feat: cache add single-flight and timing-wheel.

pkg/common/localcache/target.go

@@ -0,0 +1,59 @@
+package localcache
+
+import (
+	"fmt"
+	"sync/atomic"
+)
+
+type Target interface {
+	IncrGetHit()
+	IncrGetSuccess()
+	IncrGetFailed()
+
+	IncrDelHit()
+	IncrDelNotFound()
+}
+
+type cacheTarget struct {
+	getHit      int64
+	getSuccess  int64
+	getFailed   int64
+	delHit      int64
+	delNotFound int64
+}
+
+func (r *cacheTarget) IncrGetHit() {
+	atomic.AddInt64(&r.getHit, 1)
+}
+
+func (r *cacheTarget) IncrGetSuccess() {
+	atomic.AddInt64(&r.getSuccess, 1)
+}
+
+func (r *cacheTarget) IncrGetFailed() {
+	atomic.AddInt64(&r.getFailed, 1)
+}
+
+func (r *cacheTarget) IncrDelHit() {
+	atomic.AddInt64(&r.delHit, 1)
+}
+
+func (r *cacheTarget) IncrDelNotFound() {
+	atomic.AddInt64(&r.delNotFound, 1)
+}
+
+func (r *cacheTarget) String() string {
+	return fmt.Sprintf("getHit: %d, getSuccess: %d, getFailed: %d, delHit: %d, delNotFound: %d", r.getHit, r.getSuccess, r.getFailed, r.delHit, r.delNotFound)
+}
+
+type emptyTarget struct{}
+
+func (e emptyTarget) IncrGetHit() {}
+
+func (e emptyTarget) IncrGetSuccess() {}
+
+func (e emptyTarget) IncrGetFailed() {}
+
+func (e emptyTarget) IncrDelHit() {}
+
+func (e emptyTarget) IncrDelNotFound() {}