Add Clear to Meter and Timer

meter.go

@@ -8,6 +8,7 @@ import (
 // Meters count events to produce exponentially-weighted moving average rates
 // at one-, five-, and fifteen-minutes and a mean rate.
 type Meter interface {
+	Clear()
 	Count() int64
 	Mark(int64)
 	Rate1() float64
@@ -59,6 +60,11 @@ type MeterSnapshot struct {
 	rate1, rate5, rate15, rateMean float64
 }
 
+// Clear panics.
+func (m *MeterSnapshot) Clear() {
+	panic("Clear called on a MeterSnapshot")
+}
+
 // Count returns the count of events at the time the snapshot was taken.
 func (m *MeterSnapshot) Count() int64 { return m.count }
 
@@ -89,6 +95,9 @@ func (m *MeterSnapshot) Snapshot() Meter { return m }
 // NilMeter is a no-op Meter.
 type NilMeter struct{}
 
+// Clear is a no-op.
+func (NilMeter) Clear() {}
+
 // Count is a no-op.
 func (NilMeter) Count() int64 { return 0 }
 
@@ -128,6 +137,18 @@ func newStandardMeter() *StandardMeter {
 	}
 }
 
+// Clear resets the meter.
+func (m *StandardMeter) Clear() {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	m.snapshot = &MeterSnapshot{}
+	m.a1 = NewEWMA1()
+	m.a5 = NewEWMA5()
+	m.a15 = NewEWMA15()
+	m.startTime = time.Now()
+}
+
 // Count returns the number of events recorded.
 func (m *StandardMeter) Count() int64 {
 	m.lock.RLock()

timer.go

@@ -7,6 +7,7 @@ import (
 
 // Timers capture the duration and rate of events.
 type Timer interface {
+	Clear()
 	Count() int64
 	Max() int64
 	Mean() float64
@@ -74,6 +75,9 @@ type NilTimer struct {
 	m Meter
 }
 
+// Clear is a no-op.
+func (NilTimer) Clear() {}
+
 // Count is a no-op.
 func (NilTimer) Count() int64 { return 0 }
 
@@ -135,6 +139,14 @@ type StandardTimer struct {
 	mutex     sync.Mutex
 }
 
+// Clear resets the timer.
+func (t *StandardTimer) Clear() {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+	t.histogram.Clear()
+	t.meter.Clear()
+}
+
 // Count returns the number of events recorded.
 func (t *StandardTimer) Count() int64 {
 	return t.histogram.Count()
@@ -240,6 +252,11 @@ type TimerSnapshot struct {
 	meter     *MeterSnapshot
 }
 
+// Clear panics.
+func (*TimerSnapshot) Clear() {
+	panic("Clear called on a TimerSnapshot")
+}
+
 // Count returns the number of events recorded at the time the snapshot was
 // taken.
 func (t *TimerSnapshot) Count() int64 { return t.histogram.Count() }