-
Notifications
You must be signed in to change notification settings - Fork 4.7k
/
controller.go
321 lines (285 loc) · 10.1 KB
/
controller.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
/*
Copyright 2015 The Kubernetes Authors All rights reserved.
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 framework
import (
"sync"
"time"
"k8s.io/kubernetes/pkg/client/cache"
"k8s.io/kubernetes/pkg/runtime"
utilruntime "k8s.io/kubernetes/pkg/util/runtime"
"k8s.io/kubernetes/pkg/util/wait"
)
// Config contains all the settings for a Controller.
type Config struct {
// The queue for your objects; either a cache.FIFO or
// a cache.DeltaFIFO. Your Process() function should accept
// the output of this Oueue's Pop() method.
cache.Queue
// Something that can list and watch your objects.
cache.ListerWatcher
// Something that can process your objects.
Process ProcessFunc
// The type of your objects.
ObjectType runtime.Object
// Reprocess everything at least this often.
// Note that if it takes longer for you to clear the queue than this
// period, you will end up processing items in the order determined
// by cache.FIFO.Replace(). Currently, this is random. If this is a
// problem, we can change that replacement policy to append new
// things to the end of the queue instead of replacing the entire
// queue.
FullResyncPeriod time.Duration
// If true, when Process() returns an error, re-enqueue the object.
// TODO: add interface to let you inject a delay/backoff or drop
// the object completely if desired. Pass the object in
// question to this interface as a parameter.
RetryOnError bool
}
// ProcessFunc processes a single object.
type ProcessFunc func(obj interface{}) error
// Controller is a generic controller framework.
type Controller struct {
config Config
reflector *cache.Reflector
reflectorMutex sync.RWMutex
}
// New makes a new Controller from the given Config.
func New(c *Config) *Controller {
ctlr := &Controller{
config: *c,
}
return ctlr
}
// Run begins processing items, and will continue until a value is sent down stopCh.
// It's an error to call Run more than once.
// Run blocks; call via go.
func (c *Controller) Run(stopCh <-chan struct{}) {
defer utilruntime.HandleCrash()
r := cache.NewReflector(
c.config.ListerWatcher,
c.config.ObjectType,
c.config.Queue,
c.config.FullResyncPeriod,
)
c.reflectorMutex.Lock()
c.reflector = r
c.reflectorMutex.Unlock()
r.RunUntil(stopCh)
wait.Until(c.processLoop, time.Second, stopCh)
}
// Returns true once this controller has completed an initial resource listing
func (c *Controller) HasSynced() bool {
return c.config.Queue.HasSynced()
}
// Requeue adds the provided object back into the queue if it does not already exist.
func (c *Controller) Requeue(obj interface{}) error {
return c.config.Queue.AddIfNotPresent(cache.Deltas{
cache.Delta{
Type: cache.Sync,
Object: obj,
},
})
}
// processLoop drains the work queue.
// TODO: Consider doing the processing in parallel. This will require a little thought
// to make sure that we don't end up processing the same object multiple times
// concurrently.
func (c *Controller) processLoop() {
for {
obj := c.config.Queue.Pop()
err := c.config.Process(obj)
if err != nil {
if c.config.RetryOnError {
// This is the safe way to re-enqueue.
c.config.Queue.AddIfNotPresent(obj)
}
}
}
}
// ResourceEventHandler can handle notifications for events that happen to a
// resource. The events are informational only, so you can't return an
// error.
// * OnAdd is called when an object is added.
// * OnUpdate is called when an object is modified. Note that oldObj is the
// last known state of the object-- it is possible that several changes
// were combined together, so you can't use this to see every single
// change. OnUpdate is also called when a re-list happens, and it will
// get called even if nothing changed. This is useful for periodically
// evaluating or syncing something.
// * OnDelete will get the final state of the item if it is known, otherwise
// it will get an object of type cache.DeletedFinalStateUnknown. This can
// happen if the watch is closed and misses the delete event and we don't
// notice the deletion until the subsequent re-list.
type ResourceEventHandler interface {
OnAdd(obj interface{})
OnUpdate(oldObj, newObj interface{})
OnDelete(obj interface{})
}
// ResourceEventHandlerFuncs is an adaptor to let you easily specify as many or
// as few of the notification functions as you want while still implementing
// ResourceEventHandler.
type ResourceEventHandlerFuncs struct {
AddFunc func(obj interface{})
UpdateFunc func(oldObj, newObj interface{})
DeleteFunc func(obj interface{})
}
// OnAdd calls AddFunc if it's not nil.
func (r ResourceEventHandlerFuncs) OnAdd(obj interface{}) {
if r.AddFunc != nil {
r.AddFunc(obj)
}
}
// OnUpdate calls UpdateFunc if it's not nil.
func (r ResourceEventHandlerFuncs) OnUpdate(oldObj, newObj interface{}) {
if r.UpdateFunc != nil {
r.UpdateFunc(oldObj, newObj)
}
}
// OnDelete calls DeleteFunc if it's not nil.
func (r ResourceEventHandlerFuncs) OnDelete(obj interface{}) {
if r.DeleteFunc != nil {
r.DeleteFunc(obj)
}
}
// DeletionHandlingMetaNamespaceKeyFunc checks for
// cache.DeletedFinalStateUnknown objects before calling
// cache.MetaNamespaceKeyFunc.
func DeletionHandlingMetaNamespaceKeyFunc(obj interface{}) (string, error) {
if d, ok := obj.(cache.DeletedFinalStateUnknown); ok {
return d.Key, nil
}
return cache.MetaNamespaceKeyFunc(obj)
}
// NewInformer returns a cache.Store and a controller for populating the store
// while also providing event notifications. You should only used the returned
// cache.Store for Get/List operations; Add/Modify/Deletes will cause the event
// notifications to be faulty.
//
// Parameters:
// * lw is list and watch functions for the source of the resource you want to
// be informed of.
// * objType is an object of the type that you expect to receive.
// * resyncPeriod: if non-zero, will re-list this often (you will get OnUpdate
// calls, even if nothing changed). Otherwise, re-list will be delayed as
// long as possible (until the upstream source closes the watch or times out,
// or you stop the controller).
// * h is the object you want notifications sent to.
//
func NewInformer(
lw cache.ListerWatcher,
objType runtime.Object,
resyncPeriod time.Duration,
h ResourceEventHandler,
) (cache.Store, *Controller) {
// This will hold the client state, as we know it.
clientState := cache.NewStore(DeletionHandlingMetaNamespaceKeyFunc)
// This will hold incoming changes. Note how we pass clientState in as a
// KeyLister, that way resync operations will result in the correct set
// of update/delete deltas.
fifo := cache.NewDeltaFIFO(cache.MetaNamespaceKeyFunc, nil, clientState)
cfg := &Config{
Queue: fifo,
ListerWatcher: lw,
ObjectType: objType,
FullResyncPeriod: resyncPeriod,
RetryOnError: false,
Process: func(obj interface{}) error {
// from oldest to newest
for _, d := range obj.(cache.Deltas) {
switch d.Type {
case cache.Sync, cache.Added, cache.Updated:
if old, exists, err := clientState.Get(d.Object); err == nil && exists {
if err := clientState.Update(d.Object); err != nil {
return err
}
h.OnUpdate(old, d.Object)
} else {
if err := clientState.Add(d.Object); err != nil {
return err
}
h.OnAdd(d.Object)
}
case cache.Deleted:
if err := clientState.Delete(d.Object); err != nil {
return err
}
h.OnDelete(d.Object)
}
}
return nil
},
}
return clientState, New(cfg)
}
// NewIndexerInformer returns a cache.Indexer and a controller for populating the index
// while also providing event notifications. You should only used the returned
// cache.Index for Get/List operations; Add/Modify/Deletes will cause the event
// notifications to be faulty.
//
// Parameters:
// * lw is list and watch functions for the source of the resource you want to
// be informed of.
// * objType is an object of the type that you expect to receive.
// * resyncPeriod: if non-zero, will re-list this often (you will get OnUpdate
// calls, even if nothing changed). Otherwise, re-list will be delayed as
// long as possible (until the upstream source closes the watch or times out,
// or you stop the controller).
// * h is the object you want notifications sent to.
//
func NewIndexerInformer(
lw cache.ListerWatcher,
objType runtime.Object,
resyncPeriod time.Duration,
h ResourceEventHandler,
indexers cache.Indexers,
) (cache.Indexer, *Controller) {
// This will hold the client state, as we know it.
clientState := cache.NewIndexer(DeletionHandlingMetaNamespaceKeyFunc, indexers)
// This will hold incoming changes. Note how we pass clientState in as a
// KeyLister, that way resync operations will result in the correct set
// of update/delete deltas.
fifo := cache.NewDeltaFIFO(cache.MetaNamespaceKeyFunc, nil, clientState)
cfg := &Config{
Queue: fifo,
ListerWatcher: lw,
ObjectType: objType,
FullResyncPeriod: resyncPeriod,
RetryOnError: false,
Process: func(obj interface{}) error {
// from oldest to newest
for _, d := range obj.(cache.Deltas) {
switch d.Type {
case cache.Sync, cache.Added, cache.Updated:
if old, exists, err := clientState.Get(d.Object); err == nil && exists {
if err := clientState.Update(d.Object); err != nil {
return err
}
h.OnUpdate(old, d.Object)
} else {
if err := clientState.Add(d.Object); err != nil {
return err
}
h.OnAdd(d.Object)
}
case cache.Deleted:
if err := clientState.Delete(d.Object); err != nil {
return err
}
h.OnDelete(d.Object)
}
}
return nil
},
}
return clientState, New(cfg)
}