lncli: remote peer alias in listchannels

cmd/lncli/commands.go

@@ -1415,6 +1415,11 @@ var listChannelsCommand = cli.Command{
 				"particular peer, accepts 66-byte, " +
 				"hex-encoded pubkeys",
 		},
+		cli.BoolFlag{
+			Name: "skip_peer_alias_lookup",
+			Usage: "skip the peer alias lookup per channel in " +
+				"order to improve performance",
+		},
 	},
 	Action: actionDecorator(listChannels),
 }
@@ -1463,12 +1468,17 @@ func listChannels(ctx *cli.Context) error {
 		peerKey = pk[:]
 	}
 
+	// By default we will look up the peers' alias information unless the
+	// skip_peer_alias_lookup flag indicates otherwise.
+	lookupPeerAlias := !ctx.Bool("skip_peer_alias_lookup")
+
 	req := &lnrpc.ListChannelsRequest{
-		ActiveOnly:   ctx.Bool("active_only"),
-		InactiveOnly: ctx.Bool("inactive_only"),
-		PublicOnly:   ctx.Bool("public_only"),
-		PrivateOnly:  ctx.Bool("private_only"),
-		Peer:         peerKey,
+		ActiveOnly:      ctx.Bool("active_only"),
+		InactiveOnly:    ctx.Bool("inactive_only"),
+		PublicOnly:      ctx.Bool("public_only"),
+		PrivateOnly:     ctx.Bool("private_only"),
+		Peer:            peerKey,
+		PeerAliasLookup: lookupPeerAlias,
 	}
 
 	resp, err := client.ListChannels(ctxc, req)

docs/release-notes/release-notes-0.16.0.md

@@ -141,6 +141,13 @@ of order is also [fixed](https://github.com/lightningnetwork/lnd/pull/7264).
   `updatenodeannouncement` peers cli which did not allow setting/
    unsetting of feature bits also has been fixed. 
 
+* [Enrich the `Channel` message with a peers' alias in order to retrieve it
+  in `ListChannels`.](https://github.com/lightningnetwork/lnd/pull/7322) This
+  behavior is opt-in for users of the rpc interface through a new parameter in
+  `ListChannelsRequest` called `PeerAliasLookup`. For users of lncli this
+  parameter is enabled by default but can be disabled with a new flag
+  `--skip_peer_alias_lookup`.
+
 ## Wallet
 
 * [Allows Taproot public keys and tap scripts to be imported as watch-only

itest/lnd_misc_test.go

@@ -272,11 +272,20 @@ func testListChannels(ht *lntest.HarnessTest) {
 	// Check the returned response is correct.
 	aliceChannel := ht.QueryChannelByChanPoint(alice, chanPoint)
 
+	// Query the channel again, this time with peer alias lookup.
+	aliceChannelWithAlias := ht.QueryChannelByChanPoint(
+		alice, chanPoint, lntest.WithPeerAliasLookup(),
+	)
+
 	// Since Alice is the initiator, she pays the commit fee.
 	aliceBalance := int64(chanAmt) - aliceChannel.CommitFee - int64(pushAmt)
 
+	bobAlias := bob.RPC.GetInfo().Alias
+
 	// Check the balance related fields are correct.
 	require.Equal(ht, aliceBalance, aliceChannel.LocalBalance)
+	require.Empty(ht, aliceChannel.PeerAlias)
+	require.Equal(ht, bobAlias, aliceChannelWithAlias.PeerAlias)
 	require.EqualValues(ht, pushAmt, aliceChannel.RemoteBalance)
 	require.EqualValues(ht, pushAmt, aliceChannel.PushAmountSat)
 
@@ -318,8 +327,17 @@ func testListChannels(ht *lntest.HarnessTest) {
 	require.Equal(ht, aliceChannel.ChannelPoint, bobChannel.ChannelPoint,
 		"Bob's channel point mismatched")
 
+	// Query the channel again, this time with node alias lookup.
+	bobChannelWithAlias := ht.QueryChannelByChanPoint(
+		bob, chanPoint, lntest.WithPeerAliasLookup(),
+	)
+
+	aliceAlias := alice.RPC.GetInfo().Alias
+
 	// Check the balance related fields are correct.
 	require.Equal(ht, aliceBalance, bobChannel.RemoteBalance)
+	require.Empty(ht, bobChannel.PeerAlias)
+	require.Equal(ht, aliceAlias, bobChannelWithAlias.PeerAlias)
 	require.EqualValues(ht, pushAmt, bobChannel.LocalBalance)
 	require.EqualValues(ht, pushAmt, bobChannel.PushAmountSat)
 

lnrpc/lightning.proto

@@ -1531,6 +1531,9 @@ message Channel {
 
     // This is the confirmed / on-chain zero-conf SCID.
     uint64 zero_conf_confirmed_scid = 33;
+
+    // The configured alias name of our peer.
+    string peer_alias = 34;
 }
 
 message ListChannelsRequest {
@@ -1544,6 +1547,11 @@ message ListChannelsRequest {
     empty, all channels will be returned.
     */
     bytes peer = 5;
+
+    // Informs the server if the peer alias lookup per channel should be
+    // enabled. It is turned off by default in order to avoid degradation of
+    // performance for existing clients.
+    bool peer_alias_lookup = 6;
 }
 message ListChannelsResponse {
     // The list of active channels

lnrpc/lightning.swagger.json

@@ -135,6 +135,13 @@
             "required": false,
             "type": "string",
             "format": "byte"
+          },
+          {
+            "name": "peer_alias_lookup",
+            "description": "Informs the server if the peer alias lookup per channel should be\nenabled. It is turned off by default in order to avoid degradation of\nperformance for existing clients.",
+            "in": "query",
+            "required": false,
+            "type": "boolean"
           }
         ],
         "tags": [
@@ -3556,6 +3563,10 @@
           "type": "string",
           "format": "uint64",
           "description": "This is the confirmed / on-chain zero-conf SCID."
+        },
+        "peer_alias": {
+          "type": "string",
+          "description": "The configured alias name of our peer."
         }
       }
     },

lntest/harness.go

@@ -1598,10 +1598,12 @@ func (h *HarnessTest) MineEmptyBlocks(num int) []*wire.MsgBlock {
 // QueryChannelByChanPoint tries to find a channel matching the channel point
 // and asserts. It returns the channel found.
 func (h *HarnessTest) QueryChannelByChanPoint(hn *node.HarnessNode,
-	chanPoint *lnrpc.ChannelPoint) *lnrpc.Channel {
+	chanPoint *lnrpc.ChannelPoint,
+	opts ...ListChannelOption) *lnrpc.Channel {
 
-	channel, err := h.findChannel(hn, chanPoint)
+	channel, err := h.findChannel(hn, chanPoint, opts...)
 	require.NoError(h, err, "failed to query channel")
+
 	return channel
 }
 

lntest/harness_assertion.go

@@ -31,6 +31,18 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
+// FindChannelOption is a functional type for an option that modifies a
+// ListChannelsRequest.
+type ListChannelOption func(r *lnrpc.ListChannelsRequest)
+
+// WithPeerAliasLookup is an option for setting the peer alias lookup flag on a
+// ListChannelsRequest.
+func WithPeerAliasLookup() ListChannelOption {
+	return func(r *lnrpc.ListChannelsRequest) {
+		r.PeerAliasLookup = true
+	}
+}
+
 // WaitForBlockchainSync waits until the node is synced to chain.
 func (h *HarnessTest) WaitForBlockchainSync(hn *node.HarnessNode) {
 	err := wait.NoError(func() error {
@@ -368,12 +380,18 @@ func (h *HarnessTest) AssertChannelExists(hn *node.HarnessNode,
 // findChannel tries to find a target channel in the node using the given
 // channel point.
 func (h *HarnessTest) findChannel(hn *node.HarnessNode,
-	chanPoint *lnrpc.ChannelPoint) (*lnrpc.Channel, error) {
+	chanPoint *lnrpc.ChannelPoint,
+	opts ...ListChannelOption) (*lnrpc.Channel, error) {
 
 	// Get the funding point.
 	fp := h.OutPointFromChannelPoint(chanPoint)
 
 	req := &lnrpc.ListChannelsRequest{}
+
+	for _, opt := range opts {
+		opt(req)
+	}
+
 	channelInfo := hn.RPC.ListChannels(req)
 
 	// Find the target channel.

rpcserver.go

@@ -4017,7 +4017,9 @@ func (r *rpcServer) ListChannels(ctx context.Context,
 		// Next, we'll determine whether we should add this channel to
 		// our list depending on the type of channels requested to us.
 		isActive := peerOnline && linkActive
-		channel, err := createRPCOpenChannel(r, dbChannel, isActive)
+		channel, err := createRPCOpenChannel(
+			r, dbChannel, isActive, in.PeerAliasLookup,
+		)
 		if err != nil {
 			return nil, err
 		}
@@ -4066,7 +4068,6 @@ func rpcCommitmentType(chanType channeldb.ChannelType) lnrpc.CommitmentType {
 // *Channeldb.ChannelConfig.
 func createChannelConstraint(
 	chanCfg *channeldb.ChannelConfig) *lnrpc.ChannelConstraints {
-
 	return &lnrpc.ChannelConstraints{
 		CsvDelay:          uint32(chanCfg.CsvDelay),
 		ChanReserveSat:    uint64(chanCfg.ChanReserve),
@@ -4088,7 +4089,7 @@ func isPrivate(dbChannel *channeldb.OpenChannel) bool {
 
 // createRPCOpenChannel creates an *lnrpc.Channel from the *channeldb.Channel.
 func createRPCOpenChannel(r *rpcServer, dbChannel *channeldb.OpenChannel,
-	isActive bool) (*lnrpc.Channel, error) {
+	isActive, peerAliasLookup bool) (*lnrpc.Channel, error) {
 
 	nodePub := dbChannel.IdentityPub
 	nodeID := hex.EncodeToString(nodePub.SerializeCompressed())
@@ -4164,6 +4165,16 @@ func createRPCOpenChannel(r *rpcServer, dbChannel *channeldb.OpenChannel,
 		RemoteChanReserveSat: int64(dbChannel.RemoteChanCfg.ChanReserve),
 	}
 
+	// Look up our channel peer's node alias if the caller requests it.
+	if peerAliasLookup {
+		peerAlias, err := r.server.graphDB.LookupAlias(nodePub)
+		if err != nil {
+			return nil, fmt.Errorf("unable to lookup peer "+
+				"alias: %w", err)
+		}
+		channel.PeerAlias = peerAlias
+	}
+
 	// Populate the set of aliases.
 	for _, chanAlias := range channelAliases {
 		channel.AliasScids = append(
@@ -4576,7 +4587,7 @@ func (r *rpcServer) SubscribeChannelEvents(req *lnrpc.ChannelEventSubscription,
 				}
 			case channelnotifier.OpenChannelEvent:
 				channel, err := createRPCOpenChannel(
-					r, event.Channel, true,
+					r, event.Channel, true, false,
 				)
 				if err != nil {
 					return err