refactor: extract function to subscribe to topic

waku/v2/node/wakunode2.go

@@ -389,52 +389,54 @@ func (node *WakuNode) Subscribe(ctx context.Context, topic *relay.Topic) (*Subsc
 
 	node.bcaster.Register(subscription.C)
 
-	go func(t relay.Topic) {
-		nextMsgTicker := time.NewTicker(time.Millisecond * 10)
-		defer nextMsgTicker.Stop()
-
-		ctx, err := tag.New(node.ctx, tag.Insert(metrics.KeyType, "relay"))
-		if err != nil {
-			log.Error(err)
-			return
-		}
-
-		for {
-			select {
-			case <-subscription.quit:
-				subscription.mutex.Lock()
-				node.bcaster.Unregister(subscription.C) // Remove from broadcast list
-				close(subscription.C)
-				subscription.mutex.Unlock()
-			case <-nextMsgTicker.C:
-				msg, err := sub.Next(ctx)
-				if err != nil {
-					subscription.mutex.Lock()
-					for _, subscription := range node.subscriptions[t] {
-						subscription.Unsubscribe()
-					}
-					subscription.mutex.Unlock()
-					return
-				}
-
-				stats.Record(ctx, metrics.Messages.M(1))
-
-				wakuMessage := &pb.WakuMessage{}
-				if err := proto.Unmarshal(msg.Data, wakuMessage); err != nil {
-					log.Error("could not decode message", err)
-					return
-				}
-
-				envelope := protocol.NewEnvelope(wakuMessage, string(t))
-
-				node.bcaster.Submit(envelope)
-			}
-		}
-	}(t)
+	go node.subscribeToTopic(t, subscription, sub)
 
 	return subscription, nil
 }
 
+func (node *WakuNode) subscribeToTopic(t relay.Topic, subscription *Subscription, sub *pubsub.Subscription) {
+	nextMsgTicker := time.NewTicker(time.Millisecond * 10)
+	defer nextMsgTicker.Stop()
+
+	ctx, err := tag.New(node.ctx, tag.Insert(metrics.KeyType, "relay"))
+	if err != nil {
+		log.Error(err)
+		return
+	}
+
+	for {
+		select {
+		case <-subscription.quit:
+			subscription.mutex.Lock()
+			node.bcaster.Unregister(subscription.C) // Remove from broadcast list
+			close(subscription.C)
+			subscription.mutex.Unlock()
+		case <-nextMsgTicker.C:
+			msg, err := sub.Next(ctx)
+			if err != nil {
+				subscription.mutex.Lock()
+				for _, subscription := range node.subscriptions[t] {
+					subscription.Unsubscribe()
+				}
+				subscription.mutex.Unlock()
+				return
+			}
+
+			stats.Record(ctx, metrics.Messages.M(1))
+
+			wakuMessage := &pb.WakuMessage{}
+			if err := proto.Unmarshal(msg.Data, wakuMessage); err != nil {
+				log.Error("could not decode message", err)
+				return
+			}
+
+			envelope := protocol.NewEnvelope(wakuMessage, string(t))
+
+			node.bcaster.Submit(envelope)
+		}
+	}
+}
+
 // Wrapper around WakuFilter.Subscribe
 // that adds a Filter object to node.filters
 // TODO: what's up with this channel?.......................... is it closed eventually?