feat(transport): add hash transport

gateway/transport/define.go

@@ -0,0 +1,7 @@
+package transport
+
+type TransPortInterface interface {
+	GetTargetAddr(...string) (string, error)
+	IsEmpty() bool
+	AddTarget(targets ...string)
+}

gateway/transport/hash.go

@@ -0,0 +1,85 @@
+package transport
+
+import (
+	"hash/crc32"
+	"sort"
+	"strconv"
+
+	"gitee.com/timedb/wheatCache/pkg/errorx"
+)
+
+type HashFunc func(data []byte) uint32
+
+// 实现 sort
+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 HashTransport struct {
+	hash     HashFunc
+	replicas int // 复制因子
+	keys     UInt32Slice
+	hashMap  map[uint32]string // taraget 隐射
+}
+
+func NewHashTransport(replicas int, fn HashFunc, target ...string) TransPortInterface {
+	transport := &HashTransport{
+		replicas: replicas,
+		hash:     fn,
+		hashMap:  make(map[uint32]string, len(target)),
+	}
+
+	if transport.hash == nil {
+		transport.hash = crc32.ChecksumIEEE // 默认使用 CRC32 算法
+	}
+
+	transport.AddTarget(target...)
+
+	return transport
+}
+
+func (h *HashTransport) IsEmpty() bool {
+	return len(h.keys) == 0
+}
+
+func (h *HashTransport) AddTarget(targets ...string) {
+	for _, tar := range targets {
+
+		for i := 0; i < h.replicas; i++ {
+			hash := h.hash([]byte(strconv.Itoa(i) + tar))
+			h.keys = append(h.keys, hash)
+			h.hashMap[hash] = tar
+		}
+	}
+
+	// 虚拟值排序，方便查找
+	sort.Sort(h.keys)
+}
+
+func (h *HashTransport) GetTargetAddr(str ...string) (string, error) {
+	if h.IsEmpty() {
+		return "", errorx.New("gateway not register transport")
+	}
+
+	if len(str) != 1 {
+		return "", errorx.New("must give key")
+
+	}
+	hash := h.hash([]byte(str[0]))
+	idx := sort.Search(len(h.keys), func(i int) bool { return h.keys[i] >= hash })
+	if idx == len(h.keys) {
+		return h.hashMap[h.keys[0]], nil
+	}
+
+	return h.hashMap[h.keys[idx]], nil
+}