Beispiel #1
0
// 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.ClientBefore(opentracing.ToHTTPRequest(tracer, 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.ClientBefore(opentracing.ToHTTPRequest(tracer, 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
}
Beispiel #2
0
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)
	}
}
Beispiel #3
0
// MakeConcatEndpointFactory generates a Factory that transforms an http url
// into an Endpoint.
//
// The path of the url is reset to /concat.
func MakeConcatEndpointFactory(tracer opentracing.Tracer, tracingLogger log.Logger) loadbalancer.Factory {
	return func(instance string) (endpoint.Endpoint, io.Closer, error) {
		concatURL, err := url.Parse(instance)
		if err != nil {
			return nil, nil, err
		}
		concatURL.Path = "/concat"

		client := httptransport.NewClient(
			"GET",
			concatURL,
			server.EncodeConcatRequest,
			server.DecodeConcatResponse,
			httptransport.SetClient(nil),
			httptransport.SetClientBefore(kitot.ToHTTPRequest(tracer, tracingLogger)),
		)

		return client.Endpoint(), nil, nil
	}
}