Add more tags to the admissionControl span to increase visibility

Updates #3317

Signed-off-by: Roman Zavodskikh <[email protected]>

filters/shedder/admission.go

@@ -370,6 +370,13 @@ func sum(a []int64) int64 {
 	return result
 }
 
+func (ac *admissionControl) setCommonTags(span opentracing.Span) {
+	span.SetTag("admissionControl.group", ac.metricSuffix)
+	span.SetTag("admissionControl.mode", ac.mode.String())
+	span.SetTag("admissionControl.d", ac.d.String())
+	span.SetTag("admissionControl.windowSize", ac.windowSize)
+}
+
 // calculates P_{reject} see https://opensource.zalando.com/skipper/reference/filters/#admissioncontrol
 func (ac *admissionControl) pReject() float64 {
 	var rejectP float64
@@ -412,6 +419,8 @@ func (ac *admissionControl) shouldReject() bool {
 func (ac *admissionControl) Request(ctx filters.FilterContext) {
 	span := ac.startSpan(ctx.Request().Context())
 	defer span.Finish()
+
+	ac.setCommonTags(span)
 	ac.metrics.IncCounter(counterPrefix + "total." + ac.metricSuffix)
 
 	if ac.shouldReject() {

filters/shedder/admission_test.go

@@ -13,15 +13,18 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/zalando/skipper/eskip"
 	"github.com/zalando/skipper/filters"
 	"github.com/zalando/skipper/filters/builtin"
 	"github.com/zalando/skipper/metrics"
 	"github.com/zalando/skipper/metrics/metricstest"
 	"github.com/zalando/skipper/net"
+	"github.com/zalando/skipper/proxy"
 	"github.com/zalando/skipper/proxy/proxytest"
 	"github.com/zalando/skipper/routing"
 	"github.com/zalando/skipper/routing/testdataclient"
+	"github.com/zalando/skipper/tracing/tracingtest"
 	"golang.org/x/time/rate"
 )
 
@@ -594,6 +597,95 @@ func TestAdmissionControlCleanupMultipleFilters(t *testing.T) {
 	}
 }
 
+func TestAdmissionControlSetsSpansTags(t *testing.T) {
+	tracer := tracingtest.NewMockTracer()
+
+	backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer backend.Close()
+
+	fspec := NewAdmissionControl(Options{Tracer: tracer})
+	spec, ok := fspec.(*AdmissionControlSpec)
+	if !ok {
+		t.Fatal("FilterSpec is not a AdmissionControlSpec")
+	}
+	preProcessor := spec.PreProcessor()
+	postProcessor := spec.PostProcessor()
+
+	args := make([]interface{}, 0, 6)
+	args = append(args, "testmetric", "active", "10ms", 5, 1, 0.1, 0.95, 0.5)
+	f, err := spec.CreateFilter(args)
+	if err != nil {
+		t.Fatalf("error creating filter: %v", err)
+		return
+	}
+	f.(*admissionControl).Close()
+
+	r := &eskip.Route{Filters: []*eskip.Filter{{Name: spec.Name(), Args: args}}, Backend: backend.URL}
+
+	fr := make(filters.Registry)
+	fr.Register(fspec)
+	fr.Register(builtin.NewSetRequestHeader())
+	fr.Register(builtin.NewStatus())
+
+	dc := testdataclient.New([]*eskip.Route{r})
+	defer dc.Close()
+
+	proxy := proxytest.WithParamsAndRoutingOptions(fr,
+		proxy.Params{
+			OpenTracing: &proxy.OpenTracingParams{Tracer: tracer},
+		},
+		routing.Options{
+			DataClients:    []routing.DataClient{dc},
+			PostProcessors: []routing.PostProcessor{postProcessor},
+			PreProcessors:  []routing.PreProcessor{preProcessor},
+		})
+	defer proxy.Close()
+
+	client := proxy.Client()
+	req, err := http.NewRequest("GET", proxy.URL, nil)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	_, err = client.Do(req)
+	if err != nil {
+		t.Error(err)
+	}
+
+	acSpanFound := false
+	finishedSpans := tracer.FinishedSpans()
+	for _, span := range finishedSpans {
+		if span.OperationName == "admission_control" {
+			acSpanFound = true
+			tags := span.Tags()
+
+			d, found := tags["admissionControl.d"]
+			assert.True(t, found)
+			assert.Equal(t, "10ms", d)
+
+			windowSize, found := tags["admissionControl.windowSize"]
+			assert.True(t, found)
+			assert.Equal(t, 5, windowSize)
+
+			group, found := tags["admissionControl.group"]
+			assert.True(t, found)
+			assert.Equal(t, "testmetric", group)
+
+			mode, found := tags["admissionControl.mode"]
+			assert.True(t, found)
+			assert.Equal(t, "active", mode)
+
+			mode, found = tags["mode"]
+			assert.True(t, found)
+			assert.Equal(t, "active", mode)
+		}
+	}
+	assert.True(t, acSpanFound)
+}
+
 type validationPostProcessorNumberOfFilters struct {
 	ch chan []*routing.Route
 }