Merge pull request #19498 from mountkin/refactor-jsonfilelog-reader

use pubsub instead of filenotify to follow json logs

pubsub/publisher.go

@@ -54,18 +54,24 @@ func (p *Publisher) SubscribeTopic(topic topicFunc) chan interface{} {
 // Evict removes the specified subscriber from receiving any more messages.
 func (p *Publisher) Evict(sub chan interface{}) {
 	p.m.Lock()
-	delete(p.subscribers, sub)
-	close(sub)
+	if _, ok := p.subscribers[sub]; ok {
+		delete(p.subscribers, sub)
+		close(sub)
+	}
 	p.m.Unlock()
 }
 
 // Publish sends the data in v to all subscribers currently registered with the publisher.
 func (p *Publisher) Publish(v interface{}) {
 	p.m.RLock()
+	if len(p.subscribers) == 0 {
+		p.m.RUnlock()
+		return
+	}
+
 	wg := new(sync.WaitGroup)
 	for sub, topic := range p.subscribers {
 		wg.Add(1)
-
 		go p.sendTopic(sub, topic, v, wg)
 	}
 	wg.Wait()