Golang加权轮询负载均衡的实现 Golang加权轮询负载均衡的实现

实现加权轮询负载均衡思路
加权轮询负载均衡代码
测试代码

实现加权轮询负载均衡思路
代码实现一个加权负载均衡

Weight初始化时对节点约定的权重
currentWeight节点临时权重，每轮都会变化
effectiveWeight节点有效权重，默认与Weight相同
totalWeight所有节点有效权重之和：sum(effectiveWeight)

代码实现一个加权负载均衡

currentWeight = currentWeight+effecitveWeight
选中最大的 currentWeight 节点为选中节点
currentWeight = currentWeight-totalWeight(4+3+2=9)

【Golang加权轮询负载均衡的实现】所以我们能够在表格模拟运行情况：

请求次数	请求前currentWelght	选中的节点	请求后currentWelght
1	[serverA=4,serverB=3,serverC=2]	serverA	[serverA=-1,serverB=6,serverC=4]
2	[serverA=-1,serverB=6,serverC=4]	serverB	[serverA=3,serverB=0,serverC=6]
3	[serverA=3,serverB=0,serverC=6]	serverc	[serverA=7,serverB=3,serverC=-1]
4	[serverA=7,serverB=3,serverC=-1]	serverA	[serverA=2,serverB=6,serverC=1]
5	[serverA=2,serverB=6,serverC=1]	serverB	[serverA=6,serverB=0,serverC=3]
6	[serverA=6,serverB=0,serverC=3]	serverA	[serverA=1,serverB=3,serverC=5]
7	[serverA=1,serverB=3,serverC=5]	serverc	[serverA=5,serverB=6,serverC=-2]

加权轮询负载均衡代码

package load_balanceimport ( "errors" "strconv")type WeightRoundRobinBalance struct { curIndex int rss[]*WeightNode rsw[]int //观察主体 conf LoadBalanceConf}// 配置主题type LoadBalanceConf interface { GetConf() []string WatchConf() UpdateConf(conf []string)}type WeightNode struct { addrstring // 服务器地址 weightint //权重值 currentWeightint //节点当前权重 effectiveWeight int //有效权重}func (r *WeightRoundRobinBalance) Add(params ...string) error { if len(params) != 2 {return errors.New("param len need 2") } parInt, err := strconv.ParseInt(params[1], 10, 64) if err != nil {return err } node := &WeightNode{addr: params[0], weight: int(parInt)} node.effectiveWeight = node.weight r.rss = append(r.rss, node) return nil}func (r *WeightRoundRobinBalance) Next() string { total := 0 var best *WeightNode for i := 0; i < len(r.rss); i++ {w := r.rss[i]//step 1 统计所有有效权重之和total += w.effectiveWeight//step 2 变更节点临时权重为的节点临时权重+节点有效权重w.currentWeight += w.effectiveWeight//step 3 有效权重默认与权重相同，通讯异常时-1, 通讯成功+1，直到恢复到weight大小if w.effectiveWeight < w.weight {w.effectiveWeight++}//step 4 选择最大临时权重点节点if best == nil || w.currentWeight > best.currentWeight {best = w} } if best == nil {return "" } //step 5 变更临时权重为临时权重-有效权重之和 best.currentWeight -= total return best.addr}func (r *WeightRoundRobinBalance) Get(key string) (string, error) { return r.Next(), nil}func (r *WeightRoundRobinBalance) SetConf(conf LoadBalanceConf) { r.conf = conf}

测试代码

package load_balanceimport ( "fmt" "testing")func TestLB(t *testing.T) { rb := &WeightRoundRobinBalance{} rb.Add("127.0.0.1:2003", "4") //0 // rb.Add("127.0.0.1:2004", "3") //1 rb.Add("127.0.0.1:2005", "2") //2 fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next()) fmt.Println(rb.Next())}

测试结果

$ go test
127.0.0.1:2003
127.0.0.1:2005
127.0.0.1:2003
127.0.0.1:2003
127.0.0.1:2005
127.0.0.1:2003
127.0.0.1:2003
127.0.0.1:2005
127.0.0.1:2003
127.0.0.1:2003
127.0.0.1:2005
127.0.0.1:2003
127.0.0.1:2003
127.0.0.1:2005
PASS
okgateway/_test/demo0.080s
## 127.0.0.1:2003 为 127.0.0.1:2005 权重两倍。而从答应结果上看，符合要求