graph+autopilot: let autopilot use new graph ForEachNode method

Which passes a NodeRTx to the call-back instead of a `kvdb.RTx`.

autopilot/graph.go

@@ -10,7 +10,6 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
-	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
@@ -51,11 +50,7 @@ func ChannelGraphFromDatabase(db *graphdb.ChannelGraph) ChannelGraph {
 // channeldb.LightningNode. The wrapper method implement the autopilot.Node
 // interface.
 type dbNode struct {
-	db *graphdb.ChannelGraph
-
-	tx kvdb.RTx
-
-	node *models.LightningNode
+	tx graphdb.NodeRTx
 }
 
 // A compile time assertion to ensure dbNode meets the autopilot.Node
@@ -68,7 +63,7 @@ var _ Node = (*dbNode)(nil)
 //
 // NOTE: Part of the autopilot.Node interface.
 func (d *dbNode) PubKey() [33]byte {
-	return d.node.PubKeyBytes
+	return d.tx.Node().PubKeyBytes
 }
 
 // Addrs returns a slice of publicly reachable public TCP addresses that the
@@ -76,7 +71,7 @@ func (d *dbNode) PubKey() [33]byte {
 //
 // NOTE: Part of the autopilot.Node interface.
 func (d *dbNode) Addrs() []net.Addr {
-	return d.node.Addresses
+	return d.tx.Node().Addresses
 }
 
 // ForEachChannel is a higher-order function that will be used to iterate
@@ -86,43 +81,35 @@ func (d *dbNode) Addrs() []net.Addr {
 //
 // NOTE: Part of the autopilot.Node interface.
 func (d *dbNode) ForEachChannel(cb func(ChannelEdge) error) error {
-	return d.db.ForEachNodeChannelTx(d.tx, d.node.PubKeyBytes,
-		func(tx kvdb.RTx, ei *models.ChannelEdgeInfo, ep,
-			_ *models.ChannelEdgePolicy) error {
+	return d.tx.ForEachChannel(func(ei *models.ChannelEdgeInfo, ep,
+		_ *models.ChannelEdgePolicy) error {
 
-			// Skip channels for which no outgoing edge policy is
-			// available.
-			//
-			// TODO(joostjager): Ideally the case where channels
-			// have a nil policy should be supported, as autopilot
-			// is not looking at the policies. For now, it is not
-			// easily possible to get a reference to the other end
-			// LightningNode object without retrieving the policy.
-			if ep == nil {
-				return nil
-			}
+		// Skip channels for which no outgoing edge policy is available.
+		//
+		// TODO(joostjager): Ideally the case where channels have a nil
+		// policy should be supported, as autopilot is not looking at
+		// the policies. For now, it is not easily possible to get a
+		// reference to the other end LightningNode object without
+		// retrieving the policy.
+		if ep == nil {
+			return nil
+		}
 
-			node, err := d.db.FetchLightningNodeTx(
-				tx, ep.ToNode,
-			)
-			if err != nil {
-				return err
-			}
+		node, err := d.tx.FetchNode(ep.ToNode)
+		if err != nil {
+			return err
+		}
 
-			edge := ChannelEdge{
-				ChanID: lnwire.NewShortChanIDFromInt(
-					ep.ChannelID,
-				),
-				Capacity: ei.Capacity,
-				Peer: &dbNode{
-					tx:   tx,
-					db:   d.db,
-					node: node,
-				},
-			}
+		edge := ChannelEdge{
+			ChanID:   lnwire.NewShortChanIDFromInt(ep.ChannelID),
+			Capacity: ei.Capacity,
+			Peer: &dbNode{
+				tx: node,
+			},
+		}
 
-			return cb(edge)
-		})
+		return cb(edge)
+	})
 }
 
 // ForEachNode is a higher-order function that should be called once for each
@@ -131,20 +118,16 @@ func (d *dbNode) ForEachChannel(cb func(ChannelEdge) error) error {
 //
 // NOTE: Part of the autopilot.ChannelGraph interface.
 func (d *databaseChannelGraph) ForEachNode(cb func(Node) error) error {
-	return d.db.ForEachNode(func(tx kvdb.RTx,
-		n *models.LightningNode) error {
-
+	return d.db.ForEachNode(func(nodeTx graphdb.NodeRTx) error {
 		// We'll skip over any node that doesn't have any advertised
 		// addresses. As we won't be able to reach them to actually
 		// open any channels.
-		if len(n.Addresses) == 0 {
+		if len(nodeTx.Node().Addresses) == 0 {
 			return nil
 		}
 
 		node := &dbNode{
-			db:   d.db,
-			tx:   tx,
-			node: n,
+			tx: nodeTx,
 		}
 		return cb(node)
 	})

autopilot/prefattach_test.go

@@ -514,18 +514,18 @@ func (d *testDBGraph) addRandChannel(node1, node2 *btcec.PublicKey,
 	return &ChannelEdge{
 			ChanID:   chanID,
 			Capacity: capacity,
-			Peer: &dbNode{
-				db:   d.db,
+			Peer: &dbNode{tx: &testNodeTx{
+				db:   d,
 				node: vertex1,
-			},
+			}},
 		},
 		&ChannelEdge{
 			ChanID:   chanID,
 			Capacity: capacity,
-			Peer: &dbNode{
-				db:   d.db,
+			Peer: &dbNode{tx: &testNodeTx{
+				db:   d,
 				node: vertex2,
-			},
+			}},
 		},
 		nil
 }
@@ -702,3 +702,37 @@ func (m *memChannelGraph) addRandNode() (*btcec.PublicKey, error) {
 
 	return newPub, nil
 }
+
+type testNodeTx struct {
+	db   *testDBGraph
+	node *models.LightningNode
+}
+
+func (t *testNodeTx) Node() *models.LightningNode {
+	return t.node
+}
+
+func (t *testNodeTx) ForEachChannel(f func(*models.ChannelEdgeInfo,
+	*models.ChannelEdgePolicy, *models.ChannelEdgePolicy) error) error {
+
+	return t.db.db.ForEachNodeChannel(t.node.PubKeyBytes, func(_ kvdb.RTx,
+		edge *models.ChannelEdgeInfo, policy1,
+		policy2 *models.ChannelEdgePolicy) error {
+
+		return f(edge, policy1, policy2)
+	})
+}
+
+func (t *testNodeTx) FetchNode(pub route.Vertex) (graphdb.NodeRTx, error) {
+	node, err := t.db.db.FetchLightningNode(pub)
+	if err != nil {
+		return nil, err
+	}
+
+	return &testNodeTx{
+		db:   t.db,
+		node: node,
+	}, nil
+}
+
+var _ graphdb.NodeRTx = (*testNodeTx)(nil)

graph/db/graph.go

@@ -588,9 +588,9 @@ func (c *ChannelGraph) FetchNodeFeatures(
 	}
 }
 
-// ForEachNodeCached is similar to ForEachNode, but it utilizes the channel
+// ForEachNodeCached is similar to forEachNode, but it utilizes the channel
 // graph cache instead. Note that this doesn't return all the information the
-// regular ForEachNode method does.
+// regular forEachNode method does.
 //
 // NOTE: The callback contents MUST not be modified.
 func (c *ChannelGraph) ForEachNodeCached(cb func(node route.Vertex,
@@ -604,7 +604,7 @@ func (c *ChannelGraph) ForEachNodeCached(cb func(node route.Vertex,
 	// We'll iterate over each node, then the set of channels for each
 	// node, and construct a similar callback functiopn signature as the
 	// main funcotin expects.
-	return c.ForEachNode(func(tx kvdb.RTx,
+	return c.forEachNode(func(tx kvdb.RTx,
 		node *models.LightningNode) error {
 
 		channels := make(map[uint64]*DirectedChannel)
@@ -716,11 +716,25 @@ func (c *ChannelGraph) DisabledChannelIDs() ([]uint64, error) {
 // ForEachNode iterates through all the stored vertices/nodes in the graph,
 // executing the passed callback with each node encountered. If the callback
 // returns an error, then the transaction is aborted and the iteration stops
+// early. Any operations performed on the NodeTx passed to the call-back are
+// executed under the same read transaction and so, methods on the NodeTx object
+// _MUST_ only be called from within the call-back.
+func (c *ChannelGraph) ForEachNode(cb func(tx NodeRTx) error) error {
+	return c.forEachNode(func(tx kvdb.RTx,
+		node *models.LightningNode) error {
+
+		return cb(newChanGraphNodeTx(tx, c, node))
+	})
+}
+
+// forEachNode iterates through all the stored vertices/nodes in the graph,
+// executing the passed callback with each node encountered. If the callback
+// returns an error, then the transaction is aborted and the iteration stops
 // early.
 //
 // TODO(roasbeef): add iterator interface to allow for memory efficient graph
 // traversal when graph gets mega
-func (c *ChannelGraph) ForEachNode(
+func (c *ChannelGraph) forEachNode(
 	cb func(kvdb.RTx, *models.LightningNode) error) error {
 
 	traversal := func(tx kvdb.RTx) error {

graph/db/graph_cache_test.go

@@ -121,7 +121,7 @@ func TestGraphCacheAddNode(t *testing.T) {
 		assertCachedPolicyEqual(t, outPolicy1, toChannels[0].InPolicy)
 
 		// Now that we've inserted two nodes into the graph, check that
-		// we'll recover the same set of channels during ForEachNode.
+		// we'll recover the same set of channels during forEachNode.
 		nodes := make(map[route.Vertex]struct{})
 		chans := make(map[uint64]struct{})
 		_ = cache.ForEachNode(func(node route.Vertex,

graph/db/graph_test.go

@@ -1092,7 +1092,7 @@ func TestGraphTraversalCacheable(t *testing.T) {
 	// Create a map of all nodes with the iteration we know works (because
 	// it is tested in another test).
 	nodeMap := make(map[route.Vertex]struct{})
-	err = graph.ForEachNode(
+	err = graph.forEachNode(
 		func(tx kvdb.RTx, n *models.LightningNode) error {
 			nodeMap[n.PubKeyBytes] = struct{}{}
 
@@ -1217,7 +1217,7 @@ func fillTestGraph(t require.TestingT, graph *ChannelGraph, numNodes,
 
 	// Iterate over each node as returned by the graph, if all nodes are
 	// reached, then the map created above should be empty.
-	err := graph.ForEachNode(
+	err := graph.forEachNode(
 		func(_ kvdb.RTx, node *models.LightningNode) error {
 			delete(nodeIndex, node.Alias)
 			return nil
@@ -1329,7 +1329,7 @@ func assertNumChans(t *testing.T, graph *ChannelGraph, n int) {
 
 func assertNumNodes(t *testing.T, graph *ChannelGraph, n int) {
 	numNodes := 0
-	err := graph.ForEachNode(
+	err := graph.forEachNode(
 		func(_ kvdb.RTx, _ *models.LightningNode) error {
 			numNodes++
 			return nil

rpcserver.go

@@ -6533,10 +6533,8 @@ func (r *rpcServer) DescribeGraph(ctx context.Context,
 	// First iterate through all the known nodes (connected or unconnected
 	// within the graph), collating their current state into the RPC
 	// response.
-	err := graph.ForEachNode(func(_ kvdb.RTx,
-		node *models.LightningNode) error {
-
-		lnNode := marshalNode(node)
+	err := graph.ForEachNode(func(nodeTx graphdb.NodeRTx) error {
+		lnNode := marshalNode(nodeTx.Node())
 
 		resp.Nodes = append(resp.Nodes, lnNode)