multi: let ForEachChannel be a method on ChannelGraph

Having a `ForEachChannel` method on the `LightningNode` struct itself
results in a `kvdb.Backend` object needing to be stored within the
LightningNode struct. In this commit, this method is replaced with a
`ForEachNodeChannel` method on the `ChannelGraph` struct will perform
the same function without needing the db pointer to be stored within the
LightningNode. This change, the LightningNode struct more closely
represents the schema on disk.

The existing `ForEachNodeChannel` method on `ChannelGraph` is renamed to
`ForEachNodeDirectedChannel`. It performs a slightly different function
since it's call-back operates on Cached policies.

autopilot/graph.go

@@ -53,6 +53,8 @@ func ChannelGraphFromDatabase(db *channeldb.ChannelGraph) ChannelGraph {
 // channeldb.LightningNode. The wrapper method implement the autopilot.Node
 // interface.
 type dbNode struct {
+	db *channeldb.ChannelGraph
+
 	tx kvdb.RTx
 
 	node *channeldb.LightningNode
@@ -86,25 +88,30 @@ func (d dbNode) Addrs() []net.Addr {
 //
 // NOTE: Part of the autopilot.Node interface.
 func (d dbNode) ForEachChannel(cb func(ChannelEdge) error) error {
-	return d.node.ForEachChannel(d.tx, func(tx kvdb.RTx,
+	return d.db.ForEachNodeChannel(d.tx, d.node.PubKeyBytes,
-		ei *channeldb.ChannelEdgeInfo, ep, _ *channeldb.ChannelEdgePolicy) error {
+		func(tx kvdb.RTx, ei *channeldb.ChannelEdgeInfo, ep,
+			_ *channeldb.ChannelEdgePolicy) error {
 
-		// Skip channels for which no outgoing edge policy is available.
+			// Skip channels for which no outgoing edge policy is
+			// available.
 			//
-		// TODO(joostjager): Ideally the case where channels have a nil
+			// TODO(joostjager): Ideally the case where channels
-		// policy should be supported, as autopilot is not looking at
+			// have a nil policy should be supported, as autopilot
-		// the policies. For now, it is not easily possible to get a
+			// is not looking at the policies. For now, it is not
-		// reference to the other end LightningNode object without
+			// easily possible to get a reference to the other end
-		// retrieving the policy.
+			// LightningNode object without retrieving the policy.
 			if ep == nil {
 				return nil
 			}
 
 			edge := ChannelEdge{
-			ChanID:   lnwire.NewShortChanIDFromInt(ep.ChannelID),
+				ChanID: lnwire.NewShortChanIDFromInt(
+					ep.ChannelID,
+				),
 				Capacity: ei.Capacity,
 				Peer: dbNode{
 					tx:   tx,
+					db:   d.db,
 					node: ep.Node,
 				},
 			}
@@ -128,6 +135,7 @@ func (d *databaseChannelGraph) ForEachNode(cb func(Node) error) error {
 		}
 
 		node := dbNode{
+			db:   d.db,
 			tx:   tx,
 			node: n,
 		}
@@ -266,6 +274,7 @@ func (d *databaseChannelGraph) addRandChannel(node1, node2 *btcec.PublicKey,
 			ChanID:   chanID,
 			Capacity: capacity,
 			Peer: dbNode{
+				db:   d.db,
 				node: vertex1,
 			},
 		},
@@ -273,6 +282,7 @@ func (d *databaseChannelGraph) addRandChannel(node1, node2 *btcec.PublicKey,
 			ChanID:   chanID,
 			Capacity: capacity,
 			Peer: dbNode{
+				db:   d.db,
 				node: vertex2,
 			},
 		},

channeldb/graph.go

@@ -459,16 +459,14 @@ func (c *ChannelGraph) ForEachChannel(cb func(*ChannelEdgeInfo,
 	}, func() {})
 }
 
-// ForEachNodeChannel iterates through all channels of a given node, executing the
+// ForEachNodeDirectedChannel iterates through all channels of a given node,
-// passed callback with an edge info structure and the policies of each end
+// executing the passed callback on the directed edge representing the channel
-// of the channel. The first edge policy is the outgoing edge *to* the
+// and its incoming policy. If the callback returns an error, then the iteration
-// connecting node, while the second is the incoming edge *from* the
+// is halted with the error propagated back up to the caller.
-// connecting node. If the callback returns an error, then the iteration is
-// halted with the error propagated back up to the caller.
 //
 // Unknown policies are passed into the callback as nil values.
-func (c *ChannelGraph) ForEachNodeChannel(tx kvdb.RTx, node route.Vertex,
+func (c *ChannelGraph) ForEachNodeDirectedChannel(tx kvdb.RTx,
-	cb func(channel *DirectedChannel) error) error {
+	node route.Vertex, cb func(channel *DirectedChannel) error) error {
 
 	if c.graphCache != nil {
 		return c.graphCache.ForEachChannel(node, cb)
@@ -557,8 +555,9 @@ func (c *ChannelGraph) ForEachNodeCached(cb func(node route.Vertex,
 	return c.ForEachNode(func(tx kvdb.RTx, node *LightningNode) error {
 		channels := make(map[uint64]*DirectedChannel)
 
-		err := node.ForEachChannel(tx, func(tx kvdb.RTx,
+		err := c.ForEachNodeChannel(tx, node.PubKeyBytes,
-			e *ChannelEdgeInfo, p1 *ChannelEdgePolicy,
+			func(tx kvdb.RTx, e *ChannelEdgeInfo,
+				p1 *ChannelEdgePolicy,
 				p2 *ChannelEdgePolicy) error {
 
 				toNodeCallback := func() route.Vertex {
@@ -574,13 +573,16 @@ func (c *ChannelGraph) ForEachNodeCached(cb func(node route.Vertex,
 				var cachedInPolicy *CachedEdgePolicy
 				if p2 != nil {
 					cachedInPolicy := NewCachedPolicy(p2)
-				cachedInPolicy.ToNodePubKey = toNodeCallback
+					cachedInPolicy.ToNodePubKey =
-				cachedInPolicy.ToNodeFeatures = toNodeFeatures
+						toNodeCallback
+					cachedInPolicy.ToNodeFeatures =
+						toNodeFeatures
 				}
 
 				directedChannel := &DirectedChannel{
 					ChannelID: e.ChannelID,
-				IsNode1:      node.PubKeyBytes == e.NodeKey1Bytes,
+					IsNode1: node.PubKeyBytes ==
+						e.NodeKey1Bytes,
 					OtherNode:    e.NodeKey2Bytes,
 					Capacity:     e.Capacity,
 					OutPolicySet: p1 != nil,
@@ -588,7 +590,8 @@ func (c *ChannelGraph) ForEachNodeCached(cb func(node route.Vertex,
 				}
 
 				if node.PubKeyBytes == e.NodeKey2Bytes {
-				directedChannel.OtherNode = e.NodeKey1Bytes
+					directedChannel.OtherNode =
+						e.NodeKey1Bytes
 				}
 
 				channels[e.ChannelID] = directedChannel
@@ -2740,15 +2743,18 @@ func (l *LightningNode) NodeAnnouncement(signed bool) (*lnwire.NodeAnnouncement,
 // isPublic determines whether the node is seen as public within the graph from
 // the source node's point of view. An existing database transaction can also be
 // specified.
-func (l *LightningNode) isPublic(tx kvdb.RTx, sourcePubKey []byte) (bool, error) {
+func (c *ChannelGraph) isPublic(tx kvdb.RTx, nodePub route.Vertex,
+	sourcePubKey []byte) (bool, error) {
+
 	// In order to determine whether this node is publicly advertised within
 	// the graph, we'll need to look at all of its edges and check whether
 	// they extend to any other node than the source node. errDone will be
 	// used to terminate the check early.
 	nodeIsPublic := false
 	errDone := errors.New("done")
-	err := l.ForEachChannel(tx, func(_ kvdb.RTx, info *ChannelEdgeInfo,
+	err := c.ForEachNodeChannel(tx, nodePub, func(tx kvdb.RTx,
-		_, _ *ChannelEdgePolicy) error {
+		info *ChannelEdgeInfo, _ *ChannelEdgePolicy,
+		_ *ChannelEdgePolicy) error {
 
 		// If this edge doesn't extend to the source node, we'll
 		// terminate our search as we can now conclude that the node is
@@ -3003,10 +3009,10 @@ func nodeTraversal(tx kvdb.RTx, nodePub []byte, db kvdb.Backend,
 	return traversal(tx)
 }
 
-// ForEachChannel iterates through all channels of this node, executing the
+// ForEachNodeChannel iterates through all channels of the given node,
-// passed callback with an edge info structure and the policies of each end
+// executing the passed callback with an edge info structure and the policies
-// of the channel. The first edge policy is the outgoing edge *to* the
+// of each end of the channel. The first edge policy is the outgoing edge *to*
-// connecting node, while the second is the incoming edge *from* the
+// the connecting node, while the second is the incoming edge *from* the
 // connecting node. If the callback returns an error, then the iteration is
 // halted with the error propagated back up to the caller.
 //
@@ -3016,14 +3022,11 @@ func nodeTraversal(tx kvdb.RTx, nodePub []byte, db kvdb.Backend,
 // should be passed as the first argument.  Otherwise the first argument should
 // be nil and a fresh transaction will be created to execute the graph
 // traversal.
-func (l *LightningNode) ForEachChannel(tx kvdb.RTx,
+func (c *ChannelGraph) ForEachNodeChannel(tx kvdb.RTx, nodePub route.Vertex,
 	cb func(kvdb.RTx, *ChannelEdgeInfo, *ChannelEdgePolicy,
 		*ChannelEdgePolicy) error) error {
 
-	nodePub := l.PubKeyBytes[:]
+	return nodeTraversal(tx, nodePub[:], c.db, cb)
-	db := l.db
-
-	return nodeTraversal(tx, nodePub, db, cb)
 }
 
 // ChannelEdgeInfo represents a fully authenticated channel along with all its
@@ -3718,7 +3721,7 @@ func (c *ChannelGraph) IsPublicNode(pubKey [33]byte) (bool, error) {
 			return err
 		}
 
-		nodeIsPublic, err = node.isPublic(tx, ourPubKey)
+		nodeIsPublic, err = c.isPublic(tx, node.PubKeyBytes, ourPubKey)
 		return err
 	}, func() {
 		nodeIsPublic = false

channeldb/graph_test.go

@@ -1056,24 +1056,33 @@ func TestGraphTraversal(t *testing.T) {
 	// outgoing channels for a particular node.
 	numNodeChans := 0
 	firstNode, secondNode := nodeList[0], nodeList[1]
-	err = firstNode.ForEachChannel(nil, func(_ kvdb.RTx, _ *ChannelEdgeInfo,
+	err = graph.ForEachNodeChannel(nil, firstNode.PubKeyBytes,
-		outEdge, inEdge *ChannelEdgePolicy) error {
+		func(_ kvdb.RTx, _ *ChannelEdgeInfo, outEdge,
+			inEdge *ChannelEdgePolicy) error {
 
-		// All channels between first and second node should have fully
+			// All channels between first and second node should
-		// (both sides) specified policies.
+			// have fully (both sides) specified policies.
 			if inEdge == nil || outEdge == nil {
 				return fmt.Errorf("channel policy not present")
 			}
 
 			// Each should indicate that it's outgoing (pointed
 			// towards the second node).
-		if !bytes.Equal(outEdge.Node.PubKeyBytes[:], secondNode.PubKeyBytes[:]) {
+			if !bytes.Equal(
+				outEdge.Node.PubKeyBytes[:],
+				secondNode.PubKeyBytes[:],
+			) {
+
 				return fmt.Errorf("wrong outgoing edge")
 			}
 
-		// The incoming edge should also indicate that it's pointing to
+			// The incoming edge should also indicate that it's
-		// the origin node.
+			// pointing to the origin node.
-		if !bytes.Equal(inEdge.Node.PubKeyBytes[:], firstNode.PubKeyBytes[:]) {
+			if !bytes.Equal(
+				inEdge.Node.PubKeyBytes[:],
+				firstNode.PubKeyBytes[:],
+			) {
+
 				return fmt.Errorf("wrong outgoing edge")
 			}
 
@@ -2280,8 +2289,9 @@ func TestIncompleteChannelPolicies(t *testing.T) {
 	// Ensure that channel is reported with unknown policies.
 	checkPolicies := func(node *LightningNode, expectedIn, expectedOut bool) {
 		calls := 0
-		err := node.ForEachChannel(nil, func(_ kvdb.RTx, _ *ChannelEdgeInfo,
+		err := graph.ForEachNodeChannel(nil, node.PubKeyBytes,
-			outEdge, inEdge *ChannelEdgePolicy) error {
+			func(_ kvdb.RTx, _ *ChannelEdgeInfo, outEdge,
+				inEdge *ChannelEdgePolicy) error {
 
 				if !expectedOut && outEdge != nil {
 					t.Fatalf("Expected no outgoing policy")
@@ -3470,8 +3480,8 @@ func BenchmarkForEachChannel(b *testing.B) {
 	}
 }
 
-// TestGraphCacheForEachNodeChannel tests that the ForEachNodeChannel method
+// TestGraphCacheForEachNodeChannel tests that the ForEachNodeDirectedChannel
-// works as expected, and is able to handle nil self edges.
+// method works as expected, and is able to handle nil self edges.
 func TestGraphCacheForEachNodeChannel(t *testing.T) {
 	graph, err := MakeTestGraph(t)
 	require.NoError(t, err)
@@ -3498,11 +3508,13 @@ func TestGraphCacheForEachNodeChannel(t *testing.T) {
 	// We should be able to accumulate the single channel added, even
 	// though we have a nil edge policy here.
 	var numChans int
-	err = graph.ForEachNodeChannel(nil, node1.PubKeyBytes,
+	err = graph.ForEachNodeDirectedChannel(nil, node1.PubKeyBytes,
-		func(channel *DirectedChannel) error {
+		func(_ *DirectedChannel) error {
 			numChans++
+
 			return nil
-		})
+		},
+	)
 	require.NoError(t, err)
 
 	require.Equal(t, numChans, 1)

routing/graph.go

@@ -75,7 +75,7 @@ func (g *CachedGraph) Close() error {
 func (g *CachedGraph) forEachNodeChannel(nodePub route.Vertex,
 	cb func(channel *channeldb.DirectedChannel) error) error {
 
-	return g.graph.ForEachNodeChannel(g.tx, nodePub, cb)
+	return g.graph.ForEachNodeDirectedChannel(g.tx, nodePub, cb)
 }
 
 // sourceNode returns the source node of the graph.

routing/router.go

@@ -2824,16 +2824,19 @@ func (r *ChannelRouter) ForEachNode(
 func (r *ChannelRouter) ForAllOutgoingChannels(cb func(kvdb.RTx,
 	*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy) error) error {
 
-	return r.selfNode.ForEachChannel(nil, func(tx kvdb.RTx,
+	return r.cfg.Graph.ForEachNodeChannel(nil, r.selfNode.PubKeyBytes,
-		c *channeldb.ChannelEdgeInfo,
+		func(tx kvdb.RTx, c *channeldb.ChannelEdgeInfo,
-		e, _ *channeldb.ChannelEdgePolicy) error {
+			e *channeldb.ChannelEdgePolicy,
+			_ *channeldb.ChannelEdgePolicy) error {
 
 			if e == nil {
-			return fmt.Errorf("channel from self node has no policy")
+				return fmt.Errorf("channel from self node " +
+					"has no policy")
 			}
 
 			return cb(tx, c, e)
-	})
+		},
+	)
 }
 
 // AddProof updates the channel edge info with proof which is needed to

rpcserver.go

@@ -6151,18 +6151,19 @@ func (r *rpcServer) GetNodeInfo(ctx context.Context,
 		channels      []*lnrpc.ChannelEdge
 	)
 
-	if err := node.ForEachChannel(nil, func(_ kvdb.RTx,
+	err = graph.ForEachNodeChannel(nil, node.PubKeyBytes,
-		edge *channeldb.ChannelEdgeInfo,
+		func(_ kvdb.RTx, edge *channeldb.ChannelEdgeInfo,
 			c1, c2 *channeldb.ChannelEdgePolicy) error {
 
 			numChannels++
 			totalCapacity += edge.Capacity
 
-		// Only populate the node's channels if the user requested them.
+			// Only populate the node's channels if the user
+			// requested them.
 			if in.IncludeChannels {
 				// Do not include unannounced channels - private
-			// channels or public channels whose authentication
+				// channels or public channels whose
-			// proof were not confirmed yet.
+				// authentication proof were not confirmed yet.
 				if edge.AuthProof == nil {
 					return nil
 				}
@@ -6174,7 +6175,9 @@ func (r *rpcServer) GetNodeInfo(ctx context.Context,
 			}
 
 			return nil
-	}); err != nil {
+		},
+	)
+	if err != nil {
 		return nil, err
 	}
 
@@ -6763,24 +6766,28 @@ func (r *rpcServer) FeeReport(ctx context.Context,
 	}
 
 	var feeReports []*lnrpc.ChannelFeeReport
-	err = selfNode.ForEachChannel(nil, func(_ kvdb.RTx, chanInfo *channeldb.ChannelEdgeInfo,
+	err = channelGraph.ForEachNodeChannel(nil, selfNode.PubKeyBytes,
+		func(_ kvdb.RTx, chanInfo *channeldb.ChannelEdgeInfo,
 			edgePolicy, _ *channeldb.ChannelEdgePolicy) error {
 
-		// Self node should always have policies for its channels.
+			// Self node should always have policies for its
+			// channels.
 			if edgePolicy == nil {
-			return fmt.Errorf("no policy for outgoing channel %v ",
+				return fmt.Errorf("no policy for outgoing "+
-				chanInfo.ChannelID)
+					"channel %v ", chanInfo.ChannelID)
 			}
 
-		// We'll compute the effective fee rate by converting from a
+			// We'll compute the effective fee rate by converting
-		// fixed point fee rate to a floating point fee rate. The fee
+			// from a fixed point fee rate to a floating point fee
-		// rate field in the database the amount of mSAT charged per
+			// rate. The fee rate field in the database the amount
-		// 1mil mSAT sent, so will divide by this to get the proper fee
+			// of mSAT charged per 1mil mSAT sent, so will divide by
-		// rate.
+			// this to get the proper fee rate.
-		feeRateFixedPoint := edgePolicy.FeeProportionalMillionths
+			feeRateFixedPoint :=
+				edgePolicy.FeeProportionalMillionths
 			feeRate := float64(feeRateFixedPoint) / feeBase
 
-		// TODO(roasbeef): also add stats for revenue for each channel
+			// TODO(roasbeef): also add stats for revenue for each
+			// channel
 			feeReports = append(feeReports, &lnrpc.ChannelFeeReport{
 				ChanId:       chanInfo.ChannelID,
 				ChannelPoint: chanInfo.ChannelPoint.String(),
@@ -6790,7 +6797,8 @@ func (r *rpcServer) FeeReport(ctx context.Context,
 			})
 
 			return nil
-	})
+		},
+	)
 	if err != nil {
 		return nil, err
 	}

server.go

@@ -3092,7 +3092,7 @@ func (s *server) establishPersistentConnections() error {
 	// TODO(roasbeef): instead iterate over link nodes and query graph for
 	// each of the nodes.
 	selfPub := s.identityECDH.PubKey().SerializeCompressed()
-	err = sourceNode.ForEachChannel(nil, func(
+	err = s.graphDB.ForEachNodeChannel(nil, sourceNode.PubKeyBytes, func(
 		tx kvdb.RTx,
 		chanInfo *channeldb.ChannelEdgeInfo,
 		policy, _ *channeldb.ChannelEdgePolicy) error {