remove rq

core/discov/subscriber.go

@@ -36,6 +36,10 @@ func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscrib
 	return sub, nil
 }
 
+func (s *Subscriber) AddListener(listener func()) {
+	s.items.addListener(listener)
+}
+
 func (s *Subscriber) Values() []string {
 	return s.items.getValues()
 }
@@ -54,6 +58,7 @@ type container struct {
 	mapping   map[string]string
 	snapshot  atomic.Value
 	dirty     *syncx.AtomicBool
+	listeners []func()
 	lock      sync.Mutex
 }
 
@@ -68,10 +73,12 @@ func newContainer(exclusive bool) *container {
 
 func (c *container) OnAdd(kv internal.KV) {
 	c.addKv(kv.Key, kv.Val)
+	c.notifyChange()
 }
 
 func (c *container) OnDelete(kv internal.KV) {
 	c.removeKey(kv.Key)
+	c.notifyChange()
 }
 
 // addKv adds the kv, returns if there are already other keys associate with the value
@@ -98,6 +105,12 @@ func (c *container) addKv(key, value string) ([]string, bool) {
 	}
 }
 
+func (c *container) addListener(listener func()) {
+	c.lock.Lock()
+	c.listeners = append(c.listeners, listener)
+	c.lock.Unlock()
+}
+
 func (c *container) doRemoveKey(key string) {
 	server, ok := c.mapping[key]
 	if !ok {
@@ -139,6 +152,16 @@ func (c *container) getValues() []string {
 	return vals
 }
 
+func (c *container) notifyChange() {
+	c.lock.Lock()
+	listeners := append(([]func())(nil), c.listeners...)
+	c.lock.Unlock()
+
+	for _, listener := range listeners {
+		listener()
+	}
+}
+
 // removeKey removes the kv, returns true if there are still other keys associate with the value
 func (c *container) removeKey(key string) {
 	c.lock.Lock()

core/discov/subscriber_test.go

@@ -168,8 +168,13 @@ func TestContainer(t *testing.T) {
 	for _, test := range tests {
 		for _, exclusive := range exclusives {
 			t.Run(test.name, func(t *testing.T) {
+				var changed bool
 				c := newContainer(exclusive)
+				c.addListener(func() {
+					changed = true
+				})
 				assert.Nil(t, c.getValues())
+				assert.False(t, changed)
 
 				for _, order := range test.do {
 					if order.act == actionAdd {
@@ -185,6 +190,7 @@ func TestContainer(t *testing.T) {
 					}
 				}
 
+				assert.True(t, changed)
 				assert.True(t, c.dirty.True())
 				assert.ElementsMatch(t, test.expect, c.getValues())
 				assert.False(t, c.dirty.True())