-
Notifications
You must be signed in to change notification settings - Fork 2.3k
/
metrics.go
120 lines (104 loc) · 3.01 KB
/
metrics.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
// Copyright (c) 2020 The Jaeger 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 httpmetrics
import (
"net/http"
"strconv"
"sync"
"time"
"github.com/uber/jaeger-lib/metrics"
)
type statusRecorder struct {
http.ResponseWriter
status int
wroteHeader bool
}
func (r *statusRecorder) WriteHeader(status int) {
if r.wroteHeader {
return
}
r.status = status
r.wroteHeader = true
r.ResponseWriter.WriteHeader(status)
}
// Wrap returns a handler that wraps the provided one and emits metrics based on the HTTP requests and responses.
// It will record the HTTP response status, HTTP method, duration and path of the call.
// The duration will be reported in metrics.Timer and the rest will be labels on that timer.
//
// Do not use with HTTP endpoints that take parameters from URL path, such as `/user/{user_id}`,
// because they will result in high cardinality metrics.
func Wrap(h http.Handler, metricsFactory metrics.Factory) http.Handler {
timers := newRequestDurations(metricsFactory)
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
start := time.Now()
recorder := &statusRecorder{ResponseWriter: w}
h.ServeHTTP(recorder, r)
req := recordedRequest{
key: recordedRequestKey{
status: strconv.Itoa(recorder.status),
path: r.URL.Path,
method: r.Method,
},
duration: time.Since(start),
}
timers.record(req)
})
}
type recordedRequestKey struct {
method string
path string
status string
}
type recordedRequest struct {
key recordedRequestKey
duration time.Duration
}
type requestDurations struct {
lock sync.RWMutex
metrics metrics.Factory
timers map[recordedRequestKey]metrics.Timer
}
func newRequestDurations(metricsFactory metrics.Factory) *requestDurations {
return &requestDurations{
timers: make(map[recordedRequestKey]metrics.Timer),
metrics: metricsFactory,
}
}
func (r *requestDurations) record(request recordedRequest) {
cacheKey := request.key
r.lock.RLock()
timer, ok := r.timers[cacheKey]
r.lock.RUnlock()
if !ok {
r.lock.Lock()
timer, ok = r.timers[cacheKey]
if !ok {
timer = buildTimer(r.metrics, cacheKey)
r.timers[cacheKey] = timer
}
r.lock.Unlock()
}
timer.Record(request.duration)
}
func buildTimer(metricsFactory metrics.Factory, key recordedRequestKey) metrics.Timer {
return metricsFactory.Timer(metrics.TimerOptions{
Name: "http.request.duration",
Help: "Duration of HTTP requests",
Tags: map[string]string{
"status": key.status,
"path": key.path,
"method": key.method,
},
})
}