set timestamp by default. This behavior cannot be changed by users

container/statssum.go

@@ -23,12 +23,13 @@ import (
 )
 
 type statsSummaryContainerHandlerWrapper struct {
-	handler        ContainerHandler
-	currentSummary *info.ContainerStatsPercentiles
-	prevStats      *info.ContainerStats
-	numStats       uint64
-	sampler        sampling.Sampler
-	lock           sync.Mutex
+	handler          ContainerHandler
+	currentSummary   *info.ContainerStatsPercentiles
+	prevStats        *info.ContainerStats
+	numStats         uint64
+	sampler          sampling.Sampler
+	dontSetTimestamp bool
+	lock             sync.Mutex
 }
 
 func (self *statsSummaryContainerHandlerWrapper) GetSpec() (*info.ContainerSpec, error) {
@@ -65,8 +66,9 @@ func (self *statsSummaryContainerHandlerWrapper) GetStats() (*info.ContainerStat
 	if stats == nil {
 		return nil, nil
 	}
-	// Only update timestamp if it is zero.
-	if stats.Timestamp.IsZero() {
+	// update timestamp if it is required. This feature is for testibility.
+	// In some test, we want the underlying handler to set timestamp.
+	if !self.dontSetTimestamp {
 		stats.Timestamp = time.Now()
 	}
 	self.lock.Lock()

container/statssum_test.go

@@ -164,6 +164,13 @@ func TestSampleCpuUsage(t *testing.T) {
 		t.Error(err)
 	}
 
+	// we want to set our own time.
+	if w, ok := handler.(*statsSummaryContainerHandlerWrapper); ok {
+		w.dontSetTimestamp = true
+	} else {
+		t.Fatal("handler is not an instance of statsSummaryContainerHandlerWrapper")
+	}
+
 	// request stats/obervation N+1 times, so that there will be N samples
 	for i := 0; i < N+1; i++ {
 		_, err = handler.GetStats()