Rename util.config.Watcher -> util.config.Broadcaster.

Watch is a widely used term in the codebase, which doesn't capture
the key feature of this type: broadcasting a change to several
listeners.

pkg/proxy/config/config.go

@@ -73,7 +73,7 @@ type EndpointsConfigHandler interface {
 // It accepts "set", "add" and "remove" operations of endpoints via channels, and invokes registered handlers on change.
 type EndpointsConfig struct {
 	mux     *config.Mux
-	watcher *config.Watcher
+	bcaster *config.Broadcaster
 	store   *endpointsStore
 }
 
@@ -83,13 +83,13 @@ func NewEndpointsConfig() *EndpointsConfig {
 	updates := make(chan struct{})
 	store := &endpointsStore{updates: updates, endpoints: make(map[string]map[string]api.Endpoints)}
 	mux := config.NewMux(store)
-	watcher := config.NewWatcher()
-	go watchForUpdates(watcher, store, updates)
-	return &EndpointsConfig{mux, watcher, store}
+	bcaster := config.NewBroadcaster()
+	go watchForUpdates(bcaster, store, updates)
+	return &EndpointsConfig{mux, bcaster, store}
 }
 
 func (c *EndpointsConfig) RegisterHandler(handler EndpointsConfigHandler) {
-	c.watcher.Add(config.ListenerFunc(func(instance interface{}) {
+	c.bcaster.Add(config.ListenerFunc(func(instance interface{}) {
 		handler.OnUpdate(instance.([]api.Endpoints))
 	}))
 }
@@ -168,7 +168,7 @@ func (s *endpointsStore) MergedState() interface{} {
 // It accepts "set", "add" and "remove" operations of services via channels, and invokes registered handlers on change.
 type ServiceConfig struct {
 	mux     *config.Mux
-	watcher *config.Watcher
+	bcaster *config.Broadcaster
 	store   *serviceStore
 }
 
@@ -178,13 +178,13 @@ func NewServiceConfig() *ServiceConfig {
 	updates := make(chan struct{})
 	store := &serviceStore{updates: updates, services: make(map[string]map[string]api.Service)}
 	mux := config.NewMux(store)
-	watcher := config.NewWatcher()
-	go watchForUpdates(watcher, store, updates)
-	return &ServiceConfig{mux, watcher, store}
+	bcaster := config.NewBroadcaster()
+	go watchForUpdates(bcaster, store, updates)
+	return &ServiceConfig{mux, bcaster, store}
 }
 
 func (c *ServiceConfig) RegisterHandler(handler ServiceConfigHandler) {
-	c.watcher.Add(config.ListenerFunc(func(instance interface{}) {
+	c.bcaster.Add(config.ListenerFunc(func(instance interface{}) {
 		handler.OnUpdate(instance.([]api.Service))
 	}))
 }
@@ -259,10 +259,10 @@ func (s *serviceStore) MergedState() interface{} {
 	return services
 }
 
-// watchForUpdates invokes watcher.Notify() with the latest version of an object
+// watchForUpdates invokes bcaster.Notify() with the latest version of an object
 // when changes occur.
-func watchForUpdates(watcher *config.Watcher, accessor config.Accessor, updates <-chan struct{}) {
+func watchForUpdates(bcaster *config.Broadcaster, accessor config.Accessor, updates <-chan struct{}) {
 	for _ = range updates {
-		watcher.Notify(accessor.MergedState())
+		bcaster.Notify(accessor.MergedState())
 	}
 }

pkg/util/config/config.go

@@ -110,30 +110,30 @@ func (f ListenerFunc) OnUpdate(instance interface{}) {
 	f(instance)
 }
 
-type Watcher struct {
+type Broadcaster struct {
 	// Listeners for changes and their lock.
 	listenerLock sync.RWMutex
 	listeners    []Listener
 }
 
-// NewWatcher registers a set of listeners that support the Listener interface
-// and notify them on changes.
-func NewWatcher() *Watcher {
-	return &Watcher{}
+// NewBroadcaster registers a set of listeners that support the Listener interface
+// and notifies them all on changes.
+func NewBroadcaster() *Broadcaster {
+	return &Broadcaster{}
 }
 
 // Add registers listener to receive updates of changes.
-func (m *Watcher) Add(listener Listener) {
-	m.listenerLock.Lock()
-	defer m.listenerLock.Unlock()
-	m.listeners = append(m.listeners, listener)
+func (b *Broadcaster) Add(listener Listener) {
+	b.listenerLock.Lock()
+	defer b.listenerLock.Unlock()
+	b.listeners = append(b.listeners, listener)
 }
 
 // Notify notifies all listeners.
-func (m *Watcher) Notify(instance interface{}) {
-	m.listenerLock.RLock()
-	listeners := m.listeners
-	m.listenerLock.RUnlock()
+func (b *Broadcaster) Notify(instance interface{}) {
+	b.listenerLock.RLock()
+	listeners := b.listeners
+	b.listenerLock.RUnlock()
 	for _, listener := range listeners {
 		listener.OnUpdate(instance)
 	}

pkg/util/config/config_test.go

@@ -97,24 +97,24 @@ func TestSimultaneousMerge(t *testing.T) {
 	<-ch
 }
 
-func TestWatcher(t *testing.T) {
-	watch := NewWatcher()
-	watch.Notify(struct{}{})
+func TestBroadcaster(t *testing.T) {
+	b := NewBroadcaster()
+	b.Notify(struct{}{})
 
 	ch := make(chan bool, 2)
-	watch.Add(ListenerFunc(func(object interface{}) {
+	b.Add(ListenerFunc(func(object interface{}) {
 		if object != "test" {
 			t.Errorf("Expected %s, Got %s", "test", object)
 		}
 		ch <- true
 	}))
-	watch.Add(ListenerFunc(func(object interface{}) {
+	b.Add(ListenerFunc(func(object interface{}) {
 		if object != "test" {
 			t.Errorf("Expected %s, Got %s", "test", object)
 		}
 		ch <- true
 	}))
-	watch.Notify("test")
+	b.Notify("test")
 	<-ch
 	<-ch
 }