add fix and test (#6533)

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

beacon-chain/sync/metrics.go

@@ -9,6 +9,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	pb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
 var (
@@ -92,10 +94,17 @@ func (s *Service) updateMetrics() {
 	indices := s.aggregatorSubnetIndices(s.chain.CurrentSlot())
 	attTopic := p2p.GossipTypeMapping[reflect.TypeOf(&pb.Attestation{})]
 	attTopic += s.p2p.Encoding().ProtocolSuffix()
+	if featureconfig.Get().DisableDynamicCommitteeSubnets {
+		for i := uint64(0); i < params.BeaconNetworkConfig().AttestationSubnetCount; i++ {
+			formattedTopic := fmt.Sprintf(attTopic, digest, i)
+			topicPeerCount.WithLabelValues(formattedTopic).Set(float64(len(s.p2p.PubSub().ListPeers(formattedTopic))))
+		}
+	} else {
 		for _, committeeIdx := range indices {
 			formattedTopic := fmt.Sprintf(attTopic, digest, committeeIdx)
 			topicPeerCount.WithLabelValues(formattedTopic).Set(float64(len(s.p2p.PubSub().ListPeers(formattedTopic))))
 		}
+	}
 	// We update all other gossip topics.
 	for topic := range p2p.GossipTopicMappings {
 		// We already updated attestation subnet topics.

beacon-chain/sync/subscriber.go

@@ -73,13 +73,11 @@ func (s *Service) registerSubscribers() {
 		s.attesterSlashingSubscriber,
 	)
 	if featureconfig.Get().DisableDynamicCommitteeSubnets {
-		for i := uint64(0); i < params.BeaconNetworkConfig().AttestationSubnetCount; i++ {
-			s.subscribe(
-				fmt.Sprintf("/eth2/%%x/beacon_attestation_%d", i),
+		s.subscribeStaticWithSubnets(
+			"/eth2/%x/beacon_attestation_%d",
 			s.validateCommitteeIndexBeaconAttestation,   /* validator */
 			s.committeeIndexBeaconAttestationSubscriber, /* message handler */
 		)
-		}
 	} else {
 		s.subscribeDynamicWithSubnets(
 			"/eth2/%x/beacon_attestation_%d",
@@ -187,6 +185,49 @@ func wrapAndReportValidation(topic string, v pubsub.ValidatorEx) (string, pubsub
 	}
 }
 
+// subscribe to a static subnet  with the given topic and index.A given validator and subscription handler is
+// used to handle messages from the subnet. The base protobuf message is used to initialize new messages for decoding.
+func (s *Service) subscribeStaticWithSubnets(topic string, validator pubsub.ValidatorEx, handle subHandler) {
+	base := p2p.GossipTopicMappings[topic]
+	if base == nil {
+		panic(fmt.Sprintf("%s is not mapped to any message in GossipTopicMappings", topic))
+	}
+	for i := uint64(0); i < params.BeaconNetworkConfig().AttestationSubnetCount; i++ {
+		s.subscribeWithBase(base, s.addDigestAndIndexToTopic(topic, i), validator, handle)
+	}
+	genesis := s.chain.GenesisTime()
+	ticker := slotutil.GetSlotTicker(genesis, params.BeaconConfig().SecondsPerSlot)
+
+	go func() {
+		for {
+			select {
+			case <-s.ctx.Done():
+				ticker.Done()
+				return
+			case <-ticker.C():
+				if s.chainStarted && s.initialSync.Syncing() {
+					continue
+				}
+				// Check every slot that there are enough peers
+				for i := uint64(0); i < params.BeaconNetworkConfig().AttestationSubnetCount; i++ {
+					if !s.validPeersExist(topic, i) {
+						log.Debugf("No peers found subscribed to attestation gossip subnet with "+
+							"committee index %d. Searching network for peers subscribed to the subnet.", i)
+						go func(idx uint64) {
+							_, err := s.p2p.FindPeersWithSubnet(idx)
+							if err != nil {
+								log.Errorf("Could not search for peers: %v", err)
+								return
+							}
+						}(i)
+						return
+					}
+				}
+			}
+		}
+	}()
+}
+
 // subscribe to a dynamically changing list of subnets. This method expects a fmt compatible
 // string for the topic name and the list of subnets for subscribed topics that should be
 // maintained.
@@ -325,6 +366,18 @@ func (s *Service) addDigestToTopic(topic string) string {
 	return fmt.Sprintf(topic, digest)
 }
 
+// Add the digest and index to subnet topic.
+func (s *Service) addDigestAndIndexToTopic(topic string, idx uint64) string {
+	if !strings.Contains(topic, "%x") {
+		log.Fatal("Topic does not have appropriate formatter for digest")
+	}
+	digest, err := s.forkDigest()
+	if err != nil {
+		log.WithError(err).Fatal("Could not compute fork digest")
+	}
+	return fmt.Sprintf(topic, digest, idx)
+}
+
 func (s *Service) forkDigest() ([4]byte, error) {
 	genRoot := s.chain.GenesisValidatorRoot()
 	return p2putils.CreateForkDigest(s.chain.GenesisTime(), genRoot[:])

beacon-chain/sync/subscriber_test.go

@@ -261,3 +261,26 @@ func TestRevalidateSubscription_CorrectlyFormatsTopic(t *testing.T) {
 	r.reValidateSubscriptions(subscriptions, []uint64{2}, defaultTopic, digest)
 	testutil.AssertLogsDoNotContain(t, hook, "Failed to unregister topic validator")
 }
+
+func TestStaticSubnets(t *testing.T) {
+	p := p2ptest.NewTestP2P(t)
+	ctx, cancel := context.WithCancel(context.Background())
+	r := Service{
+		ctx: ctx,
+		chain: &mockChain.ChainService{
+			Genesis:        time.Now(),
+			ValidatorsRoot: [32]byte{'A'},
+		},
+		p2p: p,
+	}
+	defaultTopic := "/eth2/%x/beacon_attestation_%d"
+	r.subscribeStaticWithSubnets(defaultTopic, r.noopValidator, func(_ context.Context, msg proto.Message) error {
+		// no-op
+		return nil
+	})
+	topics := r.p2p.PubSub().GetTopics()
+	if uint64(len(topics)) != params.BeaconNetworkConfig().AttestationSubnetCount {
+		t.Errorf("Wanted the number of subnet topics registered to be %d but got %d", params.BeaconNetworkConfig().AttestationSubnetCount, len(topics))
+	}
+	cancel()
+}