Add basic stats

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

containerd/daemon.go

@@ -36,6 +36,11 @@ var DaemonCommand = cli.Command{
 			l := log.New(os.Stdout, "[containerd] ", log.LstdFlags)
 			goRoutineCounter := metrics.NewGauge()
 			metrics.DefaultRegistry.Register("goroutines", goRoutineCounter)
+			for name, m := range containerd.Metrics() {
+				if err := metrics.DefaultRegistry.Register(name, m); err != nil {
+					logrus.Fatal(err)
+				}
+			}
 			go func() {
 				for range time.Tick(30 * time.Second) {
 					goRoutineCounter.Update(int64(runtime.NumGoroutine()))

stats.go

@@ -0,0 +1,15 @@
+package containerd
+
+import "github.com/rcrowley/go-metrics"
+
+var (
+	ContainerStartTimer = metrics.NewTimer()
+	ContainersCounter   = metrics.NewCounter()
+)
+
+func Metrics() map[string]interface{} {
+	return map[string]interface{}{
+		"container-start-time": ContainerStartTimer,
+		"containers":           ContainersCounter,
+	}
+}

supervisor.go

@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"sync"
+	"time"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/opencontainers/runc/libcontainer"
@@ -107,6 +108,7 @@ func (s *Supervisor) Start(events chan *Event) error {
 					continue
 				}
 				s.containers[e.ID] = container
+				ContainersCounter.Inc(1)
 				s.tasks <- &startTask{
 					err:       e.Err,
 					container: container,
@@ -117,6 +119,7 @@ func (s *Supervisor) Start(events chan *Event) error {
 					if err := s.deleteContainer(container); err != nil {
 						logrus.WithField("error", err).Error("containerd: deleting container")
 					}
+					ContainersCounter.Dec(1)
 				}
 			case GetContainerEventType:
 				for _, c := range s.containers {
@@ -222,6 +225,7 @@ type startTask struct {
 func (s *Supervisor) startContainerWorker(tasks chan *startTask) {
 	defer s.workerGroup.Done()
 	for t := range tasks {
+		started := time.Now()
 		if err := t.container.Start(); err != nil {
 			e := NewEvent(StartContainerEventType)
 			e.ID = t.container.ID()
@@ -229,6 +233,7 @@ func (s *Supervisor) startContainerWorker(tasks chan *startTask) {
 			t.err <- err
 			continue
 		}
+		ContainerStartTimer.UpdateSince(started)
 		t.err <- nil
 	}
 }