Revert "graph: refactor Builder network message handling"

This reverts commit d757b3b.

graph/builder.go

@@ -123,6 +123,11 @@ type Builder struct {
 	// of our currently known best chain are sent over.
 	staleBlocks <-chan *chainview.FilteredBlock
 
+	// networkUpdates is a channel that carries new topology updates
+	// messages from outside the Builder to be processed by the
+	// networkHandler.
+	networkUpdates chan *routingMsg
+
 	// topologyClients maps a client's unique notification ID to a
 	// topologyClient client that contains its notification dispatch
 	// channel.
@@ -159,6 +164,7 @@ var _ ChannelGraphSource = (*Builder)(nil)
 func NewBuilder(cfg *Config) (*Builder, error) {
 	return &Builder{
 		cfg:               cfg,
+		networkUpdates:    make(chan *routingMsg),
 		topologyClients:   &lnutils.SyncMap[uint64, *topologyClient]{},
 		ntfnClientUpdates: make(chan *topologyClientUpdate),
 		channelEdgeMtx:    multimutex.NewMutex[uint64](),
@@ -707,8 +713,8 @@ func (b *Builder) handleNetworkUpdate(update *routingMsg) {
 
 // networkHandler is the primary goroutine for the Builder. The roles of
 // this goroutine include answering queries related to the state of the
-// network, pruning the graph on new block notification and registering new
-// topology clients.
+// network, pruning the graph on new block notification, applying network
+// updates, and registering new topology clients.
 //
 // NOTE: This MUST be run as a goroutine.
 func (b *Builder) networkHandler() {
@@ -728,6 +734,17 @@ func (b *Builder) networkHandler() {
 		}
 
 		select {
+		// A new fully validated network update has just arrived. As a
+		// result we'll modify the channel graph accordingly depending
+		// on the exact type of the message.
+		case update := <-b.networkUpdates:
+			b.wg.Add(1)
+			go b.handleNetworkUpdate(update)
+
+			// TODO(roasbeef): remove all unconnected vertexes
+			// after N blocks pass with no corresponding
+			// announcements.
+
 		case chainUpdate, ok := <-b.staleBlocks:
 			// If the channel has been closed, then this indicates
 			// the daemon is shutting down, so we exit ourselves.
@@ -1091,12 +1108,14 @@ func (b *Builder) AddNode(node *models.LightningNode,
 		err: make(chan error, 1),
 	}
 
-	b.wg.Add(1)
-	go b.handleNetworkUpdate(rMsg)
-
 	select {
-	case err := <-rMsg.err:
-		return err
+	case b.networkUpdates <- rMsg:
+		select {
+		case err := <-rMsg.err:
+			return err
+		case <-b.quit:
+			return ErrGraphBuilderShuttingDown
+		}
 	case <-b.quit:
 		return ErrGraphBuilderShuttingDown
 	}
@@ -1142,12 +1161,14 @@ func (b *Builder) AddEdge(edge *models.ChannelEdgeInfo,
 		err: make(chan error, 1),
 	}
 
-	b.wg.Add(1)
-	go b.handleNetworkUpdate(rMsg)
-
 	select {
-	case err := <-rMsg.err:
-		return err
+	case b.networkUpdates <- rMsg:
+		select {
+		case err := <-rMsg.err:
+			return err
+		case <-b.quit:
+			return ErrGraphBuilderShuttingDown
+		}
 	case <-b.quit:
 		return ErrGraphBuilderShuttingDown
 	}
@@ -1250,12 +1271,14 @@ func (b *Builder) UpdateEdge(update *models.ChannelEdgePolicy,
 		err: make(chan error, 1),
 	}
 
-	b.wg.Add(1)
-	go b.handleNetworkUpdate(rMsg)
-
 	select {
-	case err := <-rMsg.err:
-		return err
+	case b.networkUpdates <- rMsg:
+		select {
+		case err := <-rMsg.err:
+			return err
+		case <-b.quit:
+			return ErrGraphBuilderShuttingDown
+		}
 	case <-b.quit:
 		return ErrGraphBuilderShuttingDown
 	}