-
Notifications
You must be signed in to change notification settings - Fork 0
/
weight_random.go
109 lines (91 loc) · 2.66 KB
/
weight_random.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
/*
* Copyright 2022 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 loadbalance
import (
"sync"
"github.com/bytedance/gopkg/lang/fastrand"
"github.com/liaogang/hertz/pkg/app/client/discovery"
"github.com/liaogang/hertz/pkg/common/hlog"
"golang.org/x/sync/singleflight"
)
type weightedBalancer struct {
cachedWeightInfo sync.Map
sfg singleflight.Group
}
type weightInfo struct {
instances []discovery.Instance
entries []int
weightSum int
}
// NewWeightedBalancer creates a loadbalancer using weighted-random algorithm.
func NewWeightedBalancer() Loadbalancer {
lb := &weightedBalancer{}
return lb
}
func (wb *weightedBalancer) calcWeightInfo(e discovery.Result) *weightInfo {
w := &weightInfo{
instances: make([]discovery.Instance, len(e.Instances)),
weightSum: 0,
entries: make([]int, len(e.Instances)),
}
var cnt int
for idx := range e.Instances {
weight := e.Instances[idx].Weight()
if weight > 0 {
w.instances[cnt] = e.Instances[idx]
w.entries[cnt] = weight
w.weightSum += weight
cnt++
} else {
hlog.SystemLogger().Warnf("Invalid weight=%d on instance address=%s", weight, e.Instances[idx].Address())
}
}
w.instances = w.instances[:cnt]
return w
}
// Pick implements the Loadbalancer interface.
func (wb *weightedBalancer) Pick(e discovery.Result) discovery.Instance {
wi, ok := wb.cachedWeightInfo.Load(e.CacheKey)
if !ok {
wi, _, _ = wb.sfg.Do(e.CacheKey, func() (interface{}, error) {
return wb.calcWeightInfo(e), nil
})
wb.cachedWeightInfo.Store(e.CacheKey, wi)
}
w := wi.(*weightInfo)
if w.weightSum <= 0 {
return nil
}
weight := fastrand.Intn(w.weightSum)
for i := 0; i < len(w.instances); i++ {
weight -= w.entries[i]
if weight < 0 {
return w.instances[i]
}
}
return nil
}
// Rebalance implements the Loadbalancer interface.
func (wb *weightedBalancer) Rebalance(e discovery.Result) {
wb.cachedWeightInfo.Store(e.CacheKey, wb.calcWeightInfo(e))
}
// Delete implements the Loadbalancer interface.
func (wb *weightedBalancer) Delete(cacheKey string) {
wb.cachedWeightInfo.Delete(cacheKey)
}
func (wb *weightedBalancer) Name() string {
return "weight_random"
}