Merge pull request #35 from film42/gt/slow_announce

Drop announce messages to slow peers

floodsub.go

@@ -230,8 +230,12 @@ func (p *PubSub) announce(topic string, sub bool) {
 	}
 
 	out := rpcWithSubs(subopt)
-	for _, peer := range p.peers {
+	for pid, peer := range p.peers {
-		peer <- out
+		select {
+		case peer <- out:
+		default:
+			log.Infof("dropping announce message to peer %s: queue full", pid)
+		}
 	}
 }
 
@@ -259,6 +263,10 @@ func (p *PubSub) markSeen(id string) {
 // subscribedToMessage returns whether we are subscribed to one of the topics
 // of a given message
 func (p *PubSub) subscribedToMsg(msg *pb.Message) bool {
+	if len(p.myTopics) == 0 {
+		return false
+	}
+
 	for _, t := range msg.GetTopicIDs() {
 		if _, ok := p.myTopics[t]; ok {
 			return true