package prometheus import ( "runtime" "testing" "time" dto "github.com/prometheus/client_model/go" ) func TestGoCollector(t *testing.T) { var ( c = NewGoCollector() ch = make(chan Metric) waitc = make(chan struct{}) closec = make(chan struct{}) old = -1 ) defer close(closec) go func() { c.Collect(ch) go func(c <-chan struct{}) { <-c }(closec) <-waitc c.Collect(ch) }() for { select { case metric := <-ch: switch m := metric.(type) { // Attention, this also catches Counter... case Gauge: pb := &dto.Metric{} m.Write(pb) if pb.GetGauge() == nil { continue } if old == -1 { old = int(pb.GetGauge().GetValue()) close(waitc) continue } if diff := int(pb.GetGauge().GetValue()) - old; diff != 1 { // TODO: This is flaky in highly concurrent situations. t.Errorf("want 1 new goroutine, got %d", diff) } // GoCollector performs two sends per call. // On line 27 we need to revceive the second send // to shutdown cleanly. <-ch return } case <-time.After(1 * time.Second): t.Fatalf("expected collect timed out") } } } func TestGCCollector(t *testing.T) { var ( c = NewGoCollector() ch = make(chan Metric) waitc = make(chan struct{}) closec = make(chan struct{}) oldGC uint64 oldPause float64 ) defer close(closec) go func() { c.Collect(ch) // force GC runtime.GC() <-waitc c.Collect(ch) }() first := true for { select { case metric := <-ch: switch m := metric.(type) { case *constSummary, *value: pb := &dto.Metric{} m.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(waitc) continue } if diff := *pb.GetSummary().SampleCount - oldGC; diff != 1 { t.Errorf("want 1 new garbage collection run, got %d", diff) } if diff := *pb.GetSummary().SampleSum - oldPause; diff <= 0 { t.Errorf("want moar pause, got %f", diff) } return } case <-time.After(1 * time.Second): t.Fatalf("expected collect timed out") } } }