Exemple #1
0
func main() {
	// Flag domain. Note that gRPC transitively registers flags via its import
	// of glog. So, we define a new flag set, to keep those domains distinct.
	fs := flag.NewFlagSet("", flag.ExitOnError)
	var (
		debugAddr        = fs.String("debug.addr", ":8000", "Address for HTTP debug/instrumentation server")
		httpAddr         = fs.String("http.addr", ":8001", "Address for HTTP (JSON) server")
		grpcAddr         = fs.String("grpc.addr", ":8002", "Address for gRPC server")
		netrpcAddr       = fs.String("netrpc.addr", ":8003", "Address for net/rpc server")
		thriftAddr       = fs.String("thrift.addr", ":8004", "Address for Thrift server")
		thriftProtocol   = fs.String("thrift.protocol", "binary", "binary, compact, json, simplejson")
		thriftBufferSize = fs.Int("thrift.buffer.size", 0, "0 for unbuffered")
		thriftFramed     = fs.Bool("thrift.framed", false, "true to enable framing")

		// Supported OpenTracing backends
		zipkinAddr           = fs.String("zipkin.kafka.addr", "", "Enable Zipkin tracing via a Kafka server host:port")
		appdashAddr          = fs.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		lightstepAccessToken = fs.String("lightstep.token", "", "Enable LightStep tracing via a LightStep access token")
	)
	flag.Usage = fs.Usage // only show our flags
	if err := fs.Parse(os.Args[1:]); err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}

	// package log
	var logger log.Logger
	{
		logger = log.NewLogfmtLogger(os.Stderr)
		logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC).With("caller", log.DefaultCaller)
		stdlog.SetFlags(0)                             // flags are handled by Go kit's logger
		stdlog.SetOutput(log.NewStdlibAdapter(logger)) // redirect anything using stdlib log to us
	}

	// package metrics
	var requestDuration metrics.TimeHistogram
	{
		requestDuration = metrics.NewTimeHistogram(time.Nanosecond, metrics.NewMultiHistogram(
			"request_duration_ns",
			expvar.NewHistogram("request_duration_ns", 0, 5e9, 1, 50, 95, 99),
			prometheus.NewSummary(stdprometheus.SummaryOpts{
				Namespace: "myorg",
				Subsystem: "addsvc",
				Name:      "duration_ns",
				Help:      "Request duration in nanoseconds.",
			}, []string{"method"}),
		))
	}

	// Set up OpenTracing
	var tracer opentracing.Tracer
	{
		switch {
		case *appdashAddr != "" && *lightstepAccessToken == "" && *zipkinAddr == "":
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		case *appdashAddr == "" && *lightstepAccessToken != "" && *zipkinAddr == "":
			tracer = lightstep.NewTracer(lightstep.Options{
				AccessToken: *lightstepAccessToken,
			})
			defer lightstep.FlushLightStepTracer(tracer)
		case *appdashAddr == "" && *lightstepAccessToken == "" && *zipkinAddr != "":
			collector, err := zipkin.NewKafkaCollector(
				strings.Split(*zipkinAddr, ","),
				zipkin.KafkaLogger(logger),
			)
			if err != nil {
				logger.Log("err", "unable to create collector", "fatal", err)
				os.Exit(1)
			}
			tracer, err = zipkin.NewTracer(
				zipkin.NewRecorder(collector, false, "localhost:80", "addsvc"),
			)
			if err != nil {
				logger.Log("err", "unable to create zipkin tracer", "fatal", err)
				os.Exit(1)
			}
		case *appdashAddr == "" && *lightstepAccessToken == "" && *zipkinAddr == "":
			tracer = opentracing.GlobalTracer() // no-op
		default:
			logger.Log("fatal", "specify a single -appdash.addr, -lightstep.access.token or -zipkin.kafka.addr")
			os.Exit(1)
		}
	}

	// Business domain
	var svc server.AddService
	{
		svc = pureAddService{}
		svc = loggingMiddleware{svc, logger}
		svc = instrumentingMiddleware{svc, requestDuration}
	}

	// Mechanical stuff
	rand.Seed(time.Now().UnixNano())
	root := context.Background()
	errc := make(chan error)

	go func() {
		errc <- interrupt()
	}()

	// Debug/instrumentation
	go func() {
		transportLogger := log.NewContext(logger).With("transport", "debug")
		transportLogger.Log("addr", *debugAddr)
		errc <- http.ListenAndServe(*debugAddr, nil) // DefaultServeMux
	}()

	// Transport: HTTP/JSON
	go func() {
		var (
			transportLogger = log.NewContext(logger).With("transport", "HTTP/JSON")
			tracingLogger   = log.NewContext(transportLogger).With("component", "tracing")
			mux             = http.NewServeMux()
			sum, concat     endpoint.Endpoint
		)

		sum = makeSumEndpoint(svc)
		sum = kitot.TraceServer(tracer, "sum")(sum)
		mux.Handle("/sum", httptransport.NewServer(
			root,
			sum,
			server.DecodeSumRequest,
			server.EncodeSumResponse,
			httptransport.ServerErrorLogger(transportLogger),
			httptransport.ServerBefore(kitot.FromHTTPRequest(tracer, "sum", tracingLogger)),
		))

		concat = makeConcatEndpoint(svc)
		concat = kitot.TraceServer(tracer, "concat")(concat)
		mux.Handle("/concat", httptransport.NewServer(
			root,
			concat,
			server.DecodeConcatRequest,
			server.EncodeConcatResponse,
			httptransport.ServerErrorLogger(transportLogger),
			httptransport.ServerBefore(kitot.FromHTTPRequest(tracer, "concat", tracingLogger)),
		))

		transportLogger.Log("addr", *httpAddr)
		errc <- http.ListenAndServe(*httpAddr, mux)
	}()

	// Transport: gRPC
	go func() {
		transportLogger := log.NewContext(logger).With("transport", "gRPC")
		tracingLogger := log.NewContext(transportLogger).With("component", "tracing")
		ln, err := net.Listen("tcp", *grpcAddr)
		if err != nil {
			errc <- err
			return
		}
		s := grpc.NewServer() // uses its own, internal context
		pb.RegisterAddServer(s, newGRPCBinding(root, tracer, svc, tracingLogger))
		transportLogger.Log("addr", *grpcAddr)
		errc <- s.Serve(ln)
	}()

	// Transport: net/rpc
	go func() {
		transportLogger := log.NewContext(logger).With("transport", "net/rpc")
		s := rpc.NewServer()
		if err := s.RegisterName("addsvc", netrpcBinding{svc}); err != nil {
			errc <- err
			return
		}
		s.HandleHTTP(rpc.DefaultRPCPath, rpc.DefaultDebugPath)
		transportLogger.Log("addr", *netrpcAddr)
		errc <- http.ListenAndServe(*netrpcAddr, s)
	}()

	// Transport: Thrift
	go func() {
		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
		}
		transportLogger := log.NewContext(logger).With("transport", "thrift")
		transportLogger.Log("addr", *thriftAddr)
		errc <- thrift.NewTSimpleServer4(
			thriftadd.NewAddServiceProcessor(thriftBinding{svc}),
			transport,
			transportFactory,
			protocolFactory,
		).Serve()
	}()

	logger.Log("fatal", <-errc)
}
Exemple #2
0
func main() {
	var (
		transport        = flag.String("transport", "httpjson", "httpjson, grpc, netrpc, thrift")
		httpAddrs        = flag.String("http.addrs", "localhost:8001", "Comma-separated list of addresses for HTTP (JSON) servers")
		grpcAddrs        = flag.String("grpc.addrs", "localhost:8002", "Comma-separated list of addresses for gRPC servers")
		netrpcAddrs      = flag.String("netrpc.addrs", "localhost:8003", "Comma-separated list of addresses for net/rpc servers")
		thriftAddrs      = flag.String("thrift.addrs", "localhost:8004", "Comma-separated list of addresses for Thrift servers")
		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")

		// Three OpenTracing backends (to demonstrate how they can be interchanged):
		zipkinAddr           = flag.String("zipkin.kafka.addr", "", "Enable Zipkin tracing via a Kafka Collector host:port")
		appdashAddr          = flag.String("appdash.addr", "", "Enable Appdash tracing via an Appdash server host:port")
		lightstepAccessToken = flag.String("lightstep.token", "", "Enable LightStep tracing via a LightStep access token")
	)
	flag.Parse()
	if len(os.Args) < 4 {
		fmt.Fprintf(os.Stderr, "\n%s [flags] method arg1 arg2\n\n", filepath.Base(os.Args[0]))
		flag.Usage()
		os.Exit(1)
	}

	randomSeed := time.Now().UnixNano()

	root := context.Background()
	method, s1, s2 := flag.Arg(0), flag.Arg(1), flag.Arg(2)

	var logger log.Logger
	logger = log.NewLogfmtLogger(os.Stdout)
	logger = log.NewContext(logger).With("caller", log.DefaultCaller)
	logger = log.NewContext(logger).With("transport", *transport)
	tracingLogger := log.NewContext(logger).With("component", "tracing")

	// Set up OpenTracing
	var tracer opentracing.Tracer
	{
		switch {
		case *appdashAddr != "" && *lightstepAccessToken == "" && *zipkinAddr == "":
			tracer = appdashot.NewTracer(appdash.NewRemoteCollector(*appdashAddr))
		case *appdashAddr == "" && *lightstepAccessToken != "" && *zipkinAddr == "":
			tracer = lightstep.NewTracer(lightstep.Options{
				AccessToken: *lightstepAccessToken,
			})
			defer lightstep.FlushLightStepTracer(tracer)
		case *appdashAddr == "" && *lightstepAccessToken == "" && *zipkinAddr != "":
			collector, err := zipkin.NewKafkaCollector(
				strings.Split(*zipkinAddr, ","),
				zipkin.KafkaLogger(tracingLogger),
			)
			if err != nil {
				tracingLogger.Log("err", "unable to create kafka collector", "fatal", err)
				os.Exit(1)
			}
			tracer, err = zipkin.NewTracer(
				zipkin.NewRecorder(collector, false, "localhost:8000", "addsvc-client"),
			)
			if err != nil {
				tracingLogger.Log("err", "unable to create zipkin tracer", "fatal", err)
				os.Exit(1)
			}
		case *appdashAddr == "" && *lightstepAccessToken == "" && *zipkinAddr == "":
			tracer = opentracing.GlobalTracer() // no-op
		default:
			tracingLogger.Log("fatal", "specify a single -appdash.addr, -lightstep.access.token or -zipkin.kafka.addr")
			os.Exit(1)
		}
	}

	var (
		instances                 []string
		sumFactory, concatFactory loadbalancer.Factory
	)

	switch *transport {
	case "grpc":
		instances = strings.Split(*grpcAddrs, ",")
		sumFactory = grpcclient.MakeSumEndpointFactory(tracer, tracingLogger)
		concatFactory = grpcclient.MakeConcatEndpointFactory(tracer, tracingLogger)

	case "httpjson":
		instances = strings.Split(*httpAddrs, ",")
		for i, rawurl := range instances {
			if !strings.HasPrefix("http", rawurl) {
				instances[i] = "http://" + rawurl
			}
		}
		sumFactory = httpjsonclient.MakeSumEndpointFactory(tracer, tracingLogger)
		concatFactory = httpjsonclient.MakeConcatEndpointFactory(tracer, tracingLogger)

	case "netrpc":
		instances = strings.Split(*netrpcAddrs, ",")
		sumFactory = netrpcclient.SumEndpointFactory
		concatFactory = netrpcclient.ConcatEndpointFactory

	case "thrift":
		instances = strings.Split(*thriftAddrs, ",")
		thriftClient := thriftclient.New(*thriftProtocol, *thriftBufferSize, *thriftFramed, logger)
		sumFactory = thriftClient.SumEndpoint
		concatFactory = thriftClient.ConcatEndpoint

	default:
		logger.Log("err", "invalid transport")
		os.Exit(1)
	}

	sum := buildEndpoint(tracer, "sum", instances, sumFactory, randomSeed, logger)
	concat := buildEndpoint(tracer, "concat", instances, concatFactory, randomSeed, logger)

	svc := newClient(root, sum, concat, logger)

	begin := time.Now()
	switch method {
	case "sum":
		a, _ := strconv.Atoi(s1)
		b, _ := strconv.Atoi(s2)
		v := svc.Sum(a, b)
		logger.Log("method", "sum", "a", a, "b", b, "v", v, "took", time.Since(begin))

	case "concat":
		a, b := s1, s2
		v := svc.Concat(a, b)
		logger.Log("method", "concat", "a", a, "b", b, "v", v, "took", time.Since(begin))

	default:
		logger.Log("err", "invalid method "+method)
		os.Exit(1)
	}
	// wait for collector
	time.Sleep(2 * time.Second)
}
Exemple #3
0
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)
}
Exemple #4
0
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)
	}
}