chore: add artificial delay to peer-exchange

waku/v2/discv5/discover.go

@@ -313,27 +313,27 @@ func (d *DiscoveryV5) PeerIterator(predicate ...Predicate) (enode.Iterator, erro
 	return iterator, nil
 }
 
+func DelayEveryNPeers(ctx context.Context, peerCnt int) int {
+	peerCnt++
+	if peerCnt == bucketSize { // Delay every bucketSize peers discovered
+		peerCnt = 0
+		t := time.NewTimer(delayBetweenDiscoveredPeerCnt)
+		select {
+		case <-ctx.Done():
+			return peerCnt
+		case <-t.C:
+			t.Stop()
+		}
+	}
+	return peerCnt
+}
+
 func (d *DiscoveryV5) Iterate(ctx context.Context, iterator enode.Iterator, onNode func(*enode.Node, peer.AddrInfo) error) {
 	defer iterator.Close()
 
 	peerCnt := 0
-	for {
-
-		if !delayedHasNext(ctx, iterator) {
-			return
-		}
-
-		peerCnt++
-		if peerCnt == bucketSize { // Delay every bucketSize peers discovered
-			peerCnt = 0
-			t := time.NewTimer(delayBetweenDiscoveredPeerCnt)
-			select {
-			case <-ctx.Done():
-				return
-			case <-t.C:
-				t.Stop()
-			}
-		}
+	for DelayedHasNext(ctx, iterator) {
+		peerCnt = DelayEveryNPeers(ctx, peerCnt)
 
 		_, addresses, err := wenr.Multiaddress(iterator.Node())
 		if err != nil {
@@ -364,7 +364,7 @@ func (d *DiscoveryV5) Iterate(ctx context.Context, iterator enode.Iterator, onNo
 	}
 }
 
-func delayedHasNext(ctx context.Context, iterator enode.Iterator) bool {
+func DelayedHasNext(ctx context.Context, iterator enode.Iterator) bool {
 	// Delay if .Next() is too fast
 	start := time.Now()
 	hasNext := iterator.Next()

waku/v2/protocol/peer_exchange/protocol.go

@@ -144,7 +144,10 @@ func (wakuPX *WakuPeerExchange) iterate(ctx context.Context) error {
 	// Closing iterator
 	defer iterator.Close()
 
-	for iterator.Next() {
+	peerCnt := 0
+	for discv5.DelayedHasNext(ctx, iterator) {
+		peerCnt = discv5.DelayEveryNPeers(ctx, peerCnt)
+
 		_, addresses, err := enr.Multiaddress(iterator.Node())
 		if err != nil {
 			wakuPX.log.Error("extracting multiaddrs from enr", zap.Error(err))