Merge pull request #3440 from joostjager/buildroute

routing: add build route functionality

cmd/lncli/cmd_build_route.go

@@ -0,0 +1,94 @@
+// +build routerrpc
+
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/lightningnetwork/lnd"
+	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
+	"github.com/lightningnetwork/lnd/routing/route"
+	"github.com/urfave/cli"
+)
+
+var buildRouteCommand = cli.Command{
+	Name:     "buildroute",
+	Category: "Payments",
+	Usage:    "Build a route from a list of hop pubkeys.",
+	Action:   actionDecorator(buildRoute),
+	Flags: []cli.Flag{
+		cli.Int64Flag{
+			Name: "amt",
+			Usage: "the amount to send expressed in satoshis. If" +
+				"not set, the minimum routable amount is used",
+		},
+		cli.Int64Flag{
+			Name: "final_cltv_delta",
+			Usage: "number of blocks the last hop has to reveal " +
+				"the preimage",
+			Value: lnd.DefaultBitcoinTimeLockDelta,
+		},
+		cli.StringFlag{
+			Name:  "hops",
+			Usage: "comma separated hex pubkeys",
+		},
+		cli.Uint64Flag{
+			Name: "outgoing_chan_id",
+			Usage: "short channel id of the outgoing channel to " +
+				"use for the first hop of the payment",
+			Value: 0,
+		},
+	},
+}
+
+func buildRoute(ctx *cli.Context) error {
+	conn := getClientConn(ctx, false)
+	defer conn.Close()
+
+	client := routerrpc.NewRouterClient(conn)
+
+	if !ctx.IsSet("hops") {
+		return errors.New("hops required")
+	}
+
+	// Build list of hop addresses for the rpc.
+	hops := strings.Split(ctx.String("hops"), ",")
+	rpcHops := make([][]byte, 0, len(hops))
+	for _, k := range hops {
+		pubkey, err := route.NewVertexFromStr(k)
+		if err != nil {
+			return fmt.Errorf("error parsing %v: %v", k, err)
+		}
+		rpcHops = append(rpcHops, pubkey[:])
+	}
+
+	var amtMsat int64
+	hasAmt := ctx.IsSet("amt")
+	if hasAmt {
+		amtMsat = ctx.Int64("amt") * 1000
+		if amtMsat == 0 {
+			return fmt.Errorf("non-zero amount required")
+		}
+	}
+
+	// Call BuildRoute rpc.
+	req := &routerrpc.BuildRouteRequest{
+		AmtMsat:        amtMsat,
+		FinalCltvDelta: int32(ctx.Int64("final_cltv_delta")),
+		HopPubkeys:     rpcHops,
+		OutgoingChanId: ctx.Uint64("outgoing_chan_id"),
+	}
+
+	rpcCtx := context.Background()
+	route, err := client.BuildRoute(rpcCtx, req)
+	if err != nil {
+		return err
+	}
+
+	printJSON(route)
+
+	return nil
+}

cmd/lncli/commands.go

@@ -21,6 +21,7 @@ import (
 	"github.com/golang/protobuf/jsonpb"
 	"github.com/golang/protobuf/proto"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
 	"github.com/lightningnetwork/lnd/walletunlocker"
 	"github.com/urfave/cli"
 	"golang.org/x/crypto/ssh/terminal"
@@ -2381,22 +2382,23 @@ var sendToRouteCommand = cli.Command{
 	Usage:    "Send a payment over a predefined route.",
 	Description: `
 	Send a payment over Lightning using a specific route. One must specify
-	a list of routes to attempt and the payment hash. This command can even
-	be chained with the response to queryroutes. This command can be used
-	to implement channel rebalancing by crafting a self-route, or even
-	atomic swaps using a self-route that crosses multiple chains.
+	the route to attempt and the payment hash. This command can even
+	be chained with the response to queryroutes or buildroute. This command
+	can be used to implement channel rebalancing by crafting a self-route, 
+	or even atomic swaps using a self-route that crosses multiple chains.
 
-	There are three ways to specify routes:
+	There are three ways to specify a route:
 	   * using the --routes parameter to manually specify a JSON encoded
-	     set of routes in the format of the return value of queryroutes:
+	     route in the format of the return value of queryroutes or
+	     buildroute:
 	         (lncli sendtoroute --payment_hash=<pay_hash> --routes=<route>)
 
-	   * passing the routes as a positional argument:
+	   * passing the route as a positional argument:
 	         (lncli sendtoroute --payment_hash=pay_hash <route>)
 
-	   * or reading in the routes from stdin, which can allow chaining the
-	     response from queryroutes, or even read in a file with a set of
-	     pre-computed routes:
+	   * or reading in the route from stdin, which can allow chaining the
+	     response from queryroutes or buildroute, or even read in a file
+	     with a pre-computed route:
 	         (lncli queryroutes --args.. | lncli sendtoroute --payment_hash= -
 
 	     notice the '-' at the end, which signals that lncli should read
@@ -2474,25 +2476,37 @@ func sendToRoute(ctx *cli.Context) error {
 		jsonRoutes = string(b)
 	}
 
+	// Try to parse the provided json both in the legacy QueryRoutes format
+	// that contains a list of routes and the single route BuildRoute
+	// format.
+	var route *lnrpc.Route
 	routes := &lnrpc.QueryRoutesResponse{}
 	err = jsonpb.UnmarshalString(jsonRoutes, routes)
-	if err != nil {
-		return fmt.Errorf("unable to unmarshal json string "+
-			"from incoming array of routes: %v", err)
-	}
+	if err == nil {
+		if len(routes.Routes) == 0 {
+			return fmt.Errorf("no routes provided")
+		}
 
-	if len(routes.Routes) == 0 {
-		return fmt.Errorf("no routes provided")
-	}
+		if len(routes.Routes) != 1 {
+			return fmt.Errorf("expected a single route, but got %v",
+				len(routes.Routes))
+		}
 
-	if len(routes.Routes) != 1 {
-		return fmt.Errorf("expected a single route, but got %v",
-			len(routes.Routes))
+		route = routes.Routes[0]
+	} else {
+		routes := &routerrpc.BuildRouteResponse{}
+		err = jsonpb.UnmarshalString(jsonRoutes, routes)
+		if err != nil {
+			return fmt.Errorf("unable to unmarshal json string "+
+				"from incoming array of routes: %v", err)
+		}
+
+		route = routes.Route
 	}
 
 	req := &lnrpc.SendToRouteRequest{
 		PaymentHash: rHash,
-		Route:       routes.Routes[0],
+		Route:       route,
 	}
 
 	return sendToRouteRequest(ctx, req)

cmd/lncli/routerrpc_active.go

@@ -6,5 +6,9 @@ import "github.com/urfave/cli"
 
 // routerCommands will return nil for non-routerrpc builds.
 func routerCommands() []cli.Command {
-	return []cli.Command{queryMissionControlCommand, resetMissionControlCommand}
+	return []cli.Command{
+		queryMissionControlCommand,
+		resetMissionControlCommand,
+		buildRouteCommand,
+	}
 }