emit event for peer disconnectionsa and act upon them in the blocksyn…

…c peer tracker

chain/exchange/peer_tracker.go

@@ -11,6 +11,7 @@ import (
 	host "github.com/libp2p/go-libp2p-core/host"
 	"github.com/libp2p/go-libp2p-core/peer"
 	"go.uber.org/fx"
+	"go.uber.org/multierr"
 
 	"github.com/filecoin-project/lotus/build"
 	"github.com/filecoin-project/lotus/lib/peermgr"
@@ -38,20 +39,34 @@ func newPeerTracker(lc fx.Lifecycle, h host.Host, pmgr *peermgr.PeerMgr) *bsPeer
 		pmgr:  pmgr,
 	}
 
-	sub, err := h.EventBus().Subscribe(new(peermgr.NewFilPeer))
+	addSub, err := h.EventBus().Subscribe(new(peermgr.NewFilPeer))
 	if err != nil {
 		panic(err)
 	}
 
 	go func() {
-		for newPeer := range sub.Out() {
+		for newPeer := range addSub.Out() {
 			bsPt.addPeer(newPeer.(peermgr.NewFilPeer).Id)
 		}
 	}()
 
+	rmSub, err := h.EventBus().Subscribe(new(peermgr.RemoveFilPeer))
+	if err != nil {
+		panic(err)
+	}
+
+	go func() {
+		for rmPeer := range rmSub.Out() {
+			bsPt.removePeer(rmPeer.(peermgr.RemoveFilPeer).Id)
+		}
+	}()
+
 	lc.Append(fx.Hook{
 		OnStop: func(ctx context.Context) error {
-			return sub.Close()
+			return multierr.Combine(
+				addSub.Close(),
+				rmSub.Close(),
+			)
 		},
 	})
 

lib/peermgr/peermgr.go

@@ -54,7 +54,8 @@ type PeerMgr struct {
 	dht *dht.IpfsDHT
 
 	notifee        *net.NotifyBundle
-	filPeerEmitter event.Emitter
+	addPeerEmitter event.Emitter
+	rmPeerEmitter  event.Emitter
 
 	done chan struct{}
 }
@@ -63,6 +64,10 @@ type NewFilPeer struct {
 	Id peer.ID
 }
 
+type RemoveFilPeer struct {
+	Id peer.ID
+}
+
 func NewPeerMgr(lc fx.Lifecycle, h host.Host, dht *dht.IpfsDHT, bootstrap dtypes.BootstrapPeers) (*PeerMgr, error) {
 	pm := &PeerMgr{
 		h:             h,
@@ -81,12 +86,19 @@ func NewPeerMgr(lc fx.Lifecycle, h host.Host, dht *dht.IpfsDHT, bootstrap dtypes
 	if err != nil {
 		return nil, xerrors.Errorf("creating NewFilPeer emitter: %w", err)
 	}
-	pm.filPeerEmitter = emitter
+	pm.addPeerEmitter = emitter
+
+	emitter, err = h.EventBus().Emitter(new(RemoveFilPeer))
+	if err != nil {
+		return nil, xerrors.Errorf("creating RemoveFilPeer emitter: %w", err)
+	}
+	pm.rmPeerEmitter = emitter
 
 	lc.Append(fx.Hook{
 		OnStop: func(ctx context.Context) error {
 			return multierr.Combine(
-				pm.filPeerEmitter.Close(),
+				pm.addPeerEmitter.Close(),
+				pm.rmPeerEmitter.Close(),
 				pm.Stop(ctx),
 			)
 		},
@@ -104,7 +116,7 @@ func NewPeerMgr(lc fx.Lifecycle, h host.Host, dht *dht.IpfsDHT, bootstrap dtypes
 }
 
 func (pmgr *PeerMgr) AddFilecoinPeer(p peer.ID) {
-	_ = pmgr.filPeerEmitter.Emit(NewFilPeer{Id: p}) //nolint:errcheck
+	_ = pmgr.addPeerEmitter.Emit(NewFilPeer{Id: p}) //nolint:errcheck
 	pmgr.peersLk.Lock()
 	defer pmgr.peersLk.Unlock()
 	pmgr.peers[p] = time.Duration(0)
@@ -127,10 +139,19 @@ func (pmgr *PeerMgr) SetPeerLatency(p peer.ID, latency time.Duration) {
 }
 
 func (pmgr *PeerMgr) Disconnect(p peer.ID) {
+	disconnected := false
+
 	if pmgr.h.Network().Connectedness(p) == net.NotConnected {
 		pmgr.peersLk.Lock()
-		defer pmgr.peersLk.Unlock()
-		delete(pmgr.peers, p)
+		_, disconnected = pmgr.peers[p]
+		if disconnected {
+			delete(pmgr.peers, p)
+		}
+		pmgr.peersLk.Unlock()
+	}
+
+	if disconnected {
+		_ = pmgr.rmPeerEmitter.Emit(RemoveFilPeer{Id: p}) //nolint:errcheck
 	}
 }