forked from p93542168/wheat-cache
86 lines
1.6 KiB
Go
86 lines
1.6 KiB
Go
package endpoint
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import (
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"hash/crc32"
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"sort"
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"strconv"
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"gitee.com/wheat-os/wheatCache/pkg/errorx"
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)
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type HashFunc func(data []byte) uint32
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// 实现 sort
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type UInt32Slice []uint32
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func (s UInt32Slice) Len() int {
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return len(s)
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}
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func (s UInt32Slice) Less(i, j int) bool {
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return s[i] < s[j]
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}
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func (s UInt32Slice) Swap(i, j int) {
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s[i], s[j] = s[j], s[i]
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}
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type HashEndpoint struct {
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hash HashFunc
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replicas int // 复制因子
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keys UInt32Slice
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hashMap map[uint32]string // taraget 隐射
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}
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func NewHashEndpoint(replicas int, fn HashFunc, target ...string) EndpointInterface {
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endpoint := &HashEndpoint{
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replicas: replicas,
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hash: fn,
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hashMap: make(map[uint32]string, len(target)),
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}
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if endpoint.hash == nil {
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endpoint.hash = crc32.ChecksumIEEE // 默认使用 CRC32 算法
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}
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endpoint.AddTarget(target...)
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return endpoint
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}
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func (h *HashEndpoint) IsEmpty() bool {
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return len(h.keys) == 0
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}
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func (h *HashEndpoint) AddTarget(targets ...string) {
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for _, tar := range targets {
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for i := 0; i < h.replicas; i++ {
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hash := h.hash([]byte(strconv.Itoa(i) + tar))
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h.keys = append(h.keys, hash)
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h.hashMap[hash] = tar
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}
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}
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// 虚拟值排序，方便查找
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sort.Sort(h.keys)
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}
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func (h *HashEndpoint) GetTargetAddr(str ...string) (string, error) {
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if h.IsEmpty() {
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return "", errorx.New("gateway not register transport")
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}
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if len(str) != 1 {
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return "", errorx.New("must give key")
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}
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hash := h.hash([]byte(str[0]))
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idx := sort.Search(len(h.keys), func(i int) bool { return h.keys[i] >= hash })
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if idx == len(h.keys) {
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return h.hashMap[h.keys[0]], nil
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}
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return h.hashMap[h.keys[idx]], nil
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}
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