// New returns an AddService backed by an HTTP server living at the remote
// instance. We expect instance to come from a service discovery system, so
// likely of the form "host:port".
func New(instance string, tracer stdopentracing.Tracer, logger log.Logger) (addsvc.Service, error) {
if !strings.HasPrefix(instance, "http") {
instance = "http://" + instance
}
u, err := url.Parse(instance)
if err != nil {
return nil, err
}
// We construct a single ratelimiter middleware, to limit the total outgoing
// QPS from this client to all methods on the remote instance. We also
// construct per-endpoint circuitbreaker middlewares to demonstrate how
// that's done, although they could easily be combined into a single breaker
// for the entire remote instance, too.
limiter := ratelimit.NewTokenBucketLimiter(jujuratelimit.NewBucketWithRate(100, 100))
var sumEndpoint endpoint.Endpoint
{
sumEndpoint = httptransport.NewClient(
"POST",
copyURL(u, "/sum"),
addsvc.EncodeHTTPGenericRequest,
addsvc.DecodeHTTPSumResponse,
httptransport.SetClientBefore(opentracing.FromHTTPRequest(tracer, "Sum", logger)),
).Endpoint()
sumEndpoint = opentracing.TraceClient(tracer, "Sum")(sumEndpoint)
sumEndpoint = limiter(sumEndpoint)
sumEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Sum",
Timeout: 30 * time.Second,
}))(sumEndpoint)
}
var concatEndpoint endpoint.Endpoint
{
concatEndpoint = httptransport.NewClient(
"POST",
copyURL(u, "/concat"),
addsvc.EncodeHTTPGenericRequest,
addsvc.DecodeHTTPConcatResponse,
httptransport.SetClientBefore(opentracing.FromHTTPRequest(tracer, "Concat", logger)),
).Endpoint()
concatEndpoint = opentracing.TraceClient(tracer, "Concat")(concatEndpoint)
concatEndpoint = limiter(concatEndpoint)
sumEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Concat",
Timeout: 30 * time.Second,
}))(sumEndpoint)
}
return addsvc.Endpoints{
SumEndpoint: sumEndpoint,
ConcatEndpoint: concatEndpoint,
}, nil
}
// MakeHTTPHandler returns a handler that makes a set of endpoints available
// on predefined paths.
func MakeHTTPHandler(ctx context.Context, endpoints Endpoints, tracer stdopentracing.Tracer, logger log.Logger) http.Handler {
options := []httptransport.ServerOption{
httptransport.ServerErrorEncoder(errorEncoder),
httptransport.ServerErrorLogger(logger),
}
m := http.NewServeMux()
m.Handle("/sum", httptransport.NewServer(
ctx,
endpoints.SumEndpoint,
DecodeHTTPSumRequest,
EncodeHTTPGenericResponse,
append(options, httptransport.ServerBefore(opentracing.FromHTTPRequest(tracer, "Sum", logger)))...,
))
m.Handle("/concat", httptransport.NewServer(
ctx,
endpoints.ConcatEndpoint,
DecodeHTTPConcatRequest,
EncodeHTTPGenericResponse,
append(options, httptransport.ServerBefore(opentracing.FromHTTPRequest(tracer, "Concat", logger)))...,
))
return m
}
func TestTraceHTTPRequestRoundtrip(t *testing.T) {
logger := log.NewNopLogger()
tracer := mocktracer.New()
// Initialize the ctx with a Span to inject.
beforeSpan := tracer.StartSpan("to_inject").(*mocktracer.MockSpan)
defer beforeSpan.Finish()
beforeSpan.SetBaggageItem("baggage", "check")
beforeCtx := opentracing.ContextWithSpan(context.Background(), beforeSpan)
toHTTPFunc := kitot.ToHTTPRequest(tracer, logger)
req, _ := http.NewRequest("GET", "http://test.biz/url", nil)
// Call the RequestFunc.
afterCtx := toHTTPFunc(beforeCtx, req)
// The Span should not have changed.
afterSpan := opentracing.SpanFromContext(afterCtx)
if beforeSpan != afterSpan {
t.Errorf("Should not swap in a new span")
}
// No spans should have finished yet.
finishedSpans := tracer.FinishedSpans()
if want, have := 0, len(finishedSpans); want != have {
t.Errorf("Want %v span(s), found %v", want, have)
}
// Use FromHTTPRequest to verify that we can join with the trace given a req.
fromHTTPFunc := kitot.FromHTTPRequest(tracer, "joined", logger)
joinCtx := fromHTTPFunc(afterCtx, req)
joinedSpan := opentracing.SpanFromContext(joinCtx).(*mocktracer.MockSpan)
joinedContext := joinedSpan.Context().(mocktracer.MockSpanContext)
beforeContext := beforeSpan.Context().(mocktracer.MockSpanContext)
if joinedContext.SpanID == beforeContext.SpanID {
t.Error("SpanID should have changed", joinedContext.SpanID, beforeContext.SpanID)
}
// Check that the parent/child relationship is as expected for the joined span.
if want, have := beforeContext.SpanID, joinedSpan.ParentID; want != have {
t.Errorf("Want ParentID %q, have %q", want, have)
}
if want, have := "joined", joinedSpan.OperationName; want != have {
t.Errorf("Want %q, have %q", want, have)
}
if want, have := "check", joinedSpan.BaggageItem("baggage"); want != have {
t.Errorf("Want %q, have %q", want, have)
}
}
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)
}