client_golang/prometheus/promhttp/instrument_client_test.go

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// Copyright 2017 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package promhttp
import (
"context"
"log"
"net/http"
"net/http/httptest"
"reflect"
"sort"
"strings"
"testing"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/testutil"
dto "github.com/prometheus/client_model/go"
"google.golang.org/protobuf/proto"
)
func makeInstrumentedClient(opts ...Option) (*http.Client, *prometheus.Registry) {
client := http.DefaultClient
client.Timeout = 1 * time.Second
reg := prometheus.NewRegistry()
inFlightGauge := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "client_in_flight_requests",
Help: "A gauge of in-flight requests for the wrapped client.",
})
counter := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "client_api_requests_total",
Help: "A counter for requests from the wrapped client.",
},
[]string{"code", "method"},
)
dnsLatencyVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "dns_duration_seconds",
Help: "Trace dns latency histogram.",
Buckets: []float64{.005, .01, .025, .05},
},
[]string{"event"},
)
tlsLatencyVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "tls_duration_seconds",
Help: "Trace tls latency histogram.",
Buckets: []float64{.05, .1, .25, .5},
},
[]string{"event"},
)
histVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "request_duration_seconds",
Help: "A histogram of request latencies.",
Buckets: prometheus.DefBuckets,
},
[]string{"method"},
)
reg.MustRegister(counter, tlsLatencyVec, dnsLatencyVec, histVec, inFlightGauge)
trace := &InstrumentTrace{
DNSStart: func(t float64) {
dnsLatencyVec.WithLabelValues("dns_start").Observe(t)
},
DNSDone: func(t float64) {
dnsLatencyVec.WithLabelValues("dns_done").Observe(t)
},
TLSHandshakeStart: func(t float64) {
tlsLatencyVec.WithLabelValues("tls_handshake_start").Observe(t)
},
TLSHandshakeDone: func(t float64) {
tlsLatencyVec.WithLabelValues("tls_handshake_done").Observe(t)
},
}
client.Transport = InstrumentRoundTripperInFlight(inFlightGauge,
InstrumentRoundTripperCounter(counter,
InstrumentRoundTripperTrace(trace,
InstrumentRoundTripperDuration(histVec, http.DefaultTransport, opts...),
),
opts...),
)
return client, reg
}
func labelsToLabelPair(l prometheus.Labels) []*dto.LabelPair {
ret := make([]*dto.LabelPair, 0, len(l))
for k, v := range l {
ret = append(ret, &dto.LabelPair{Name: proto.String(k), Value: proto.String(v)})
}
sort.Slice(ret, func(i, j int) bool {
return *ret[i].Name < *ret[j].Name
})
return ret
}
func assetMetricAndExemplars(
t *testing.T,
reg *prometheus.Registry,
expectedNumMetrics int,
expectedExemplar []*dto.LabelPair,
) {
t.Helper()
mfs, err := reg.Gather()
if err != nil {
t.Fatal(err)
}
if want, got := expectedNumMetrics, len(mfs); want != got {
t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
}
for _, mf := range mfs {
if len(mf.Metric) == 0 {
t.Errorf("metric family %s must not be empty", mf.GetName())
}
for _, m := range mf.GetMetric() {
if c := m.GetCounter(); c != nil {
if len(expectedExemplar) == 0 {
if c.Exemplar != nil {
t.Errorf("expected no exemplar on the counter %v%v, got %v", mf.GetName(), m.Label, c.Exemplar.String())
}
continue
}
if c.Exemplar == nil {
t.Errorf("expected exemplar %v on the counter %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
continue
}
if got := c.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
t.Errorf("expected exemplar %v on the counter %v%v, got %v", expectedExemplar, mf.GetName(), m.Label, got)
}
continue
}
if h := m.GetHistogram(); h != nil {
found := false
for _, b := range h.GetBucket() {
if len(expectedExemplar) == 0 {
if b.Exemplar != nil {
t.Errorf("expected no exemplar on histogram %v%v bkt %v, got %v", mf.GetName(), m.Label, b.GetUpperBound(), b.Exemplar.String())
}
continue
}
if b.Exemplar == nil {
continue
}
if got := b.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
t.Errorf("expected exemplar %v on the histogram %v%v on bkt %v, got %v", expectedExemplar, mf.GetName(), m.Label, b.GetUpperBound(), got)
continue
}
found = true
break
}
if len(expectedExemplar) > 0 && !found {
t.Errorf("expected exemplar %v on at least one bucket of the histogram %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
}
}
}
}
}
func TestClientMiddlewareAPI(t *testing.T) {
client, reg := makeInstrumentedClient()
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
defer backend.Close()
resp, err := client.Get(backend.URL)
if err != nil {
t.Fatal(err)
}
defer resp.Body.Close()
assetMetricAndExemplars(t, reg, 3, nil)
}
func TestClientMiddlewareAPI_WithExemplars(t *testing.T) {
exemplar := prometheus.Labels{"traceID": "example situation observed by this metric"}
client, reg := makeInstrumentedClient(WithExemplarFromContext(func(_ context.Context) prometheus.Labels { return exemplar }))
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
defer backend.Close()
resp, err := client.Get(backend.URL)
if err != nil {
t.Fatal(err)
}
defer resp.Body.Close()
assetMetricAndExemplars(t, reg, 3, labelsToLabelPair(exemplar))
}
func TestClientMiddlewareAPI_WithRequestContext(t *testing.T) {
client, reg := makeInstrumentedClient()
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
defer backend.Close()
req, err := http.NewRequest("GET", backend.URL, nil)
if err != nil {
t.Fatalf("%v", err)
}
// Set a context with a long timeout.
ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
t.Fatal(err)
}
defer resp.Body.Close()
mfs, err := reg.Gather()
if err != nil {
t.Fatal(err)
}
if want, got := 3, len(mfs); want != got {
t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
}
for _, mf := range mfs {
if len(mf.Metric) == 0 {
t.Errorf("metric family %s must not be empty", mf.GetName())
}
}
// make sure counters aren't double-incremented (see #1117)
expected := `
# HELP client_api_requests_total A counter for requests from the wrapped client.
# TYPE client_api_requests_total counter
client_api_requests_total{code="200",method="get"} 1
`
if err := testutil.GatherAndCompare(reg, strings.NewReader(expected),
"client_api_requests_total",
); err != nil {
t.Fatal(err)
}
}
func TestClientMiddlewareAPIWithRequestContextTimeout(t *testing.T) {
client, _ := makeInstrumentedClient()
// Slow testserver responding in 100ms.
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
time.Sleep(100 * time.Millisecond)
w.WriteHeader(http.StatusOK)
}))
defer backend.Close()
req, err := http.NewRequest("GET", backend.URL, nil)
if err != nil {
t.Fatalf("%v", err)
}
// Set a context with a short timeout.
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
defer cancel()
req = req.WithContext(ctx)
_, err = client.Do(req)
if err == nil {
t.Fatal("did not get timeout error")
}
expectedMsg := "context deadline exceeded"
if !strings.Contains(err.Error(), expectedMsg) {
t.Fatalf("unexpected error: %q, expect error: %q", err.Error(), expectedMsg)
}
}
func ExampleInstrumentRoundTripperDuration() {
client := http.DefaultClient
client.Timeout = 1 * time.Second
inFlightGauge := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "client_in_flight_requests",
Help: "A gauge of in-flight requests for the wrapped client.",
})
counter := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "client_api_requests_total",
Help: "A counter for requests from the wrapped client.",
},
[]string{"code", "method"},
)
// dnsLatencyVec uses custom buckets based on expected dns durations.
// It has an instance label "event", which is set in the
// DNSStart and DNSDonehook functions defined in the
// InstrumentTrace struct below.
dnsLatencyVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "dns_duration_seconds",
Help: "Trace dns latency histogram.",
Buckets: []float64{.005, .01, .025, .05},
},
[]string{"event"},
)
// tlsLatencyVec uses custom buckets based on expected tls durations.
// It has an instance label "event", which is set in the
// TLSHandshakeStart and TLSHandshakeDone hook functions defined in the
// InstrumentTrace struct below.
tlsLatencyVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "tls_duration_seconds",
Help: "Trace tls latency histogram.",
Buckets: []float64{.05, .1, .25, .5},
},
[]string{"event"},
)
// histVec has no labels, making it a zero-dimensional ObserverVec.
histVec := prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "request_duration_seconds",
Help: "A histogram of request latencies.",
Buckets: prometheus.DefBuckets,
},
[]string{},
)
// Register all of the metrics in the standard registry.
prometheus.MustRegister(counter, tlsLatencyVec, dnsLatencyVec, histVec, inFlightGauge)
// Define functions for the available httptrace.ClientTrace hook
// functions that we want to instrument.
trace := &InstrumentTrace{
DNSStart: func(t float64) {
dnsLatencyVec.WithLabelValues("dns_start").Observe(t)
},
DNSDone: func(t float64) {
dnsLatencyVec.WithLabelValues("dns_done").Observe(t)
},
TLSHandshakeStart: func(t float64) {
tlsLatencyVec.WithLabelValues("tls_handshake_start").Observe(t)
},
TLSHandshakeDone: func(t float64) {
tlsLatencyVec.WithLabelValues("tls_handshake_done").Observe(t)
},
}
// Wrap the default RoundTripper with middleware.
roundTripper := InstrumentRoundTripperInFlight(inFlightGauge,
InstrumentRoundTripperCounter(counter,
InstrumentRoundTripperTrace(trace,
InstrumentRoundTripperDuration(histVec, http.DefaultTransport),
),
),
)
// Set the RoundTripper on our client.
client.Transport = roundTripper
resp, err := client.Get("http://google.com")
if err != nil {
log.Printf("error: %v", err)
}
defer resp.Body.Close()
}