Golang 业务限流器

github地址 https://github.com/xiaowei520...

package rate
import (
 "math/rand"
 "sync"
 "sync/atomic"
 "time"
)
//使用cas 锁来实现、减少开销
//业务限流器
const (
 Normal = iota
 AbNormal
)
//标示, 可以是appId uid 唯一性的代表值
type Limit float64
type Limiter struct {
 limit Limit
 EventName string
 //cas
 done uint32
 //时间
 retryTime int
 //重试次数
 retryLen int
 //最大缓冲时间
 maxTime int64
 //最小缓冲时间
 minTime int64
 mu sync.Mutex
 // last is the last time the limiter's tokens field was updated
 last time.Time
 // lastEvent is the latest time of a rate-limited event (past or future)
 lastEvent time.Time
}
func NewLimiter(r Limit, n string) *Limiter {
 return &Limiter{
 limit: r,
 EventName: n,
 }
}
func DefaultLimiter(r Limit, n string) *Limiter {
 return &Limiter{
 limit: r,
 EventName: n,
 maxTime: 1000,
 minTime: 100,
 }
}
func (lim *Limiter) Allow() bool {
 //no limit rate
 if atomic.LoadUint32(&lim.done) == Normal {
 return true
 }
 //rand sleep, avoid conflict
 randTime := rand.Int63n(lim.maxTime-lim.minTime) + lim.minTime
 time.Sleep(time.Duration(randTime) * time.Millisecond)
 return false
}
//where use stop
func (lim *Limiter) Stop() bool {
 lim.mu.Lock()
 defer lim.mu.Unlock()
 if lim.done == Normal {
 defer atomic.StoreUint32(&lim.done, AbNormal)
 }
 return true
}
func (lim *Limiter) Recover() {
 if atomic.LoadUint32(&lim.done) == AbNormal {
 return
 }
 lim.mu.Lock()
 defer lim.mu.Unlock()
 if lim.done == AbNormal {
 defer atomic.StoreUint32(&lim.done, Normal)
 }
}

本文来自:Segmentfault

感谢作者:xiaowei520

查看原文:Golang 业务限流器

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