Function TestGoCollectorGC

prometheus/go_collector_test.go:91–156

(t *testing.T)

}

func TestGoCollectorGC(t *testing.T) {
	var (
		c               = NewGoCollector()
		metricCh        = make(chan Metric)
		waitCh          = make(chan struct{})
		endCollectionCh = make(chan struct{})
		oldGC           uint64
		oldPause        float64
	)

	go func() {
		c.Collect(metricCh)
		// force GC
		runtime.GC()
		<-waitCh
		c.Collect(metricCh)
		close(endCollectionCh)
	}()

	defer func() {
		// Drain the collect channel to prevent goroutine leak.
		for {
			select {
			case <-metricCh:
			case <-endCollectionCh:
				return
			}
		}
	}()

	first := true
	for {
		select {
		case metric := <-metricCh:
			pb := &dto.Metric{}
			metric.Write(pb)
			if pb.GetSummary() == nil {
				continue
			}
			if len(pb.GetSummary().Quantile) != 5 {
				t.Errorf("expected 4 buckets, got %d", len(pb.GetSummary().Quantile))
			}
			for idx, want := range []float64{0.0, 0.25, 0.5, 0.75, 1.0} {
				if *pb.GetSummary().Quantile[idx].Quantile != want {
					t.Errorf("bucket #%d is off, got %f, want %f", idx, *pb.GetSummary().Quantile[idx].Quantile, want)
				}
			}
			if first {
				first = false
				oldGC = *pb.GetSummary().SampleCount
				oldPause = *pb.GetSummary().SampleSum
				close(waitCh)
				continue
			}
			if diff := *pb.GetSummary().SampleCount - oldGC; diff < 1 {
				t.Errorf("want at least 1 new garbage collection run, got %d", diff)
			}
			if diff := *pb.GetSummary().SampleSum - oldPause; diff <= 0 {