commands: add option to set the income channel on blinded path

It was made general enough to specify chained channels hops.

cmd/commands/cmd_invoice.go

@@ -4,6 +4,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"strconv"
+	"strings"
 
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/urfave/cli"
@@ -116,6 +117,11 @@ var AddInvoiceCommand = cli.Command{
 				"use on a blinded path. The flag may be " +
 				"specified multiple times.",
 		},
+		cli.StringSliceFlag{
+			Name: "blinded_path_income_channel",
+			Usage: "The chained channels ids to be used in a " +
+				"blinded path as the income hops.",
+		},
 	},
 	Action: actionDecorator(addInvoice),
 }
@@ -202,7 +208,8 @@ func parseBlindedPathCfg(ctx *cli.Context) (*lnrpc.BlindedPathConfig, error) {
 		if ctx.IsSet("min_real_blinded_hops") ||
 			ctx.IsSet("num_blinded_hops") ||
 			ctx.IsSet("max_blinded_paths") ||
-			ctx.IsSet("blinded_path_omit_node") {
+			ctx.IsSet("blinded_path_omit_node") ||
+			ctx.IsSet("blinded_path_income_channel") {
 
 			return nil, fmt.Errorf("blinded path options are " +
 				"only used if the `--blind` options is set")
@@ -238,6 +245,16 @@ func parseBlindedPathCfg(ctx *cli.Context) (*lnrpc.BlindedPathConfig, error) {
 			blindCfg.NodeOmissionList, pubKeyBytes,
 		)
 	}
+	channels := strings.Split(ctx.String("blinded_path_income_channel"), ",")
+	for _, chanId := range channels {
+		channelId, err := strconv.ParseUint(chanId, 10, 64)
+		if err != nil {
+			panic(err) // Handle this better in production code
+		}
+		blindCfg.ChannelIncomeList = append(
+			blindCfg.ChannelIncomeList, channelId,
+		)
+	}
 
 	return &blindCfg, nil
 }