Fix simultaneous stream reconnect and start

cmd/streams/producer.go

@@ -27,9 +27,9 @@ type Producer struct {
 	lastErr error
 	tracks  []*streamer.Track
 
-	state   state
-	mu      sync.Mutex
-	restart *time.Timer
+	state    state
+	mu       sync.Mutex
+	workerID int
 }
 
 func (p *Producer) SetSource(s string) {
@@ -104,20 +104,32 @@ func (p *Producer) start() {
 	log.Debug().Msgf("[streams] start producer url=%s", p.url)
 
 	p.state = stateStart
-	go func() {
-		// safe read element while mu locked
-		if err := p.element.Start(); err != nil {
-			log.Warn().Err(err).Str("url", p.url).Caller().Send()
-		}
-		p.reconnect()
-	}()
+	p.workerID++
+
+	go p.worker(p.element, p.workerID)
 }
 
-func (p *Producer) reconnect() {
+func (p *Producer) worker(element streamer.Producer, workerID int) {
+	if err := element.Start(); err != nil {
+		p.mu.Lock()
+		closed := p.workerID != workerID
+		p.mu.Unlock()
+
+		if closed {
+			return
+		}
+
+		log.Warn().Err(err).Str("url", p.url).Caller().Send()
+	}
+
+	p.reconnect(workerID)
+}
+
+func (p *Producer) reconnect(workerID int) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
 
-	if p.state != stateStart {
+	if p.workerID != workerID {
 		log.Trace().Msgf("[streams] stop reconnect url=%s", p.url)
 		return
 	}
@@ -126,9 +138,11 @@ func (p *Producer) reconnect() {
 
 	p.element, p.lastErr = GetProducer(p.url)
 	if p.lastErr != nil || p.element == nil {
-		log.Debug().Err(p.lastErr).Caller().Send()
+		log.Debug().Msgf("[streams] producer=%s", p.lastErr)
 		// TODO: dynamic timeout
-		p.restart = time.AfterFunc(30*time.Second, p.reconnect)
+		time.AfterFunc(30*time.Second, func() {
+			p.reconnect(workerID)
+		})
 		return
 	}
 
@@ -152,12 +166,7 @@ func (p *Producer) reconnect() {
 		}
 	}
 
-	go func() {
-		if err := p.element.Start(); err != nil {
-			log.Debug().Err(err).Caller().Send()
-		}
-		p.reconnect()
-	}()
+	go p.worker(p.element, workerID)
 }
 
 func (p *Producer) stop() {
@@ -171,6 +180,8 @@ func (p *Producer) stop() {
 	case stateNone:
 		log.Debug().Msgf("[streams] can't stop none producer")
 		return
+	case stateStart:
+		p.workerID++
 	}
 
 	log.Debug().Msgf("[streams] stop producer url=%s", p.url)
@@ -179,10 +190,6 @@ func (p *Producer) stop() {
 		_ = p.element.Stop()
 		p.element = nil
 	}
-	if p.restart != nil {
-		p.restart.Stop()
-		p.restart = nil
-	}
 
 	p.state = stateNone
 	p.tracks = nil