attenuator

attenuator.go

@@ -0,0 +1,59 @@
+package goutil
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+type Attenuator struct {
+	sync.Mutex
+	memory *Memory
+}
+
+func NewAttenuator() *Attenuator {
+	return &Attenuator{
+		memory: NewMemory(),
+	}
+}
+
+func (a *Attenuator) Do(key string, fun func()) bool {
+	a.Lock()
+	defer a.Unlock()
+
+	val := a.memory.Get(key)
+	if val == nil {
+		go fun()
+		a.memory.Set(key, fmt.Sprintf("%d,1", time.Now().Unix()), time.Hour*time.Duration(24*365*100))
+		return true
+	}
+
+	fields := strings.Split(val.(string), ",")
+
+	timestamp, _ := strconv.ParseInt(fields[0], 10, 64)
+	count, _ := strconv.ParseInt(fields[0], 10, 64)
+
+	count += 1
+	nowTime := time.Now().Unix()
+	if nowTime-timestamp <= int64(math.Pow(2, float64(count)))*60 {
+		return false
+	}
+
+	go fun()
+	a.memory.Set(key, fmt.Sprintf("%d,%d", nowTime, count), time.Hour*time.Duration(24*365*100))
+	return true
+}
+
+func (a *Attenuator) Clear(key string) bool {
+	a.Lock()
+	defer a.Unlock()
+
+	if a.memory.IsExist(key) {
+		a.memory.Delete(key)
+		return true
+	}
+	return false
+}