peer+server: remove persistent connections for peers with no open channels remaining

peer.go

@@ -1692,9 +1692,6 @@ func (p *peer) fetchActiveChanCloser(chanID lnwire.ChannelID) (*channelCloser, e
 
 // handleLocalCloseReq kicks-off the workflow to execute a cooperative or
 // forced unilateral closure of the channel initiated by a local subsystem.
-//
-// TODO(roasbeef): if no more active channels with peer call Remove on connMgr
-// with peerID
 func (p *peer) handleLocalCloseReq(req *htlcswitch.ChanClose) {
 	chanID := lnwire.NewChanIDFromOutPoint(req.ChanPoint)
 
@@ -1847,6 +1844,18 @@ func (p *peer) finalizeChanClosure(chanCloser *channelCloser) {
 					},
 				}
 			}
+
+			// Remove the persistent connection to this peer if we
+			// no longer have open channels with them.
+			p.activeChanMtx.Lock()
+			numActiveChans := len(p.activeChannels)
+			p.activeChanMtx.Unlock()
+
+			if numActiveChans == 0 {
+				p.server.prunePersistentPeerConnection(
+					p.pubKeyBytes,
+				)
+			}
 		})
 }
 
@@ -1900,6 +1909,9 @@ func (p *peer) WipeChannel(chanPoint *wire.OutPoint) error {
 	if channel, ok := p.activeChannels[chanID]; ok {
 		channel.Stop()
 		delete(p.activeChannels, chanID)
+		if len(p.activeChannels) == 0 {
+			p.server.prunePersistentPeerConnection(p.pubKeyBytes)
+		}
 	}
 	p.activeChanMtx.Unlock()
 

server.go

@@ -1476,6 +1476,22 @@ func (s *server) establishPersistentConnections() error {
 	return nil
 }
 
+// prunePersistentPeerConnection removes all internal state related to
+// persistent connections to a peer within the server. This is used to avoid
+// persistent connection retries to peers we do not have any open channels with.
+func (s *server) prunePersistentPeerConnection(compressedPubKey [33]byte) {
+	srvrLog.Infof("Pruning peer %x from persistent connections, number of "+
+		"open channels is now zero", compressedPubKey)
+
+	pubKeyStr := string(compressedPubKey[:])
+
+	s.mu.Lock()
+	delete(s.persistentPeers, pubKeyStr)
+	delete(s.persistentPeersBackoff, pubKeyStr)
+	s.cancelConnReqs(pubKeyStr, nil)
+	s.mu.Unlock()
+}
+
 // BroadcastMessage sends a request to the server to broadcast a set of
 // messages to all peers other than the one specified by the `skips` parameter.
 //