Function TestGoCollectorGoroutines

prometheus/go_collector_test.go:24–89

(t *testing.T)

)

func TestGoCollectorGoroutines(t *testing.T) {
	var (
		c               = NewGoCollector()
		metricCh        = make(chan Metric)
		waitCh          = make(chan struct{})
		endGoroutineCh  = make(chan struct{})
		endCollectionCh = make(chan struct{})
		old             = -1
	)
	defer func() {
		close(endGoroutineCh)
		// Drain the collect channel to prevent goroutine leak.
		for {
			select {
			case <-metricCh:
			case <-endCollectionCh:
				return
			}
		}
	}()

	go func() {
		c.Collect(metricCh)
		for i := 1; i <= 10; i++ {
			// Start 10 goroutines to be sure we'll detect an
			// increase even if unrelated goroutines happen to
			// terminate during this test.
			go func(c <-chan struct{}) {
				<-c
			}(endGoroutineCh)
		}
		<-waitCh
		c.Collect(metricCh)
		close(endCollectionCh)
	}()

	for {
		select {
		case m := <-metricCh:
			// m can be Gauge or Counter,
			// currently just test the go_goroutines Gauge
			// and ignore others.
			if m.Desc().fqName != "go_goroutines" {
				continue
			}
			pb := &dto.Metric{}
			m.Write(pb)
			if pb.GetGauge() == nil {
				continue
			}

			if old == -1 {
				old = int(pb.GetGauge().GetValue())
				close(waitCh)
				continue
			}

			if diff := old - int(pb.GetGauge().GetValue()); diff > -1 {