golang实现权重轮询调度算法(Weighted Round-Robin Scheduling)

最近在看golang连接mysql数据库的例子(Go-MySQL-Driver),但是想到连接数据库肯定会有连接多从库的需求,而且每个从库的权重也会不一样,参考<<权重轮询调度算法(Weighted Round-Robin Scheduling) >>这篇文章写了一个golang版本的权重轮询调度算法,请大家指教,不多说了直接上代码:

 package main
 
 import (
 	"fmt"
 	"time"
 )
 
 var slaveDns = map[int]map[string]interface{}{
 	0: {"connectstring": "root@tcp(172.16.0.164:3306)/shiqu_tools?charset=utf8", "weight": 2},
 	1: {"connectstring": "root@tcp(172.16.0.165:3306)/shiqu_tools?charset=utf8", "weight": 4},
 	2: {"connectstring": "root@tcp(172.16.0.166:3306)/shiqu_tools?charset=utf8", "weight": 8},
 }
 
 var i int = -1 //表示上一次选择的服务器
 var cw int = 0 //表示当前调度的权值
 var gcd int = 2 //当前所有权重的最大公约数 比如 2,4,8 的最大公约数为:2
 
 func getDns() string {
 	for {
 		i = (i + 1) % len(slaveDns)
 		if i == 0 {
 			cw = cw - gcd
 			if cw <= 0 {
 				cw = getMaxWeight()
 				if cw == 0 {
 					return ""
 				}
 			}
 		}
 
 		if weight, _ := slaveDns[i]["weight"].(int); weight >= cw {
 			return slaveDns[i]["connectstring"].(string)
 		}
 	}
 }
 
 func getMaxWeight() int {
 	max := 0
 	for _, v := range slaveDns {
 		if weight, _ := v["weight"].(int); weight >= max {
 			max = weight
 		}
 	}
 
 	return max
 }
 
 func main() {
 
 	note := map[string]int{}
 
 	s_time := time.Now().Unix()
 
 	for i := 0; i < 100; i++ {
 		s := getDns()
 		fmt.Println(s)
 		if note[s] != 0 {
 			note[s]++
 		} else {
 			note[s] = 1
 		}
 	}
 
 	e_time := time.Now().Unix()
 
 	fmt.Println("total time: ", e_time-s_time)
 
 	fmt.Println("--------------------------------------------------")
 
 	for k, v := range note {
 		fmt.Println(k, " ", v)
 	}
 }

100次结果是:

[画像:6122A254-6586-473B-A741-7227782B3FB2.png]

本文来自:开源中国博客

感谢作者:Lancerio

查看原文:golang实现权重轮询调度算法(Weighted Round-Robin Scheduling)

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