Golang实现按比例切分流量的示例详解

import (  "fmt"  "math/rand"  "sync/atomic")
type TrafficControl struct {  
    source     []int  
    queryCount uint32  
    base       int  
    ratio      int
}
func NewTrafficControl(base int, ratio int) *TrafficControl {  
    source := make([]int, base)  
    for i := 0; i < base; i++ {    
        source[i] = i  
    }
    rand.Shuffle(base, func(i, j int) {    
        source[i], source[j] = source[j], source[i]  
    })
    return &TrafficControl{    
        source: source,    
        base:   base,    
        ratio:  ratio,  
    }
}
func (t *TrafficControl) Allow() bool {  
    rate := t.source[int(atomic.AddUint32(&t.queryCount, 1))%t.base]  
    if rate < t.ratio {    
        return true  
    } else {    
        return false  
    }
}

func main() {  
    trafficCtl := NewTrafficControl(10, 6)  
    cnt := 100  
    serviceAQueryCnt := 0  
    serviceBQueryCnt := 0  
    for cnt > 0 {    
        if trafficCtl.Allow() {      
            serviceAQueryCnt++    
        } else {      
            serviceBQueryCnt++    
        }    
        cnt--  
    }
    fmt.Printf("service A query count: %v, service B query count %v", serviceAQueryCnt, serviceBQueryCnt)
}