lncli: add ignore_pair flag to queryroutes

cmd/lncli/cmd_payments.go

@@ -1028,6 +1028,13 @@ var queryRoutesCommand = cli.Command{
 			Usage: "(optional) the channel id of the channel " +
 				"that must be taken to the first hop",
 		},
+		cli.StringSliceFlag{
+			Name: "ignore_pair",
+			Usage: "ignore directional node pair " +
+				"<node1>:<node2>. This flag can be specified " +
+				"multiple times if multiple node pairs are " +
+				"to be ignored",
+		},
 		timePrefFlag,
 		cltvLimitFlag,
 	},
@@ -1074,6 +1081,31 @@ func queryRoutes(ctx *cli.Context) error {
 		return err
 	}
 
+	pairs := ctx.StringSlice("ignore_pair")
+	ignoredPairs := make([]*lnrpc.NodePair, len(pairs))
+	for i, pair := range pairs {
+		nodes := strings.Split(pair, ":")
+		if len(nodes) != 2 {
+			return fmt.Errorf("invalid node pair format. " +
+				"Expected <node1 pub key>:<node2 pub key>")
+		}
+
+		node1, err := hex.DecodeString(nodes[0])
+		if err != nil {
+			return err
+		}
+
+		node2, err := hex.DecodeString(nodes[1])
+		if err != nil {
+			return err
+		}
+
+		ignoredPairs[i] = &lnrpc.NodePair{
+			From: node1,
+			To:   node2,
+		}
+	}
+
 	req := &lnrpc.QueryRoutesRequest{
 		PubKey:            dest,
 		Amt:               amt,
@@ -1083,6 +1115,7 @@ func queryRoutes(ctx *cli.Context) error {
 		CltvLimit:         uint32(ctx.Uint64(cltvLimitFlag.Name)),
 		OutgoingChanId:    ctx.Uint64("outgoing_chanid"),
 		TimePref:          ctx.Float64(timePrefFlag.Name),
+		IgnoredPairs:      ignoredPairs,
 	}
 
 	route, err := client.QueryRoutes(ctxc, req)

docs/release-notes/release-notes-0.15.1.md

@@ -25,6 +25,11 @@
   `updatechanstatus`](https://github.com/lightningnetwork/lnd/pull/6705)
   to offer a convenient way to specify the channel to be updated.
 
+* [Add `ignore_pair` flag to 
+  queryroutes](https://github.com/lightningnetwork/lnd/pull/6724) to allow a 
+  user to request that specific directional node pairs be ignored during the 
+  route search.
+
 ## Database
 
 * [Delete failed payment attempts](https://github.com/lightningnetwork/lnd/pull/6438)