-
Notifications
You must be signed in to change notification settings - Fork 39.2k
/
watch.go
executable file
·324 lines (284 loc) · 9.71 KB
/
watch.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
/*
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 handlers
import (
"bytes"
"fmt"
"net/http"
"reflect"
"time"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/serializer/streaming"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/apiserver/pkg/endpoints/handlers/negotiation"
"k8s.io/apiserver/pkg/endpoints/metrics"
"k8s.io/apiserver/pkg/endpoints/request"
"k8s.io/apiserver/pkg/server/httplog"
"k8s.io/apiserver/pkg/util/wsstream"
"golang.org/x/net/websocket"
)
// nothing will ever be sent down this channel
var neverExitWatch <-chan time.Time = make(chan time.Time)
// timeoutFactory abstracts watch timeout logic for testing
type TimeoutFactory interface {
TimeoutCh() (<-chan time.Time, func() bool)
}
// realTimeoutFactory implements timeoutFactory
type realTimeoutFactory struct {
timeout time.Duration
}
// TimeoutCh returns a channel which will receive something when the watch times out,
// and a cleanup function to call when this happens.
func (w *realTimeoutFactory) TimeoutCh() (<-chan time.Time, func() bool) {
if w.timeout == 0 {
return neverExitWatch, func() bool { return false }
}
t := time.NewTimer(w.timeout)
return t.C, t.Stop
}
// serveWatch handles serving requests to the server
// TODO: the functionality in this method and in WatchServer.Serve is not cleanly decoupled.
func serveWatch(watcher watch.Interface, scope RequestScope, req *http.Request, w http.ResponseWriter, timeout time.Duration) {
// negotiate for the stream serializer
serializer, err := negotiation.NegotiateOutputStreamSerializer(req, scope.Serializer)
if err != nil {
scope.err(err, w, req)
return
}
framer := serializer.StreamSerializer.Framer
streamSerializer := serializer.StreamSerializer.Serializer
embedded := serializer.Serializer
if framer == nil {
scope.err(fmt.Errorf("no framer defined for %q available for embedded encoding", serializer.MediaType), w, req)
return
}
encoder := scope.Serializer.EncoderForVersion(streamSerializer, scope.Kind.GroupVersion())
useTextFraming := serializer.EncodesAsText
// find the embedded serializer matching the media type
embeddedEncoder := scope.Serializer.EncoderForVersion(embedded, scope.Kind.GroupVersion())
// TODO: next step, get back mediaTypeOptions from negotiate and return the exact value here
mediaType := serializer.MediaType
if mediaType != runtime.ContentTypeJSON {
mediaType += ";stream=watch"
}
ctx := req.Context()
requestInfo, ok := request.RequestInfoFrom(ctx)
if !ok {
scope.err(fmt.Errorf("missing requestInfo"), w, req)
return
}
server := &WatchServer{
Watching: watcher,
Scope: scope,
UseTextFraming: useTextFraming,
MediaType: mediaType,
Framer: framer,
Encoder: encoder,
EmbeddedEncoder: embeddedEncoder,
Fixup: func(obj runtime.Object) {
if err := setSelfLink(obj, requestInfo, scope.Namer); err != nil {
utilruntime.HandleError(fmt.Errorf("failed to set link for object %v: %v", reflect.TypeOf(obj), err))
}
},
TimeoutFactory: &realTimeoutFactory{timeout},
}
server.ServeHTTP(w, req)
}
// WatchServer serves a watch.Interface over a websocket or vanilla HTTP.
type WatchServer struct {
Watching watch.Interface
Scope RequestScope
// true if websocket messages should use text framing (as opposed to binary framing)
UseTextFraming bool
// the media type this watch is being served with
MediaType string
// used to frame the watch stream
Framer runtime.Framer
// used to encode the watch stream event itself
Encoder runtime.Encoder
// used to encode the nested object in the watch stream
EmbeddedEncoder runtime.Encoder
Fixup func(runtime.Object)
TimeoutFactory TimeoutFactory
}
// ServeHTTP serves a series of encoded events via HTTP with Transfer-Encoding: chunked
// or over a websocket connection.
func (s *WatchServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
kind := s.Scope.Kind
metrics.RegisteredWatchers.WithLabelValues(kind.Group, kind.Version, kind.Kind).Inc()
defer metrics.RegisteredWatchers.WithLabelValues(kind.Group, kind.Version, kind.Kind).Dec()
w = httplog.Unlogged(w)
if wsstream.IsWebSocketRequest(req) {
w.Header().Set("Content-Type", s.MediaType)
websocket.Handler(s.HandleWS).ServeHTTP(w, req)
return
}
cn, ok := w.(http.CloseNotifier)
if !ok {
err := fmt.Errorf("unable to start watch - can't get http.CloseNotifier: %#v", w)
utilruntime.HandleError(err)
s.Scope.err(errors.NewInternalError(err), w, req)
return
}
flusher, ok := w.(http.Flusher)
if !ok {
err := fmt.Errorf("unable to start watch - can't get http.Flusher: %#v", w)
utilruntime.HandleError(err)
s.Scope.err(errors.NewInternalError(err), w, req)
return
}
framer := s.Framer.NewFrameWriter(w)
if framer == nil {
// programmer error
err := fmt.Errorf("no stream framing support is available for media type %q", s.MediaType)
utilruntime.HandleError(err)
s.Scope.err(errors.NewBadRequest(err.Error()), w, req)
return
}
e := streaming.NewEncoder(framer, s.Encoder)
// ensure the connection times out
timeoutCh, cleanup := s.TimeoutFactory.TimeoutCh()
defer cleanup()
defer s.Watching.Stop()
// begin the stream
w.Header().Set("Content-Type", s.MediaType)
w.Header().Set("Transfer-Encoding", "chunked")
w.WriteHeader(http.StatusOK)
flusher.Flush()
var unknown runtime.Unknown
internalEvent := &metav1.InternalEvent{}
buf := &bytes.Buffer{}
ch := s.Watching.ResultChan()
for {
select {
case <-cn.CloseNotify():
return
case <-timeoutCh:
return
case event, ok := <-ch:
if !ok {
// End of results.
return
}
obj := event.Object
s.Fixup(obj)
if err := s.EmbeddedEncoder.Encode(obj, buf); err != nil {
// unexpected error
utilruntime.HandleError(fmt.Errorf("unable to encode watch object %T: %v", obj, err))
return
}
// ContentType is not required here because we are defaulting to the serializer
// type
unknown.Raw = buf.Bytes()
event.Object = &unknown
// create the external type directly and encode it. Clients will only recognize the serialization we provide.
// The internal event is being reused, not reallocated so its just a few extra assignments to do it this way
// and we get the benefit of using conversion functions which already have to stay in sync
outEvent := &metav1.WatchEvent{}
*internalEvent = metav1.InternalEvent(event)
err := metav1.Convert_v1_InternalEvent_To_v1_WatchEvent(internalEvent, outEvent, nil)
if err != nil {
utilruntime.HandleError(fmt.Errorf("unable to convert watch object: %v", err))
// client disconnect.
return
}
if err := e.Encode(outEvent); err != nil {
utilruntime.HandleError(fmt.Errorf("unable to encode watch object %T: %v (%#v)", outEvent, err, e))
// client disconnect.
return
}
if len(ch) == 0 {
flusher.Flush()
}
buf.Reset()
}
}
}
// HandleWS implements a websocket handler.
func (s *WatchServer) HandleWS(ws *websocket.Conn) {
defer ws.Close()
done := make(chan struct{})
go func() {
defer utilruntime.HandleCrash()
// This blocks until the connection is closed.
// Client should not send anything.
wsstream.IgnoreReceives(ws, 0)
// Once the client closes, we should also close
close(done)
}()
var unknown runtime.Unknown
internalEvent := &metav1.InternalEvent{}
buf := &bytes.Buffer{}
streamBuf := &bytes.Buffer{}
ch := s.Watching.ResultChan()
for {
select {
case <-done:
s.Watching.Stop()
return
case event, ok := <-ch:
if !ok {
// End of results.
return
}
obj := event.Object
s.Fixup(obj)
if err := s.EmbeddedEncoder.Encode(obj, buf); err != nil {
// unexpected error
utilruntime.HandleError(fmt.Errorf("unable to encode watch object %T: %v", obj, err))
return
}
// ContentType is not required here because we are defaulting to the serializer
// type
unknown.Raw = buf.Bytes()
event.Object = &unknown
// the internal event will be versioned by the encoder
// create the external type directly and encode it. Clients will only recognize the serialization we provide.
// The internal event is being reused, not reallocated so its just a few extra assignments to do it this way
// and we get the benefit of using conversion functions which already have to stay in sync
outEvent := &metav1.WatchEvent{}
*internalEvent = metav1.InternalEvent(event)
err := metav1.Convert_v1_InternalEvent_To_v1_WatchEvent(internalEvent, outEvent, nil)
if err != nil {
utilruntime.HandleError(fmt.Errorf("unable to convert watch object: %v", err))
// client disconnect.
s.Watching.Stop()
return
}
if err := s.Encoder.Encode(outEvent, streamBuf); err != nil {
// encoding error
utilruntime.HandleError(fmt.Errorf("unable to encode event: %v", err))
s.Watching.Stop()
return
}
if s.UseTextFraming {
if err := websocket.Message.Send(ws, streamBuf.String()); err != nil {
// Client disconnect.
s.Watching.Stop()
return
}
} else {
if err := websocket.Message.Send(ws, streamBuf.Bytes()); err != nil {
// Client disconnect.
s.Watching.Stop()
return
}
}
buf.Reset()
streamBuf.Reset()
}
}
}