Merge pull request #277 from ggaaooppeenngg/goCollector

goCollector: add thread count gauge in goCollector

prometheus/go_collector.go

@@ -8,7 +8,8 @@ import (
 )
 
 type goCollector struct {
-	goroutines Gauge
+	goroutinesDesc *Desc
+	threadsDesc    *Desc
 	gcDesc         *Desc
 
 	// metrics to describe and collect
@@ -19,11 +20,14 @@ type goCollector struct {
 // go process.
 func NewGoCollector() Collector {
 	return &goCollector{
-		goroutines: NewGauge(GaugeOpts{
-			Namespace: "go",
-			Name:      "goroutines",
-			Help:      "Number of goroutines that currently exist.",
-		}),
+		goroutinesDesc: NewDesc(
+			"go_goroutines",
+			"Number of goroutines that currently exist.",
+			nil, nil),
+		threadsDesc: NewDesc(
+			"go_threads",
+			"Number of OS threads created",
+			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
 			"A summary of the GC invocation durations.",
@@ -224,9 +228,9 @@ func memstatNamespace(s string) string {
 
 // Describe returns all descriptions of the collector.
 func (c *goCollector) Describe(ch chan<- *Desc) {
-	ch <- c.goroutines.Desc()
+	ch <- c.goroutinesDesc
+	ch <- c.threadsDesc
 	ch <- c.gcDesc
-
 	for _, i := range c.metrics {
 		ch <- i.desc
 	}
@@ -234,8 +238,9 @@ func (c *goCollector) Describe(ch chan<- *Desc) {
 
 // Collect returns the current state of all metrics of the collector.
 func (c *goCollector) Collect(ch chan<- Metric) {
-	c.goroutines.Set(float64(runtime.NumGoroutine()))
-	ch <- c.goroutines
+	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
+	n, _ := runtime.ThreadCreateProfile(nil)
+	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
 
 	var stats debug.GCStats
 	stats.PauseQuantiles = make([]time.Duration, 5)

prometheus/go_collector_test.go

@@ -29,10 +29,13 @@ func TestGoCollector(t *testing.T) {
 
 	for {
 		select {
-		case metric := <-ch:
-			switch m := metric.(type) {
-			// Attention, this also catches Counter...
-			case Gauge:
+		case m := <-ch:
+			// 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 {
@@ -50,12 +53,12 @@ func TestGoCollector(t *testing.T) {
 				t.Errorf("want 1 new goroutine, got %d", diff)
 			}
 
-				// GoCollector performs two sends per call.
+			// GoCollector performs three sends per call.
 			// On line 27 we need to receive the second send
 			// to shut down cleanly.
 			<-ch
+			<-ch
 			return
-			}
 		case <-time.After(1 * time.Second):
 			t.Fatalf("expected collect timed out")
 		}