forked from projectcalico/typha
/
jittered_ticker.go
78 lines (70 loc) · 1.92 KB
/
jittered_ticker.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
// Copyright (c) 2016-2017 Tigera, Inc. 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 jitter
import (
"math/rand"
"time"
log "github.com/sirupsen/logrus"
)
// Ticker tries to emit events on channel C at minDuration intervals plus up to maxJitter.
type Ticker struct {
C <-chan time.Time
stop chan struct{}
MinDuration time.Duration
MaxJitter time.Duration
}
func NewTicker(minDuration time.Duration, maxJitter time.Duration) *Ticker {
if minDuration < 0 {
log.WithField("duration", minDuration).Panic("Negative duration")
}
if maxJitter < 0 {
log.WithField("jitter", minDuration).Panic("Negative jitter")
}
c := make(chan time.Time, 1)
ticker := &Ticker{
C: c,
stop: make(chan struct{}),
MinDuration: minDuration,
MaxJitter: maxJitter,
}
go ticker.loop(c)
return ticker
}
func (t *Ticker) loop(c chan time.Time) {
timer := time.NewTimer(t.calculateDelay())
var outCOrNil chan time.Time
tickLoop:
for {
select {
case <-t.stop:
log.Info("Stopping jittered ticker")
close(c)
timer.Stop()
break tickLoop
case <-timer.C:
outCOrNil = c
timer.Reset(t.calculateDelay())
case outCOrNil <- time.Now():
outCOrNil = nil
}
}
}
func (t *Ticker) calculateDelay() time.Duration {
jitter := time.Duration(rand.Int63n(int64(t.MaxJitter)))
delay := t.MinDuration + jitter
return delay
}
func (t *Ticker) Stop() {
close(t.stop)
}