generated from cloudwego/.github
-
Notifications
You must be signed in to change notification settings - Fork 3
/
limiter.go
68 lines (59 loc) · 1.77 KB
/
limiter.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
// Copyright 2023 CloudWeGo 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 util
import (
"sync/atomic"
"time"
"github.com/cloudwego/configmanager/iface"
)
var _ iface.Limiter = (*FrequencyLimiter)(nil)
// FrequencyLimiter is used to limit the frequency of any action.
type FrequencyLimiter struct {
allowed int32
remain int32
interval time.Duration
exit int32
}
// NewFrequencyLimiter creates a new FrequencyLimiter with the given interval and allowed count.
func NewFrequencyLimiter(interval time.Duration, allowed int32) *FrequencyLimiter {
if interval <= 0 {
panic("interval must be positive")
}
l := &FrequencyLimiter{
allowed: allowed,
remain: allowed,
interval: interval,
}
go l.refresh()
return l
}
// Stop stops the refresh of this limiter.
func (l *FrequencyLimiter) Stop() {
atomic.StoreInt32(&l.exit, 1)
}
// refresh refreshes remain count atomically for each interval passed.
func (l *FrequencyLimiter) refresh() {
ticker := time.NewTicker(l.interval)
defer ticker.Stop()
for range ticker.C {
atomic.StoreInt32(&l.remain, l.allowed)
if atomic.LoadInt32(&l.exit) == 1 {
return
}
}
}
// Allow returns true if the action is allowed.
func (l *FrequencyLimiter) Allow() bool {
return atomic.AddInt32(&l.remain, -1) >= 0
}