Support multiple notifiers in 'libp2p.Service' (#551)

* Rename function 'SetNotifier' to 'AddNotifier'

* Support multiple notifiers in 'libp2p.Service'

pkg/node/node.go

@@ -205,7 +205,7 @@ func NewBee(addr string, logger logging.Logger, o Options) (*Bee, error) {
 	topologyDriver := kademlia.New(kademlia.Options{Base: address, Discovery: hive, AddressBook: addressbook, P2P: p2ps, Logger: logger})
 	b.topologyCloser = topologyDriver
 	hive.SetPeerAddedHandler(topologyDriver.AddPeer)
-	p2ps.SetNotifier(topologyDriver)
+	p2ps.AddNotifier(topologyDriver)
 	addrs, err := p2ps.Addresses()
 	if err != nil {
 		return nil, fmt.Errorf("get server addresses: %w", err)

pkg/p2p/libp2p/connections_test.go

@@ -346,11 +346,11 @@ func TestTopologyNotifier(t *testing.T) {
 	)
 	notifier1 := mockNotifier(n1c, n1d)
 	s1, overlay1 := newService(t, 1, libp2pServiceOpts{Addressbook: ab1})
-	s1.SetNotifier(notifier1)
+	s1.AddNotifier(notifier1)
 
 	notifier2 := mockNotifier(n2c, n2d)
 	s2, overlay2 := newService(t, 1, libp2pServiceOpts{Addressbook: ab2})
-	s2.SetNotifier(notifier2)
+	s2.AddNotifier(notifier2)
 
 	addr := serviceUnderlayAddress(t, s1)
 
@@ -430,7 +430,7 @@ func TestTopologyLocalNotifier(t *testing.T) {
 	notifier2 := mockNotifier(n2c, n2d)
 
 	s2, overlay2 := newService(t, 1, libp2pServiceOpts{})
-	s2.SetNotifier(notifier2)
+	s2.AddNotifier(notifier2)
 
 	addr := serviceUnderlayAddress(t, s1)
 
@@ -447,6 +447,55 @@ func TestTopologyLocalNotifier(t *testing.T) {
 	waitAddrSet(t, &n2connectedAddr, &mtx, overlay1)
 }
 
+func TestTopologySupportMultipleNotifiers(t *testing.T) {
+	var (
+		mtx              sync.Mutex
+		n21connectedAddr swarm.Address
+		n22connectedAddr swarm.Address
+
+		n21c = func(_ context.Context, a swarm.Address) error {
+			mtx.Lock()
+			defer mtx.Unlock()
+			n21connectedAddr = a
+			return nil
+		}
+		n21d = func(a swarm.Address) {
+		}
+
+		n22c = func(_ context.Context, a swarm.Address) error {
+			mtx.Lock()
+			defer mtx.Unlock()
+			n22connectedAddr = a
+			return nil
+		}
+		n22d = func(a swarm.Address) {
+		}
+	)
+
+	s1, overlay1 := newService(t, 1, libp2pServiceOpts{})
+	notifier21 := mockNotifier(n21c, n21d)
+	notifier22 := mockNotifier(n22c, n22d)
+
+	s2, overlay2 := newService(t, 1, libp2pServiceOpts{})
+	s2.AddNotifier(notifier21)
+	s2.AddNotifier(notifier22)
+
+	addr := serviceUnderlayAddress(t, s1)
+
+	// s2 connects to s1, thus the notifier on s1 should be called on Connect
+	_, err := s2.ConnectNotify(context.Background(), addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectPeers(t, s2, overlay1)
+	expectPeersEventually(t, s1, overlay2)
+
+	// expect that n1 notifee called with s2 overlay
+	waitAddrSet(t, &n21connectedAddr, &mtx, overlay1)
+	waitAddrSet(t, &n22connectedAddr, &mtx, overlay1)
+}
+
 func waitAddrSet(t *testing.T, addr *swarm.Address, mtx *sync.Mutex, exp swarm.Address) {
 	t.Helper()
 	for i := 0; i < 20; i++ {

pkg/p2p/libp2p/libp2p.go

@@ -53,7 +53,7 @@ type Service struct {
 	handshakeService  *handshake.Service
 	addressbook       addressbook.Putter
 	peers             *peerRegistry
-	topologyNotifier  topology.Notifier
+	topologyNotifiers []topology.Notifier
 	connectionBreaker breaker.Interface
 	logger            logging.Logger
 	tracer            *tracing.Tracer
@@ -241,11 +241,13 @@ func New(ctx context.Context, signer beecrypto.Signer, networkID uint64, overlay
 			return
 		}
 
-		if s.topologyNotifier != nil {
-			if err := s.topologyNotifier.Connected(ctx, i.BzzAddress.Overlay); err != nil {
+		if len(s.topologyNotifiers) > 0 {
+			for _, tn := range s.topologyNotifiers {
+				if err := tn.Connected(ctx, i.BzzAddress.Overlay); err != nil {
 					s.logger.Debugf("topology notifier: %s: %v", peerID, err)
 				}
 			}
+		}
 
 		s.metrics.HandledStreamCount.Inc()
 		s.logger.Infof("successfully connected to peer (inbound) %s", i.BzzAddress.ShortString())
@@ -354,12 +356,16 @@ func (s *Service) ConnectNotify(ctx context.Context, addr ma.Multiaddr) (address
 	if err != nil {
 		return nil, fmt.Errorf("connect notify: %w", err)
 	}
-	if s.topologyNotifier != nil {
-		if err := s.topologyNotifier.Connected(ctx, address.Overlay); err != nil {
+
+	if len(s.topologyNotifiers) > 0 {
+		for _, tn := range s.topologyNotifiers {
+			if err := tn.Connected(ctx, address.Overlay); err != nil {
 				_ = s.disconnect(info.ID)
 				return nil, fmt.Errorf("notify topology: %w", err)
 			}
 		}
+	}
+
 	return address, nil
 }
 
@@ -423,7 +429,7 @@ func (s *Service) Connect(ctx context.Context, addr ma.Multiaddr) (address *bzz.
 func (s *Service) Disconnect(overlay swarm.Address) error {
 	peerID, found := s.peers.peerID(overlay)
 	if !found {
-		s.peers.disconnecter.Disconnected(overlay)
+		s.peers.disconnect(overlay)
 		return p2p.ErrPeerNotFound
 	}
 
@@ -442,15 +448,15 @@ func (s *Service) Peers() []p2p.Peer {
 	return s.peers.peers()
 }
 
-func (s *Service) SetNotifier(n topology.Notifier) {
-	s.topologyNotifier = n
-	s.peers.setDisconnecter(n)
+func (s *Service) AddNotifier(n topology.Notifier) {
+	s.topologyNotifiers = append(s.topologyNotifiers, n)
+	s.peers.addDisconnecter(n)
 }
 
 func (s *Service) NewStream(ctx context.Context, overlay swarm.Address, headers p2p.Headers, protocolName, protocolVersion, streamName string) (p2p.Stream, error) {
 	peerID, found := s.peers.peerID(overlay)
 	if !found {
-		s.peers.disconnecter.Disconnected(overlay)
+		s.peers.disconnect(overlay)
 		return nil, p2p.ErrPeerNotFound
 	}
 

pkg/p2p/libp2p/libp2p_test.go

@@ -70,7 +70,7 @@ func newService(t *testing.T, networkID uint64, o libp2pServiceOpts) (s *libp2p.
 		t.Fatal(err)
 	}
 
-	s.SetNotifier(noopNotifier)
+	s.AddNotifier(noopNotifier)
 
 	t.Cleanup(func() {
 		cancel()

pkg/p2p/libp2p/peer.go

@@ -24,7 +24,8 @@ type peerRegistry struct {
 	streams     map[libp2ppeer.ID]map[network.Stream]context.CancelFunc
 	mu          sync.RWMutex
 
-	disconnecter     topology.Disconnecter // peerRegistry notifies topology on peer disconnection
+	//nolint:misspell
+	disconnecters    []topology.Disconnecter // peerRegistry notifies topology on peer disconnection
 	network.Notifiee                         // peerRegistry can be the receiver for network.Notify
 }
 
@@ -73,8 +74,11 @@ func (r *peerRegistry) Disconnected(_ network.Network, c network.Conn) {
 	delete(r.streams, peerID)
 
 	r.mu.Unlock()
-	if r.disconnecter != nil {
-		r.disconnecter.Disconnected(overlay)
+
+	if len(r.disconnecters) > 0 {
+		for _, d := range r.disconnecters {
+			d.Disconnected(overlay)
+		}
 	}
 }
 
@@ -169,11 +173,19 @@ func (r *peerRegistry) remove(peerID libp2ppeer.ID) {
 	r.mu.Unlock()
 
 	// if overlay was not found disconnect handler should not be signaled.
-	if r.disconnecter != nil && found {
-		r.disconnecter.Disconnected(overlay)
+	if len(r.disconnecters) > 0 && found {
+		for _, d := range r.disconnecters {
+			d.Disconnected(overlay)
+		}
 	}
 }
 
-func (r *peerRegistry) setDisconnecter(d topology.Disconnecter) {
-	r.disconnecter = d
+func (r *peerRegistry) addDisconnecter(d topology.Disconnecter) {
+	r.disconnecters = append(r.disconnecters, d)
+}
+
+func (r *peerRegistry) disconnect(address swarm.Address) {
+	for _, d := range r.disconnecters {
+		d.Disconnected(address)
+	}
 }

pkg/p2p/mock/mock.go

@@ -22,7 +22,7 @@ type Service struct {
 	connectFunc           func(ctx context.Context, addr ma.Multiaddr) (address *bzz.Address, err error)
 	disconnectFunc        func(overlay swarm.Address) error
 	peersFunc             func() []p2p.Peer
-	setNotifierFunc       func(topology.Notifier)
+	addNotifierFunc       func(topology.Notifier)
 	addressesFunc         func() ([]ma.Multiaddr, error)
 	setWelcomeMessageFunc func(string) error
 	getWelcomeMessageFunc func() string
@@ -58,10 +58,10 @@ func WithPeersFunc(f func() []p2p.Peer) Option {
 	})
 }
 
-// WithSetNotifierFunc sets the mock implementation of the SetNotifier function
-func WithSetNotifierFunc(f func(topology.Notifier)) Option {
+// WithAddNotifierFunc sets the mock implementation of the AddNotifier function
+func WithAddNotifierFunc(f func(topology.Notifier)) Option {
 	return optionFunc(func(s *Service) {
-		s.setNotifierFunc = f
+		s.addNotifierFunc = f
 	})
 }
 
@@ -124,12 +124,12 @@ func (s *Service) Disconnect(overlay swarm.Address) error {
 	return s.disconnectFunc(overlay)
 }
 
-func (s *Service) SetNotifier(f topology.Notifier) {
-	if s.setNotifierFunc == nil {
+func (s *Service) AddNotifier(f topology.Notifier) {
+	if s.addNotifierFunc == nil {
 		return
 	}
 
-	s.setNotifierFunc(f)
+	s.addNotifierFunc(f)
 }
 
 func (s *Service) Addresses() ([]ma.Multiaddr, error) {

pkg/p2p/p2p.go

@@ -24,7 +24,7 @@ type Service interface {
 	Connect(ctx context.Context, addr ma.Multiaddr) (address *bzz.Address, err error)
 	Disconnect(overlay swarm.Address) error
 	Peers() []Peer
-	SetNotifier(topology.Notifier)
+	AddNotifier(topology.Notifier)
 	Addresses() ([]ma.Multiaddr, error)
 }