104 lines
2.2 KiB
Go
104 lines
2.2 KiB
Go
// Package consistent_hash...
|
|
//
|
|
// Description : consistent_hash...
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 2021-11-21 4:57 下午
|
|
package consistent_hash
|
|
|
|
import (
|
|
"sort"
|
|
"strconv"
|
|
"sync"
|
|
)
|
|
|
|
// New 获取实例
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 5:03 下午 2021/11/21
|
|
func New(replicas int, fn HashFunc) *Consistent {
|
|
if nil == fn {
|
|
fn = DefaultHashFunc
|
|
}
|
|
return &Consistent{
|
|
hashFunc: fn,
|
|
replicas: replicas,
|
|
keys: make([]int, 0),
|
|
hashMap: make(map[int]string),
|
|
lock: &sync.RWMutex{},
|
|
}
|
|
}
|
|
|
|
// Consistent ...
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 5:00 下午 2021/11/21
|
|
type Consistent struct {
|
|
hashFunc HashFunc // 哈希函数
|
|
replicas int // 虚拟的数量
|
|
keys []int // 哈希环
|
|
hashMap map[int]string // 虚拟节点与真实节点的映射表
|
|
lock *sync.RWMutex // 锁
|
|
}
|
|
|
|
// Add 添加节点
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 5:10 下午 2021/11/21
|
|
func (c *Consistent) Add(keyList ...string) {
|
|
c.lock.Lock()
|
|
defer c.lock.Unlock()
|
|
for _, key := range keyList {
|
|
for i := 0; i < c.replicas; i++ {
|
|
hash := int(c.hashFunc([]byte(strconv.Itoa(i) + key)))
|
|
c.keys = append(c.keys, hash)
|
|
c.hashMap[hash] = key
|
|
}
|
|
}
|
|
// 哈希值排序
|
|
sort.Ints(c.keys)
|
|
}
|
|
|
|
// Get 获取节点
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 5:16 下午 2021/11/21
|
|
func (c *Consistent) Get(key string) string {
|
|
c.lock.RLock()
|
|
defer c.lock.Unlock()
|
|
if len(c.keys) == 0 {
|
|
return ""
|
|
}
|
|
hash := int(c.hashFunc([]byte(key)))
|
|
// 查找节点索引
|
|
idx := sort.Search(len(c.keys), func(i int) bool {
|
|
return c.keys[i] >= hash
|
|
})
|
|
return c.hashMap[c.keys[idx%len(c.keys)]]
|
|
}
|
|
|
|
// Delete 删除一个节点,本质逻辑 : 重建哈希环
|
|
//
|
|
// Author : go_developer@163.com<白茶清欢>
|
|
//
|
|
// Date : 5:35 下午 2021/11/21
|
|
func (c *Consistent) Delete(key string) {
|
|
c.lock.Lock()
|
|
defer c.lock.Unlock()
|
|
tmpKeyList := make([]string, 0)
|
|
for _, k := range c.hashMap {
|
|
if k == key {
|
|
continue
|
|
}
|
|
tmpKeyList = append(tmpKeyList, k)
|
|
}
|
|
c.hashMap = make(map[int]string)
|
|
c.keys = make([]int, 0)
|
|
c.Add(tmpKeyList...)
|
|
}
|