/
instrument_client_test.go
389 lines (338 loc) · 11 KB
/
instrument_client_test.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
// 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()
}