fix: setup shards (#1256)

cmd/waku/node.go

@@ -309,11 +309,6 @@ func Execute(options NodeOptions) error {
 		nodeOpts = append(nodeOpts, discv5Opts)
 	}
 
-	wakuNode, err := node.New(nodeOpts...)
-	if err != nil {
-		return fmt.Errorf("could not instantiate waku: %w", err)
-	}
-
 	//Process pubSub and contentTopics specified and arrive at all corresponding pubSubTopics
 	pubSubTopicMap, err := processTopics(options)
 	if err != nil {
@@ -325,6 +320,22 @@ func Execute(options NodeOptions) error {
 		pubSubTopicMapKeys = append(pubSubTopicMapKeys, k)
 	}
 
+	rs, err := wprotocol.TopicsToRelayShards(pubSubTopicMapKeys...)
+	if err == nil {
+		if len(rs) == 1 {
+			nodeOpts = append(nodeOpts, node.WithShards(rs[0].ShardIDs))
+		} else {
+			logger.Warn("could not set ENR shard info", zap.String("error", "invalid number of clusters found"), zap.Int("numClusters", len(rs)))
+		}
+	} else {
+		logger.Warn("could not obtain list of shards", zap.Error(err))
+	}
+
+	wakuNode, err := node.New(nodeOpts...)
+	if err != nil {
+		return fmt.Errorf("could not instantiate waku: %w", err)
+	}
+
 	if err = wakuNode.Start(ctx); err != nil {
 		return nonRecoverError(err)
 	}

waku/v2/node/wakunode2.go

@@ -464,15 +464,19 @@ func (w *WakuNode) Start(ctx context.Context) error {
 		if err != nil {
 			return err
 		}
-		//TODO: setting this up temporarily to improve connectivity success for lightNode in status.
+	}
-		//This will have to be removed or changed with community sharding will be implemented.
+
+	//TODO: setting this up temporarily to improve connectivity success for lightNode
+	//      in status. Also, when executing go-waku service-node as a lightclient
+	//      (using --pubsub-topic and --relay=false)
+	//      This will have to be removed or changed with community sharding will be
+	//      implemented.
 	if w.opts.shards != nil {
 		err = w.SetRelayShards(*w.opts.shards)
 		if err != nil {
 			return err
 		}
 	}
-	}
 
 	if w.opts.keepAliveRandomPeersInterval > time.Duration(0) || w.opts.keepAliveAllPeersInterval > time.Duration(0) {
 		w.wg.Add(1)