Golang实现四种负载均衡的算法(随机,轮询等)

Bea ·

更新时间:2024-11-14

· 1555 次阅读

随机负载

随机挑选目标服务器


package load_balance
import (
 "errors"
 "math/rand"
)
//随机负载均衡
type RandomBalance struct {
 curIndex int
 rss []string
}
func (r *RandomBalance) Add(params ...string) error {
 if len(params) == 0 {
  return errors.New("params len 1 at least")
 }
 addr := params[0]
 r.rss = append(r.rss, addr)
 return nil
}
func (r *RandomBalance) Next() string {
 if len(r.rss) == 0 {
  return ""
 }
 r.curIndex = rand.Intn(len(r.rss))
 return r.rss[r.curIndex]
}
func (r *RandomBalance) Get(string) (string, error) {
 return r.Next(), nil
}

轮询负载

服务器依次轮询


package load_balance
import "errors"
//轮询负载均衡
type RoundRobinBalance struct {
 curIndex int
 rss      []string
}
func (r *RoundRobinBalance) Add(params ...string) error {
 if len(params) == 0 {
  return errors.New("params len 1 at least")
 }
 addr := params[0]
 r.rss = append(r.rss, addr)
 return nil
}
func (r *RoundRobinBalance) Next() string {
 if len(r.rss) == 0 {
  return ""
 }
 lens := len(r.rss)
 if r.curIndex >= lens {
  r.curIndex = 0
 }
 curAddr := r.rss[r.curIndex]
 r.curIndex = (r.curIndex + 1) % lens
 return curAddr
}
func (r *RoundRobinBalance) Get(string) (string, error) {
 return r.Next(), nil
}

加权轮询负载

给目标设置访问权重，按照权重轮询


package load_balance
import (
 "errors"
 "strconv"
)
type WeightRoundRobinBalance struct {
 curIndex int
 rss      []*WeightNode
 rsw      []int
}
type WeightNode struct {
 addr            string
 Weight          int //初始化时对节点约定的权重
 currentWeight   int //节点临时权重，每轮都会变化
 effectiveWeight int //有效权重, 默认与weight相同 , totalWeight = sum(effectiveWeight)  //出现故障就-1
}
//1, currentWeight = currentWeight + effectiveWeight
//2, 选中最大的currentWeight节点为选中节点
//3, currentWeight = currentWeight - totalWeight
func (r *WeightRoundRobinBalance) Add(params ...string) error {
 if len(params) != 2 {
  return errors.New("params 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 {
 var best *WeightNode
 total := 0
 for i := 0; i < len(r.rss); i++ {
  w := r.rss[i]
  //1 计算所有有效权重
  total += w.effectiveWeight
  //2 修改当前节点临时权重
  w.currentWeight += w.effectiveWeight
  //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++
  }
  //4 选中最大临时权重节点
  if best == nil || w.currentWeight > best.currentWeight {
   best = w
  }
 }
 if best == nil {
  return ""
 }
 //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(string) (string, error) {
 return r.Next(), nil
}
func (r *WeightRoundRobinBalance) Update()  {
}

一致性hash

请求固定的URL访问指定的IP


package load_balance
import (
 "errors"
 "hash/crc32"
 "sort"
 "strconv"
 "sync"
)
//1 单调性（唯一） 2平衡性 (数据 目标元素均衡) 3分散性(散列)
type Hash func(data []byte) uint32
type UInt32Slice []uint32
func (s UInt32Slice) Len() int {
 return len(s)
}
func (s UInt32Slice) Less(i, j int) bool {
 return s[i] < s[j]
}
func (s UInt32Slice) Swap(i, j int) {
 s[i], s[j] = s[j], s[i]
}
type ConsistentHashBalance struct {
 mux      sync.RWMutex
 hash     Hash
 replicas int               //复制因子
 keys     UInt32Slice       //已排序的节点hash切片
 hashMap  map[uint32]string //节点哈希和key的map, 键是hash值，值是节点key
}
func NewConsistentHashBalance(replicas int, fn Hash) *ConsistentHashBalance {
 m := &ConsistentHashBalance{
  replicas: replicas,
  hash:     fn,
  hashMap:  make(map[uint32]string),
 }
 if m.hash == nil {
  //最多32位，保证是一个2^32-1环
  m.hash = crc32.ChecksumIEEE
 }
 return m
}
func (c *ConsistentHashBalance) IsEmpty() bool {
 return len(c.keys) == 0
}
// Add 方法用来添加缓存节点，参数为节点key，比如使用IP
func (c *ConsistentHashBalance) Add(params ...string) error {
 if len(params) == 0 {
  return errors.New("param len 1 at least")
 }
 addr := params[0]
 c.mux.Lock()
 defer c.mux.Unlock()
 // 结合复制因子计算所有虚拟节点的hash值，并存入m.keys中，同时在m.hashMap中保存哈希值和key的映射
 for i := 0; i < c.replicas; i++ {
  hash := c.hash([]byte(strconv.Itoa(i) + addr))
  c.keys = append(c.keys, hash)
  c.hashMap[hash] = addr
 }
 // 对所有虚拟节点的哈希值进行排序，方便之后进行二分查找
 sort.Sort(c.keys)
 return nil
}
// Get 方法根据给定的对象获取最靠近它的那个节点
func (c *ConsistentHashBalance) Get(key string) (string, error) {
 if c.IsEmpty() {
  return "", errors.New("node is empty")
 }
 hash := c.hash([]byte(key))
 // 通过二分查找获取最优节点，第一个"服务器hash"值大于"数据hash"值的就是最优"服务器节点"
 idx := sort.Search(len(c.keys), func(i int) bool { return c.keys[i] >= hash })
 // 如果查找结果 大于 服务器节点哈希数组的最大索引，表示此时该对象哈希值位于最后一个节点之后，那么放入第一个节点中
 if idx == len(c.keys) {
  idx = 0
 }
 c.mux.RLock()
 defer c.mux.RUnlock()
 return c.hashMap[c.keys[idx]], nil
}

封装

定义LoadBalance接口


package load_balance
type LoadBalance interface {
 Add(...string) error
 Get(string)(string, error)
}

工厂方法


package load_balance
type LbType int
const (
 LbRandom LbType = iota
 LbRoundRobin
 LbWeightRoundRobin
 LbConsistentHash
)
func LoadBalanceFactory(lbType LbType) LoadBalance {
 switch lbType {
 case LbRandom:
  return &RandomBalance{}
 case LbConsistentHash:
  return NewConsistentHashBalance(10, nil)
 case LbRoundRobin:
  return &RoundRobinBalance{}
 case LbWeightRoundRobin:
  return &WeightRoundRobinBalance{}
 default:
  return &RandomBalance{}
 }
}

到此这篇关于Golang实现四种负载均衡的算法(随机,轮询等)的文章就介绍到这了,更多相关Golang 负载均衡内容请搜索软件开发网以前的文章或继续浏览下面的相关文章希望大家以后多多支持软件开发网！

负载均衡算法 golang

1024 个赞