-
Notifications
You must be signed in to change notification settings - Fork 400
/
httplog.go
243 lines (208 loc) · 6.78 KB
/
httplog.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
/*
Copyright 2014 The Kubernetes 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 httplog
import (
"bufio"
"context"
"fmt"
"net"
"net/http"
"runtime"
"time"
"k8s.io/klog/v2"
)
// StacktracePred returns true if a stacktrace should be logged for this status.
type StacktracePred func(httpStatus int) (logStacktrace bool)
type logger interface {
Addf(format string, data ...interface{})
}
type respLoggerContextKeyType int
// respLoggerContextKey is used to store the respLogger pointer in the request context.
const respLoggerContextKey respLoggerContextKeyType = iota
// Add a layer on top of ResponseWriter, so we can track latency and error
// message sources.
//
// TODO now that we're using go-restful, we shouldn't need to be wrapping
// the http.ResponseWriter. We can recover panics from go-restful, and
// the logging value is questionable.
type respLogger struct {
hijacked bool
statusRecorded bool
status int
statusStack string
addedInfo string
startTime time.Time
captureErrorOutput bool
req *http.Request
w http.ResponseWriter
logStacktracePred StacktracePred
}
// Simple logger that logs immediately when Addf is called
type passthroughLogger struct{}
// Addf logs info immediately.
func (passthroughLogger) Addf(format string, data ...interface{}) {
klog.V(2).Info(fmt.Sprintf(format, data...))
}
// DefaultStacktracePred is the default implementation of StacktracePred.
func DefaultStacktracePred(status int) bool {
return (status < http.StatusOK || status >= http.StatusInternalServerError) && status != http.StatusSwitchingProtocols
}
// WithLogging wraps the handler with logging.
func WithLogging(handler http.Handler, pred StacktracePred) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
if old := respLoggerFromContext(req); old != nil {
panic("multiple WithLogging calls!")
}
rl := newLogged(req, w).StacktraceWhen(pred)
req = req.WithContext(context.WithValue(ctx, respLoggerContextKey, rl))
if klog.V(3).Enabled() {
defer func() { klog.InfoS("HTTP", rl.LogArgs()...) }()
}
handler.ServeHTTP(rl, req)
})
}
// respLoggerFromContext returns the respLogger or nil.
func respLoggerFromContext(req *http.Request) *respLogger {
ctx := req.Context()
val := ctx.Value(respLoggerContextKey)
if rl, ok := val.(*respLogger); ok {
return rl
}
return nil
}
// newLogged turns a normal response writer into a logged response writer.
func newLogged(req *http.Request, w http.ResponseWriter) *respLogger {
return &respLogger{
startTime: time.Now(),
req: req,
w: w,
logStacktracePred: DefaultStacktracePred,
}
}
// LogOf returns the logger hiding in w. If there is not an existing logger
// then a passthroughLogger will be created which will log to stdout immediately
// when Addf is called.
func LogOf(req *http.Request, w http.ResponseWriter) logger {
if rl := respLoggerFromContext(req); rl != nil {
return rl
}
return &passthroughLogger{}
}
// Unlogged returns the original ResponseWriter, or w if it is not our inserted logger.
func Unlogged(req *http.Request, w http.ResponseWriter) http.ResponseWriter {
if rl := respLoggerFromContext(req); rl != nil {
return rl.w
}
return w
}
// StacktraceWhen sets the stacktrace logging predicate, which decides when to log a stacktrace.
// There's a default, so you don't need to call this unless you don't like the default.
func (rl *respLogger) StacktraceWhen(pred StacktracePred) *respLogger {
rl.logStacktracePred = pred
return rl
}
// StatusIsNot returns a StacktracePred which will cause stacktraces to be logged
// for any status *not* in the given list.
func StatusIsNot(statuses ...int) StacktracePred {
statusesNoTrace := map[int]bool{}
for _, s := range statuses {
statusesNoTrace[s] = true
}
return func(status int) bool {
_, ok := statusesNoTrace[status]
return !ok
}
}
// Addf adds additional data to be logged with this request.
func (rl *respLogger) Addf(format string, data ...interface{}) {
rl.addedInfo += "\n" + fmt.Sprintf(format, data...)
}
func (rl *respLogger) LogArgs() []interface{} {
latency := time.Since(rl.startTime)
if rl.hijacked {
return []interface{}{
"verb", rl.req.Method,
"URI", rl.req.RequestURI,
"latency", latency,
"userAgent", rl.req.UserAgent(),
"srcIP", rl.req.RemoteAddr,
"hijacked", true,
}
}
args := []interface{}{
"verb", rl.req.Method,
"URI", rl.req.RequestURI,
"latency", latency,
"userAgent", rl.req.UserAgent(),
"srcIP", rl.req.RemoteAddr,
"resp", rl.status,
}
if len(rl.statusStack) > 0 {
args = append(args, "statusStack", rl.statusStack)
}
if len(rl.addedInfo) > 0 {
args = append(args, "addedInfo", rl.addedInfo)
}
return args
}
// Header implements http.ResponseWriter.
func (rl *respLogger) Header() http.Header {
return rl.w.Header()
}
// Write implements http.ResponseWriter.
func (rl *respLogger) Write(b []byte) (int, error) {
if !rl.statusRecorded {
rl.recordStatus(http.StatusOK) // Default if WriteHeader hasn't been called
}
if rl.captureErrorOutput {
rl.Addf("logging error output: %q\n", string(b))
}
return rl.w.Write(b)
}
// Flush implements http.Flusher even if the underlying http.Writer doesn't implement it.
// Flush is used for streaming purposes and allows to flush buffered data to the client.
func (rl *respLogger) Flush() {
if flusher, ok := rl.w.(http.Flusher); ok {
flusher.Flush()
} else if klog.V(2).Enabled() {
klog.InfoDepth(1, fmt.Sprintf("Unable to convert %+v into http.Flusher", rl.w))
}
}
// WriteHeader implements http.ResponseWriter.
func (rl *respLogger) WriteHeader(status int) {
rl.recordStatus(status)
rl.w.WriteHeader(status)
}
// Hijack implements http.Hijacker.
func (rl *respLogger) Hijack() (net.Conn, *bufio.ReadWriter, error) {
rl.hijacked = true
return rl.w.(http.Hijacker).Hijack()
}
// CloseNotify implements http.CloseNotifier
func (rl *respLogger) CloseNotify() <-chan bool {
return rl.w.(http.CloseNotifier).CloseNotify()
}
func (rl *respLogger) recordStatus(status int) {
rl.status = status
rl.statusRecorded = true
if rl.logStacktracePred(status) {
// Only log stacks for errors
stack := make([]byte, 50*1024)
stack = stack[:runtime.Stack(stack, false)]
rl.statusStack = "\n" + string(stack)
rl.captureErrorOutput = true
} else {
rl.statusStack = ""
}
}