-
Notifications
You must be signed in to change notification settings - Fork 395
/
watch_progress.go
128 lines (110 loc) · 3.03 KB
/
watch_progress.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
/*
Copyright 2023 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 cacher
import (
"context"
"sync"
"time"
"google.golang.org/grpc/metadata"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/klog/v2"
"k8s.io/utils/clock"
)
const (
// progressRequestPeriod determines period of requesting progress
// from etcd when there is a request waiting for watch cache to be fresh.
progressRequestPeriod = 100 * time.Millisecond
)
func newConditionalProgressRequester(requestWatchProgress WatchProgressRequester, clock TickerFactory, contextMetadata metadata.MD) *conditionalProgressRequester {
pr := &conditionalProgressRequester{
clock: clock,
requestWatchProgress: requestWatchProgress,
contextMetadata: contextMetadata,
}
pr.cond = sync.NewCond(pr.mux.RLocker())
return pr
}
type WatchProgressRequester func(ctx context.Context) error
type TickerFactory interface {
NewTicker(time.Duration) clock.Ticker
}
// conditionalProgressRequester will request progress notification if there
// is a request waiting for watch cache to be fresh.
type conditionalProgressRequester struct {
clock TickerFactory
requestWatchProgress WatchProgressRequester
contextMetadata metadata.MD
mux sync.RWMutex
cond *sync.Cond
waiting int
stopped bool
}
func (pr *conditionalProgressRequester) Run(stopCh <-chan struct{}) {
ctx := wait.ContextForChannel(stopCh)
if pr.contextMetadata != nil {
ctx = metadata.NewOutgoingContext(ctx, pr.contextMetadata)
}
go func() {
defer utilruntime.HandleCrash()
<-stopCh
pr.mux.Lock()
defer pr.mux.Unlock()
pr.stopped = true
pr.cond.Signal()
}()
ticker := pr.clock.NewTicker(progressRequestPeriod)
defer ticker.Stop()
for {
stopped := func() bool {
pr.mux.RLock()
defer pr.mux.RUnlock()
for pr.waiting == 0 && !pr.stopped {
pr.cond.Wait()
}
return pr.stopped
}()
if stopped {
return
}
select {
case <-ticker.C():
shouldRequest := func() bool {
pr.mux.RLock()
defer pr.mux.RUnlock()
return pr.waiting > 0 && !pr.stopped
}()
if !shouldRequest {
continue
}
err := pr.requestWatchProgress(ctx)
if err != nil {
klog.V(4).InfoS("Error requesting bookmark", "err", err)
}
case <-stopCh:
return
}
}
}
func (pr *conditionalProgressRequester) Add() {
pr.mux.Lock()
defer pr.mux.Unlock()
pr.waiting += 1
pr.cond.Signal()
}
func (pr *conditionalProgressRequester) Remove() {
pr.mux.Lock()
defer pr.mux.Unlock()
pr.waiting -= 1
pr.cond.Signal()
}