chanotify should use interface{} keys

Fixes #79.

Signed-off-by: Burcu Dogan <jbd@golang.org>

chanotify/chanotify.go

@@ -11,41 +11,41 @@ import (
 // notification from Notifier, close doesn't spawn anything and removes channel
 // from Notifier.
 type Notifier struct {
-	c chan string
+	c chan interface{}
 
 	m      sync.Mutex // guards doneCh
-	doneCh map[string]chan struct{}
+	doneCh map[interface{}]chan struct{}
 }
 
 // New returns a new *Notifier.
 func New() *Notifier {
 	s := &Notifier{
-		c:      make(chan string),
+		c:      make(chan interface{}),
-		doneCh: make(map[string]chan struct{}),
+		doneCh: make(map[interface{}]chan struct{}),
 	}
 	return s
 }
 
 // Chan returns channel on which client listen for notifications.
 // IDs of notifications is sent to the returned channel.
-func (n *Notifier) Chan() <-chan string {
+func (n *Notifier) Chan() <-chan interface{} {
 	return n.c
 }
 
-func (n *Notifier) killWorker(id string, done chan struct{}) {
+func (n *Notifier) killWorker(id interface{}, done chan struct{}) {
 	n.m.Lock()
 	delete(n.doneCh, id)
 	n.m.Unlock()
 }
 
 // Add adds new notification channel to Notifier.
-func (n *Notifier) Add(ch <-chan struct{}, id string) {
+func (n *Notifier) Add(id interface{}, ch <-chan struct{}) {
 	done := make(chan struct{})
 	n.m.Lock()
 	n.doneCh[id] = done
 	n.m.Unlock()
 
-	go func(ch <-chan struct{}, id string, done chan struct{}) {
+	go func(ch <-chan struct{}, id interface{}, done chan struct{}) {
 		for {
 			select {
 			case _, ok := <-ch:

chanotify/chanotify_test.go

@@ -11,8 +11,8 @@ func TestNotifier(t *testing.T) {
 	s := New()
 	ch1 := make(chan struct{}, 1)
 	ch2 := make(chan struct{}, 1)
-	s.Add(ch1, "1")
+	s.Add("1", ch1)
-	s.Add(ch2, "2")
+	s.Add("2", ch2)
 	s.m.Lock()
 	if len(s.doneCh) != 2 {
 		t.Fatalf("expected 2 channels, got %d", len(s.doneCh))
@@ -20,12 +20,12 @@ func TestNotifier(t *testing.T) {
 	s.m.Unlock()
 	ch1 <- struct{}{}
 	id1 := <-s.Chan()
-	if id1 != "1" {
+	if id1.(string) != "1" {
 		t.Fatalf("1 should be spawned, got %s", id1)
 	}
 	ch2 <- struct{}{}
 	id2 := <-s.Chan()
-	if id2 != "2" {
+	if id2.(string) != "2" {
 		t.Fatalf("2 should be spawned, got %s", id2)
 	}
 	close(ch1)
@@ -43,10 +43,10 @@ func TestConcurrentNotifier(t *testing.T) {
 	var chs []chan struct{}
 	for i := 0; i < 8; i++ {
 		ch := make(chan struct{}, 2)
-		s.Add(ch, strconv.Itoa(i))
+		s.Add(strconv.Itoa(i), ch)
 		chs = append(chs, ch)
 	}
-	testCounter := make(map[string]int)
+	testCounter := make(map[interface{}]int)
 	done := make(chan struct{})
 	go func() {
 		for id := range s.Chan() {
@@ -85,7 +85,7 @@ func TestAddToBlocked(t *testing.T) {
 	go func() {
 		// give some time to start first select
 		time.Sleep(1 * time.Second)
-		s.Add(ch, "1")
+		s.Add("1", ch)
 		ch <- struct{}{}
 	}()
 	val := <-s.Chan()

supervisor/supervisor.go

@@ -50,7 +50,7 @@ func New(id, stateDir string, tasks chan *StartTask, oom bool) (*Supervisor, err
 		go func() {
 			for id := range s.notifier.Chan() {
 				e := NewEvent(OOMEventType)
-				e.ID = id
+				e.ID = id.(string)
 				s.SendEvent(e)
 			}
 		}()

supervisor/worker.go

@@ -74,7 +74,7 @@ func (w *worker) Start() {
 			if err != nil {
 				logrus.WithField("error", err).Error("containerd: notify OOM events")
 			} else {
-				w.s.notifier.Add(n, t.Container.ID())
+				w.s.notifier.Add(t.Container.ID(), n)
 			}
 		}
 		ContainerStartTimer.UpdateSince(started)