayload(testpb.PayloadType_COMPRESSABLE, reqSize)
	req := &testpb.SimpleRequest{
		ResponseType: pl.Type,
		ResponseSize: int32(respSize),
		Payload:      pl,
	}
	if err := stream.Send(req); err != nil {
		grpclog.Fatalf("StreamingCall(_).Send: %v", err)
	}
	if _, err := stream.Recv(); err != nil {
		grpclog.Fatalf("StreamingCall(_).Recv: %v", err)
	}
}

func main() {
	flag.Parse()
	go func() {
		lis, err := net.Listen("tcp", ":0")
		if err != nil {
			grpclog.Fatalf("Failed to listen: %v", err)
		}
		grpclog.Println("Client profiling address: ", lis.Addr().String())
		if err := http.Serve(lis, nil); err != nil {
			grpclog.Fatalf("Failed to serve: %v", err)
		}
	}()
	closeLoop()
}

func setUp(hs *health.HealthServer, maxStream uint32, ua string, e env) (s *grpc.Server, cc *grpc.ClientConn) {
	sopts := []grpc.ServerOption{grpc.MaxConcurrentStreams(maxStream)}
	la := ":0"
	switch e.network {
	case "unix":
		la = "/tmp/testsock" + fmt.Sprintf("%d", time.Now())
		syscall.Unlink(la)
	}
	lis, err := net.Listen(e.network, la)
	if err != nil {
		grpclog.Fatalf("Failed to listen: %v", err)
	}
	if e.security == "tls" {
		creds, err := credentials.NewServerTLSFromFile(tlsDir+"server1.pem", tlsDir+"server1.key")
		if err != nil {
			grpclog.Fatalf("Failed to generate credentials %v", err)
		}
		sopts = append(sopts, grpc.Creds(creds))
	}
	s = grpc.NewServer(sopts...)
	if hs != nil {
		healthpb.RegisterHealthCheckServer(s, hs)
	}
	testpb.RegisterTestServiceServer(s, &testServer{security: e.security})
	go s.Serve(lis)
	addr := la
	switch e.network {
	case "unix":
	default:
		_, port, err := net.SplitHostPort(lis.Addr().String())
		if err != nil {
			grpclog.Fatalf("Failed to parse listener address: %v", err)
		}
		addr = "localhost:" + port
	}
	if e.security == "tls" {
		creds, err := credentials.NewClientTLSFromFile(tlsDir+"ca.pem", "x.test.youtube.com")
		if err != nil {
			grpclog.Fatalf("Failed to create credentials %v", err)
		}
		cc, err = grpc.Dial(addr, grpc.WithTransportCredentials(creds), grpc.WithDialer(e.dialer), grpc.WithUserAgent(ua))
	} else {
		cc, err = grpc.Dial(addr, grpc.WithDialer(e.dialer), grpc.WithInsecure(), grpc.WithUserAgent(ua))
	}
	if err != nil {
		grpclog.Fatalf("Dial(%q) = %v", addr, err)
	}
	return
}

// NewClientConn creates a gRPC client connection to addr.
func NewClientConn(addr string) *grpc.ClientConn {
	conn, err := grpc.Dial(addr, grpc.WithInsecure())
	if err != nil {
		grpclog.Fatalf("NewClientConn(%q) failed to create a ClientConn %v", addr, err)
	}
	return conn
}

func (s *testServer) FullDuplexCall(stream testpb.TestService_FullDuplexCallServer) error {
	md, ok := metadata.FromContext(stream.Context())
	if ok {
		if err := stream.SendHeader(md); err != nil {
			grpclog.Fatalf("%v.SendHeader(%v) = %v, want %v", stream, md, err, nil)
		}
		stream.SetTrailer(md)
	}
	for {
		in, err := stream.Recv()
		if err == io.EOF {
			// read done.
			return nil
		}
		if err != nil {
			return err
		}
		cs := in.GetResponseParameters()
		for _, c := range cs {
			if us := c.GetIntervalUs(); us > 0 {
				time.Sleep(time.Duration(us) * time.Microsecond)
			}
			if err := stream.Send(&testpb.StreamingOutputCallResponse{
				Payload: newPayload(in.GetResponseType(), c.GetSize()),
			}); err != nil {
				return err
			}
		}
	}
}

func getServiceAccountJSONKey() []byte {
	jsonKey, err := ioutil.ReadFile(*serviceAccountKeyFile)
	if err != nil {
		grpclog.Fatalf("Failed to read the service account key file: %v", err)
	}
	return jsonKey
}

// start starts server. Other goroutines should block on s.readyChan for futher operations.
func (s *server) start(port int, maxStreams uint32, ht hType) {
	var err error
	if port == 0 {
		s.lis, err = net.Listen("tcp", ":0")
	} else {
		s.lis, err = net.Listen("tcp", ":"+strconv.Itoa(port))
	}
	if err != nil {
		grpclog.Fatalf("failed to listen: %v", err)
	}
	_, p, err := net.SplitHostPort(s.lis.Addr().String())
	if err != nil {
		grpclog.Fatalf("failed to parse listener address: %v", err)
	}
	s.port = p
	s.conns = make(map[ServerTransport]bool)
	if s.readyChan != nil {
		close(s.readyChan)
	}
	for {
		conn, err := s.lis.Accept()
		if err != nil {
			return
		}
		t, err := NewServerTransport("http2", conn, maxStreams, nil)
		if err != nil {
			return
		}
		s.mu.Lock()
		if s.conns == nil {
			s.mu.Unlock()
			t.Close()
			return
		}
		s.conns[t] = true
		s.mu.Unlock()
		h := &testStreamHandler{t}
		switch ht {
		case suspended:
			go t.HandleStreams(h.handleStreamSuspension)
		case misbehaved:
			go t.HandleStreams(h.handleStreamMisbehave)
		default:
			go t.HandleStreams(h.handleStream)
		}
	}
}

// printFeatures lists all the features within the given bounding Rectangle.
func printFeatures(client pb.RouteGuideClient, rect *pb.Rectangle) {
	grpclog.Printf("Looking for features within %v", rect)
	stream, err := client.ListFeatures(context.Background(), rect)
	if err != nil {
		grpclog.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
	}
	for {
		feature, err := stream.Recv()
		if err == io.EOF {
			break
		}
		if err != nil {
			grpclog.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
		}
		grpclog.Println(feature)
	}
}

// printFeature gets the feature for the given point.
func printFeature(client pb.RouteGuideClient, point *pb.Point) {
	grpclog.Printf("Getting feature for point (%d, %d)", point.Latitude, point.Longitude)
	feature, err := client.GetFeature(context.Background(), point)
	if err != nil {
		grpclog.Fatalf("%v.GetFeatures(_) = _, %v: ", client, err)
	}
	grpclog.Println(feature)
}

// RegisterService register a service and its implementation to the gRPC
// server. Called from the IDL generated code. This must be called before
// invoking Serve.
func (s *Server) RegisterService(sd *ServiceDesc, ss interface{}) {
	ht := reflect.TypeOf(sd.HandlerType).Elem()
	st := reflect.TypeOf(ss)
	if !st.Implements(ht) {
		grpclog.Fatalf("grpc: Server.RegisterService found the handler of type %v that does not satisfy %v", st, ht)
	}
	s.register(sd, ss)
}