1. adding statistics reporting

2. refactor version to util package

go/stats/duration_counter.go

@@ -0,0 +1,83 @@
+package stats
+
+import (
+	"time"
+)
+
+type TimedValue struct {
+	t   time.Time
+	val int64
+}
+
+func NewTimedValue(t time.Time, val int64) *TimedValue {
+	return &TimedValue{t: t, val: val}
+}
+
+type RoundRobinCounter struct {
+	LastIndex int
+	Values    []int64
+	Counts    []int64
+}
+
+func NewRoundRobinCounter(slots int) *RoundRobinCounter {
+	return &RoundRobinCounter{LastIndex: -1, Values: make([]int64, slots), Counts: make([]int64, slots)}
+}
+func (rrc *RoundRobinCounter) Add(index int, val int64) {
+	for rrc.LastIndex != index {
+		rrc.LastIndex++
+		if rrc.LastIndex >= len(rrc.Values) {
+			if index >= len(rrc.Values) {
+				break //just avoid endless loop
+			}
+			rrc.LastIndex = 0
+		}
+		rrc.Values[rrc.LastIndex] = 0
+		rrc.Counts[rrc.LastIndex] = 0
+	}
+	rrc.Values[index] += val
+	rrc.Counts[index]++
+}
+func (rrc *RoundRobinCounter) Max() (max int64) {
+	for _, val := range rrc.Values {
+		if max < val {
+			max = val
+		}
+	}
+	return
+}
+func (rrc *RoundRobinCounter) Count() (cnt int64) {
+	for _, c := range rrc.Counts {
+		cnt += c
+	}
+	return
+}
+func (rrc *RoundRobinCounter) Sum() (sum int64) {
+	for _, val := range rrc.Values {
+		sum += val
+	}
+	return
+}
+
+type DurationCounter struct {
+	MinuteCounter *RoundRobinCounter
+	HourCounter   *RoundRobinCounter
+	DayCounter    *RoundRobinCounter
+	WeekCounter   *RoundRobinCounter
+}
+
+func NewDurationCounter() *DurationCounter {
+	return &DurationCounter{
+		MinuteCounter: NewRoundRobinCounter(60),
+		HourCounter:   NewRoundRobinCounter(60),
+		DayCounter:    NewRoundRobinCounter(24),
+		WeekCounter:   NewRoundRobinCounter(7),
+	}
+}
+
+// Add is for cumulative counts
+func (sc *DurationCounter) Add(tv *TimedValue) {
+	sc.MinuteCounter.Add(tv.t.Second(), tv.val)
+	sc.HourCounter.Add(tv.t.Minute(), tv.val)
+	sc.DayCounter.Add(tv.t.Hour(), tv.val)
+	sc.WeekCounter.Add(int(tv.t.Weekday()), tv.val)
+}