Example #1
0
// Endpoint is an example API endpoint. In a real application, the backend of
// your service would be contacting several external and internal API endpoints
// which may be the bottleneck of your application.
//
// For example purposes we just sleep for 200ms before responding to simulate a
// slow API endpoint as the bottleneck of your application.
func Endpoint(w http.ResponseWriter, r *http.Request) {
	// Extract the trace from the headers and join it with a new child span.
	carrier := opentracing.HTTPHeaderTextMapCarrier(r.Header)
	span, err := opentracing.GlobalTracer().Join(r.URL.Path, opentracing.TextMap, carrier)
	if err != nil {
		return
	}
	defer span.Finish()

	span.SetTag("Request.Host", r.Host)
	span.SetTag("Request.Method", r.Method)
	addHeaderTags(span, r.Header)

	time.Sleep(200 * time.Millisecond)
	fmt.Fprintf(w, "Slept for 200ms!")
}
Example #2
0
File: main.go Project: crezam/kit
func main() {
	var (
		httpAddr     = flag.String("http.addr", ":8000", "Address for HTTP (JSON) server")
		consulAddr   = flag.String("consul.addr", "", "Consul agent address")
		retryMax     = flag.Int("retry.max", 3, "per-request retries to different instances")
		retryTimeout = flag.Duration("retry.timeout", 500*time.Millisecond, "per-request timeout, including retries")
	)
	flag.Parse()

	// Logging domain.
	var logger log.Logger
	{
		logger = log.NewLogfmtLogger(os.Stderr)
		logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC)
		logger = log.NewContext(logger).With("caller", log.DefaultCaller)
	}

	// Service discovery domain. In this example we use Consul.
	var client consulsd.Client
	{
		consulConfig := api.DefaultConfig()
		if len(*consulAddr) > 0 {
			consulConfig.Address = *consulAddr
		}
		consulClient, err := api.NewClient(consulConfig)
		if err != nil {
			logger.Log("err", err)
			os.Exit(1)
		}
		client = consulsd.NewClient(consulClient)
	}

	// Transport domain.
	tracer := stdopentracing.GlobalTracer() // no-op
	ctx := context.Background()
	r := mux.NewRouter()

	// Now we begin installing the routes. Each route corresponds to a single
	// method: sum, concat, uppercase, and count.

	// addsvc routes.
	{
		// Each method gets constructed with a factory. Factories take an
		// instance string, and return a specific endpoint. In the factory we
		// dial the instance string we get from Consul, and then leverage an
		// addsvc client package to construct a complete service. We can then
		// leverage the addsvc.Make{Sum,Concat}Endpoint constructors to convert
		// the complete service to specific endpoint.

		var (
			tags        = []string{}
			passingOnly = true
			endpoints   = addsvc.Endpoints{}
		)
		{
			factory := addsvcFactory(addsvc.MakeSumEndpoint, tracer, logger)
			subscriber := consulsd.NewSubscriber(client, factory, logger, "addsvc", tags, passingOnly)
			balancer := lb.NewRoundRobin(subscriber)
			retry := lb.Retry(*retryMax, *retryTimeout, balancer)
			endpoints.SumEndpoint = retry
		}
		{
			factory := addsvcFactory(addsvc.MakeConcatEndpoint, tracer, logger)
			subscriber := consulsd.NewSubscriber(client, factory, logger, "addsvc", tags, passingOnly)
			balancer := lb.NewRoundRobin(subscriber)
			retry := lb.Retry(*retryMax, *retryTimeout, balancer)
			endpoints.ConcatEndpoint = retry
		}

		// Here we leverage the fact that addsvc comes with a constructor for an
		// HTTP handler, and just install it under a particular path prefix in
		// our router.

		r.PathPrefix("addsvc/").Handler(addsvc.MakeHTTPHandler(ctx, endpoints, tracer, logger))
	}

	// stringsvc routes.
	{
		// addsvc had lots of nice importable Go packages we could leverage.
		// With stringsvc we are not so fortunate, it just has some endpoints
		// that we assume will exist. So we have to write that logic here. This
		// is by design, so you can see two totally different methods of
		// proxying to a remote service.

		var (
			tags        = []string{}
			passingOnly = true
			uppercase   endpoint.Endpoint
			count       endpoint.Endpoint
		)
		{
			factory := stringsvcFactory(ctx, "GET", "/uppercase")
			subscriber := consulsd.NewSubscriber(client, factory, logger, "stringsvc", tags, passingOnly)
			balancer := lb.NewRoundRobin(subscriber)
			retry := lb.Retry(*retryMax, *retryTimeout, balancer)
			uppercase = retry
		}
		{
			factory := stringsvcFactory(ctx, "GET", "/count")
			subscriber := consulsd.NewSubscriber(client, factory, logger, "stringsvc", tags, passingOnly)
			balancer := lb.NewRoundRobin(subscriber)
			retry := lb.Retry(*retryMax, *retryTimeout, balancer)
			count = retry
		}

		// We can use the transport/http.Server to act as our handler, all we
		// have to do provide it with the encode and decode functions for our
		// stringsvc methods.

		r.Handle("/stringsvc/uppercase", httptransport.NewServer(ctx, uppercase, decodeUppercaseRequest, encodeJSONResponse))
		r.Handle("/stringsvc/count", httptransport.NewServer(ctx, count, decodeCountRequest, encodeJSONResponse))
	}

	// Interrupt handler.
	errc := make(chan error)
	go func() {
		c := make(chan os.Signal)
		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
		errc <- fmt.Errorf("%s", <-c)
	}()

	// HTTP transport.
	go func() {
		logger.Log("transport", "HTTP", "addr", *httpAddr)
		errc <- http.ListenAndServe(*httpAddr, r)
	}()

	// Run!
	logger.Log("exit", <-errc)
}
Example #3
0
File: main.go Project: patterns/re
func main() {
	var (
		debugAddr   = flag.String("debug.addr", ":8080", "Debug and metrics listen address")
		grpcAddr    = flag.String("grpc.addr", ":8082", "gRPC (HTTP) listen address")
		appdashAddr = flag.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		ircNick     = flag.String("irc.nick", "gogrpctest", "IRC nickname")
		ircSecret   = flag.String("irc.secret", "", "IRC password")
		ircHost     = flag.String("irc.addr", "irc.freenode.net:6667", "IRC host system")
	)
	flag.Parse()

	// Logging domain.
	var logger log.Logger
	{
		logger = log.NewLogfmtLogger(os.Stdout)
		logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC)
		logger = log.NewContext(logger).With("caller", log.DefaultCaller)
	}
	logger.Log("msg", "hello")
	defer logger.Log("msg", "goodbye")

	// Metrics domain.
	var cx, cxerr, joins metrics.Counter
	{
		// Business level metrics.
		cx = prometheus.NewCounterFrom(stdprometheus.CounterOpts{
			Namespace: "relay",
			Name:      "connect_succeeded",
			Help:      "Total count of connects via the Connect method.",
		}, []string{})
		cxerr = prometheus.NewCounterFrom(stdprometheus.CounterOpts{
			Namespace: "relay",
			Name:      "connect_failed",
			Help:      "Total count of connect errors via the Connect method.",
		}, []string{})
		joins = prometheus.NewCounterFrom(stdprometheus.CounterOpts{
			Namespace: "relay",
			Name:      "channels_joined",
			Help:      "Total count of channels joined via the Join method.",
		}, []string{})
	}
	var duration metrics.Histogram
	{
		// Transport level metrics.
		duration = prometheus.NewSummaryFrom(stdprometheus.SummaryOpts{
			Namespace: "relay",
			Name:      "request_duration_ns",
			Help:      "Request duration in nanoseconds.",
		}, []string{"method", "success"})
	}

	// Tracing domain.
	var tracer stdopentracing.Tracer
	{
		if *appdashAddr != "" {
			logger := log.NewContext(logger).With("tracer", "Appdash")
			logger.Log("addr", *appdashAddr)
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		} else {
			logger := log.NewContext(logger).With("tracer", "none")
			logger.Log()
			tracer = stdopentracing.GlobalTracer() // no-op
		}
	}

	// Business domain.
	var service relay.Service
	{
		service = relay.NewBasicService(*ircNick, *ircHost, *ircSecret)
		service = relay.ServiceLoggingMiddleware(logger)(service)
		service = relay.ServiceInstrumentingMiddleware(cx, cxerr, joins)(service)
	}

	// Endpoint domain.
	var connectEndpoint endpoint.Endpoint
	{
		connectDuration := duration.With("method", "Connect")
		connectLogger := log.NewContext(logger).With("method", "Connect")

		connectEndpoint = relay.MakeConnectEndpoint(service)
		connectEndpoint = opentracing.TraceServer(tracer, "Connect")(connectEndpoint)
		connectEndpoint = relay.EndpointInstrumentingMiddleware(connectDuration)(connectEndpoint)
		connectEndpoint = relay.EndpointLoggingMiddleware(connectLogger)(connectEndpoint)
	}
	var joinEndpoint endpoint.Endpoint
	{
		joinDuration := duration.With("method", "Join")
		joinLogger := log.NewContext(logger).With("method", "Join")

		joinEndpoint = relay.MakeJoinEndpoint(service)
		joinEndpoint = opentracing.TraceServer(tracer, "Join")(joinEndpoint)
		joinEndpoint = relay.EndpointInstrumentingMiddleware(joinDuration)(joinEndpoint)
		joinEndpoint = relay.EndpointLoggingMiddleware(joinLogger)(joinEndpoint)
	}
	endpoints := relay.Endpoints{
		ConnectEndpoint: connectEndpoint,
		JoinEndpoint:    joinEndpoint,
	}

	// Mechanical domain.
	errc := make(chan error)
	ctx := context.Background()

	// Interrupt handler.
	go func() {
		c := make(chan os.Signal, 1)
		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
		errc <- fmt.Errorf("%s", <-c)
	}()

	// Debug listener.
	go func() {
		logger := log.NewContext(logger).With("transport", "debug")

		m := http.NewServeMux()
		m.Handle("/debug/pprof/", http.HandlerFunc(pprof.Index))
		m.Handle("/debug/pprof/cmdline", http.HandlerFunc(pprof.Cmdline))
		m.Handle("/debug/pprof/profile", http.HandlerFunc(pprof.Profile))
		m.Handle("/debug/pprof/symbol", http.HandlerFunc(pprof.Symbol))
		m.Handle("/debug/pprof/trace", http.HandlerFunc(pprof.Trace))
		m.Handle("/metrics", stdprometheus.Handler())

		logger.Log("addr", *debugAddr)
		errc <- http.ListenAndServe(*debugAddr, m)
	}()

	// gRPC transport.
	go func() {
		logger := log.NewContext(logger).With("transport", "gRPC")

		ln, err := net.Listen("tcp", *grpcAddr)
		if err != nil {
			errc <- err
			return
		}

		srv := relay.MakeGRPCServer(ctx, endpoints, tracer, logger)
		s := grpc.NewServer()
		pb.RegisterRelayServer(s, srv)

		logger.Log("addr", *grpcAddr)
		errc <- s.Serve(ln)
	}()

	// Run!
	logger.Log("exit", <-errc)
}
Example #4
0
File: main.go Project: patterns/re
func main() {
	// The relaycli presumes no service discovery system, and expects users to
	// provide the direct address of a relaysvc. This presumption is reflected in
	// the relaycli binary and the the client packages: the -transport.addr flags
	// and various client constructors both expect host:port strings.

	var (
		grpcAddr    = flag.String("grpc.addr", "", "gRPC (HTTP) address of relaysvc")
		appdashAddr = flag.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		method      = flag.String("method", "connect", "connect, join")
	)
	flag.Parse()

	if len(flag.Args()) != 1 {
		fmt.Fprintf(os.Stderr, "usage: relaycli [flags] <s>\n")
		os.Exit(1)
	}

	var tracer stdopentracing.Tracer
	{
		if *appdashAddr != "" {
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		} else {
			tracer = stdopentracing.GlobalTracer() // no-op
		}
	}

	var (
		service relay.Service
		err     error
	)
	if *grpcAddr != "" {
		conn, err := grpc.Dial(*grpcAddr, grpc.WithInsecure(), grpc.WithTimeout(time.Second))
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v", err)
			os.Exit(1)
		}
		defer conn.Close()
		service = grpcclient.New(conn, tracer, log.NewNopLogger())
	} else {
		fmt.Fprintf(os.Stderr, "error: no remote address specified\n")
		os.Exit(1)
	}
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	switch *method {
	case "connect":
		s := flag.Args()[0]
		v, err := service.Connect(context.Background(), s)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stdout, "Connect to %s: %s\n", s, v)

	case "join":
		c := flag.Args()[0]
		v, err := service.Join(context.Background(), c)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stdout, "Join channel %s: %s\n", c, v)

	default:
		fmt.Fprintf(os.Stderr, "error: invalid method %q\n", method)
		os.Exit(1)
	}
}
Example #5
0
File: main.go Project: crezam/kit
func main() {
	var (
		debugAddr        = flag.String("debug.addr", ":8080", "Debug and metrics listen address")
		httpAddr         = flag.String("http.addr", ":8081", "HTTP listen address")
		grpcAddr         = flag.String("grpc.addr", ":8082", "gRPC (HTTP) listen address")
		thriftAddr       = flag.String("thrift.addr", ":8083", "Thrift listen address")
		thriftProtocol   = flag.String("thrift.protocol", "binary", "binary, compact, json, simplejson")
		thriftBufferSize = flag.Int("thrift.buffer.size", 0, "0 for unbuffered")
		thriftFramed     = flag.Bool("thrift.framed", false, "true to enable framing")
		zipkinAddr       = flag.String("zipkin.addr", "", "Enable Zipkin tracing via a Kafka server host:port")
		appdashAddr      = flag.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		lightstepToken   = flag.String("lightstep.token", "", "Enable LightStep tracing via a LightStep access token")
	)
	flag.Parse()

	// Logging domain.
	var logger log.Logger
	{
		logger = log.NewLogfmtLogger(os.Stdout)
		logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC)
		logger = log.NewContext(logger).With("caller", log.DefaultCaller)
	}
	logger.Log("msg", "hello")
	defer logger.Log("msg", "goodbye")

	// Metrics domain.
	var ints, chars metrics.Counter
	{
		// Business level metrics.
		ints = prometheus.NewCounter(stdprometheus.CounterOpts{
			Namespace: "addsvc",
			Name:      "integers_summed",
			Help:      "Total count of integers summed via the Sum method.",
		}, []string{})
		chars = prometheus.NewCounter(stdprometheus.CounterOpts{
			Namespace: "addsvc",
			Name:      "characters_concatenated",
			Help:      "Total count of characters concatenated via the Concat method.",
		}, []string{})
	}
	var duration metrics.TimeHistogram
	{
		// Transport level metrics.
		duration = metrics.NewTimeHistogram(time.Nanosecond, prometheus.NewSummary(stdprometheus.SummaryOpts{
			Namespace: "addsvc",
			Name:      "request_duration_ns",
			Help:      "Request duration in nanoseconds.",
		}, []string{"method", "success"}))
	}

	// Tracing domain.
	var tracer stdopentracing.Tracer
	{
		if *zipkinAddr != "" {
			logger := log.NewContext(logger).With("tracer", "Zipkin")
			logger.Log("addr", *zipkinAddr)
			collector, err := zipkin.NewKafkaCollector(
				strings.Split(*zipkinAddr, ","),
				zipkin.KafkaLogger(logger),
			)
			if err != nil {
				logger.Log("err", err)
				os.Exit(1)
			}
			tracer, err = zipkin.NewTracer(
				zipkin.NewRecorder(collector, false, "localhost:80", "addsvc"),
			)
			if err != nil {
				logger.Log("err", err)
				os.Exit(1)
			}
		} else if *appdashAddr != "" {
			logger := log.NewContext(logger).With("tracer", "Appdash")
			logger.Log("addr", *appdashAddr)
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		} else if *lightstepToken != "" {
			logger := log.NewContext(logger).With("tracer", "LightStep")
			logger.Log() // probably don't want to print out the token :)
			tracer = lightstep.NewTracer(lightstep.Options{
				AccessToken: *lightstepToken,
			})
			defer lightstep.FlushLightStepTracer(tracer)
		} else {
			logger := log.NewContext(logger).With("tracer", "none")
			logger.Log()
			tracer = stdopentracing.GlobalTracer() // no-op
		}
	}

	// Business domain.
	var service addsvc.Service
	{
		service = addsvc.NewBasicService()
		service = addsvc.ServiceLoggingMiddleware(logger)(service)
		service = addsvc.ServiceInstrumentingMiddleware(ints, chars)(service)
	}

	// Endpoint domain.
	var sumEndpoint endpoint.Endpoint
	{
		sumDuration := duration.With(metrics.Field{Key: "method", Value: "Sum"})
		sumLogger := log.NewContext(logger).With("method", "Sum")

		sumEndpoint = addsvc.MakeSumEndpoint(service)
		sumEndpoint = opentracing.TraceServer(tracer, "Sum")(sumEndpoint)
		sumEndpoint = addsvc.EndpointInstrumentingMiddleware(sumDuration)(sumEndpoint)
		sumEndpoint = addsvc.EndpointLoggingMiddleware(sumLogger)(sumEndpoint)
	}
	var concatEndpoint endpoint.Endpoint
	{
		concatDuration := duration.With(metrics.Field{Key: "method", Value: "Concat"})
		concatLogger := log.NewContext(logger).With("method", "Concat")

		concatEndpoint = addsvc.MakeConcatEndpoint(service)
		concatEndpoint = opentracing.TraceServer(tracer, "Concat")(concatEndpoint)
		concatEndpoint = addsvc.EndpointInstrumentingMiddleware(concatDuration)(concatEndpoint)
		concatEndpoint = addsvc.EndpointLoggingMiddleware(concatLogger)(concatEndpoint)
	}
	endpoints := addsvc.Endpoints{
		SumEndpoint:    sumEndpoint,
		ConcatEndpoint: concatEndpoint,
	}

	// Mechanical domain.
	errc := make(chan error)
	ctx := context.Background()

	// Interrupt handler.
	go func() {
		c := make(chan os.Signal, 1)
		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
		errc <- fmt.Errorf("%s", <-c)
	}()

	// Debug listener.
	go func() {
		logger := log.NewContext(logger).With("transport", "debug")

		m := http.NewServeMux()
		m.Handle("/debug/pprof/", http.HandlerFunc(pprof.Index))
		m.Handle("/debug/pprof/cmdline", http.HandlerFunc(pprof.Cmdline))
		m.Handle("/debug/pprof/profile", http.HandlerFunc(pprof.Profile))
		m.Handle("/debug/pprof/symbol", http.HandlerFunc(pprof.Symbol))
		m.Handle("/debug/pprof/trace", http.HandlerFunc(pprof.Trace))
		m.Handle("/metrics", stdprometheus.Handler())

		logger.Log("addr", *debugAddr)
		errc <- http.ListenAndServe(*debugAddr, m)
	}()

	// HTTP transport.
	go func() {
		logger := log.NewContext(logger).With("transport", "HTTP")
		h := addsvc.MakeHTTPHandler(ctx, endpoints, tracer, logger)
		logger.Log("addr", *httpAddr)
		errc <- http.ListenAndServe(*httpAddr, h)
	}()

	// gRPC transport.
	go func() {
		logger := log.NewContext(logger).With("transport", "gRPC")

		ln, err := net.Listen("tcp", *grpcAddr)
		if err != nil {
			errc <- err
			return
		}

		srv := addsvc.MakeGRPCServer(ctx, endpoints, tracer, logger)
		s := grpc.NewServer()
		pb.RegisterAddServer(s, srv)

		logger.Log("addr", *grpcAddr)
		errc <- s.Serve(ln)
	}()

	// Thrift transport.
	go func() {
		logger := log.NewContext(logger).With("transport", "Thrift")

		var protocolFactory thrift.TProtocolFactory
		switch *thriftProtocol {
		case "binary":
			protocolFactory = thrift.NewTBinaryProtocolFactoryDefault()
		case "compact":
			protocolFactory = thrift.NewTCompactProtocolFactory()
		case "json":
			protocolFactory = thrift.NewTJSONProtocolFactory()
		case "simplejson":
			protocolFactory = thrift.NewTSimpleJSONProtocolFactory()
		default:
			errc <- fmt.Errorf("invalid Thrift protocol %q", *thriftProtocol)
			return
		}

		var transportFactory thrift.TTransportFactory
		if *thriftBufferSize > 0 {
			transportFactory = thrift.NewTBufferedTransportFactory(*thriftBufferSize)
		} else {
			transportFactory = thrift.NewTTransportFactory()
		}
		if *thriftFramed {
			transportFactory = thrift.NewTFramedTransportFactory(transportFactory)
		}

		transport, err := thrift.NewTServerSocket(*thriftAddr)
		if err != nil {
			errc <- err
			return
		}

		logger.Log("addr", *thriftAddr)
		errc <- thrift.NewTSimpleServer4(
			thriftadd.NewAddServiceProcessor(addsvc.MakeThriftHandler(ctx, endpoints)),
			transport,
			transportFactory,
			protocolFactory,
		).Serve()
	}()

	// Run!
	logger.Log("exit", <-errc)
}
Example #6
0
File: main.go Project: crezam/kit
func main() {
	// The addcli presumes no service discovery system, and expects users to
	// provide the direct address of an addsvc. This presumption is reflected in
	// the addcli binary and the the client packages: the -transport.addr flags
	// and various client constructors both expect host:port strings. For an
	// example service with a client built on top of a service discovery system,
	// see profilesvc.

	var (
		httpAddr         = flag.String("http.addr", "", "HTTP address of addsvc")
		grpcAddr         = flag.String("grpc.addr", "", "gRPC (HTTP) address of addsvc")
		thriftAddr       = flag.String("thrift.addr", "", "Thrift address of addsvc")
		thriftProtocol   = flag.String("thrift.protocol", "binary", "binary, compact, json, simplejson")
		thriftBufferSize = flag.Int("thrift.buffer.size", 0, "0 for unbuffered")
		thriftFramed     = flag.Bool("thrift.framed", false, "true to enable framing")
		zipkinAddr       = flag.String("zipkin.addr", "", "Enable Zipkin tracing via a Kafka Collector host:port")
		appdashAddr      = flag.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		lightstepToken   = flag.String("lightstep.token", "", "Enable LightStep tracing via a LightStep access token")
		method           = flag.String("method", "sum", "sum, concat")
	)
	flag.Parse()

	if len(flag.Args()) != 2 {
		fmt.Fprintf(os.Stderr, "usage: addcli [flags] <a> <b>\n")
		os.Exit(1)
	}

	// This is a demonstration client, which supports multiple tracers.
	// Your clients will probably just use one tracer.
	var tracer stdopentracing.Tracer
	{
		if *zipkinAddr != "" {
			collector, err := zipkin.NewKafkaCollector(
				strings.Split(*zipkinAddr, ","),
				zipkin.KafkaLogger(log.NewNopLogger()),
			)
			if err != nil {
				fmt.Fprintf(os.Stderr, "%v\n", err)
				os.Exit(1)
			}
			tracer, err = zipkin.NewTracer(
				zipkin.NewRecorder(collector, false, "localhost:8000", "addcli"),
			)
			if err != nil {
				fmt.Fprintf(os.Stderr, "%v\n", err)
				os.Exit(1)
			}
		} else if *appdashAddr != "" {
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		} else if *lightstepToken != "" {
			tracer = lightstep.NewTracer(lightstep.Options{
				AccessToken: *lightstepToken,
			})
			defer lightstep.FlushLightStepTracer(tracer)
		} else {
			tracer = stdopentracing.GlobalTracer() // no-op
		}
	}

	// This is a demonstration client, which supports multiple transports.
	// Your clients will probably just define and stick with 1 transport.

	var (
		service addsvc.Service
		err     error
	)
	if *httpAddr != "" {
		service, err = httpclient.New(*httpAddr, tracer, log.NewNopLogger())
	} else if *grpcAddr != "" {
		conn, err := grpc.Dial(*grpcAddr, grpc.WithInsecure(), grpc.WithTimeout(time.Second))
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v", err)
			os.Exit(1)
		}
		defer conn.Close()
		service = grpcclient.New(conn, tracer, log.NewNopLogger())
	} else if *thriftAddr != "" {
		// It's necessary to do all of this construction in the func main,
		// because (among other reasons) we need to control the lifecycle of the
		// Thrift transport, i.e. close it eventually.
		var protocolFactory thrift.TProtocolFactory
		switch *thriftProtocol {
		case "compact":
			protocolFactory = thrift.NewTCompactProtocolFactory()
		case "simplejson":
			protocolFactory = thrift.NewTSimpleJSONProtocolFactory()
		case "json":
			protocolFactory = thrift.NewTJSONProtocolFactory()
		case "binary", "":
			protocolFactory = thrift.NewTBinaryProtocolFactoryDefault()
		default:
			fmt.Fprintf(os.Stderr, "error: invalid protocol %q\n", *thriftProtocol)
			os.Exit(1)
		}
		var transportFactory thrift.TTransportFactory
		if *thriftBufferSize > 0 {
			transportFactory = thrift.NewTBufferedTransportFactory(*thriftBufferSize)
		} else {
			transportFactory = thrift.NewTTransportFactory()
		}
		if *thriftFramed {
			transportFactory = thrift.NewTFramedTransportFactory(transportFactory)
		}
		transportSocket, err := thrift.NewTSocket(*thriftAddr)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		transport := transportFactory.GetTransport(transportSocket)
		if err := transport.Open(); err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		defer transport.Close()
		client := thriftadd.NewAddServiceClientFactory(transport, protocolFactory)
		service = thriftclient.New(client)
	} else {
		fmt.Fprintf(os.Stderr, "error: no remote address specified\n")
		os.Exit(1)
	}
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	switch *method {
	case "sum":
		a, _ := strconv.ParseInt(flag.Args()[0], 10, 64)
		b, _ := strconv.ParseInt(flag.Args()[1], 10, 64)
		v, err := service.Sum(context.Background(), int(a), int(b))
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stdout, "%d + %d = %d\n", a, b, v)

	case "concat":
		a := flag.Args()[0]
		b := flag.Args()[1]
		v, err := service.Concat(context.Background(), a, b)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stdout, "%q + %q = %q\n", a, b, v)

	default:
		fmt.Fprintf(os.Stderr, "error: invalid method %q\n", method)
		os.Exit(1)
	}
}