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)
}
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)
}