lnd/cmd/lncli/commands.go

package main

import (
	"bytes"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"

	"github.com/BitfuryLightning/tools/prefix_tree"
	"github.com/BitfuryLightning/tools/rt"
	"github.com/BitfuryLightning/tools/rt/graph"
	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/roasbeef/btcd/wire"
	"github.com/urfave/cli"
	"golang.org/x/net/context"

	"github.com/BitfuryLightning/tools/rt/visualizer"
)

// TODO(roasbeef): cli logic for supporting both positional and unix style
// arguments.

func printRespJson(resp interface{}) {
	b, err := json.Marshal(resp)
	if err != nil {
		fatal(err)
	}

	// TODO(roasbeef): disable 'omitempty' like behavior

	var out bytes.Buffer
	json.Indent(&out, b, "", "\t")
	out.WriteTo(os.Stdout)
}

var ShellCommand = cli.Command{
	Name:  "shell",
	Usage: "enter interactive shell",
	Action: func(c *cli.Context) {
		println("not implemented yet")
	},
}

var NewAddressCommand = cli.Command{
	Name:   "newaddress",
	Usage:  "generates a new address. Three address types are supported: p2wkh, np2wkh, p2pkh",
	Action: newAddress,
}

func newAddress(ctx *cli.Context) error {
	client := getClient(ctx)

	stringAddrType := ctx.Args().Get(0)

	// Map the string encoded address type, to the concrete typed address
	// type enum. An unrecognized address type will result in an error.
	var addrType lnrpc.NewAddressRequest_AddressType
	switch stringAddrType { // TODO(roasbeef): make them ints on the cli?
	case "p2wkh":
		addrType = lnrpc.NewAddressRequest_WITNESS_PUBKEY_HASH
	case "np2wkh":
		addrType = lnrpc.NewAddressRequest_NESTED_PUBKEY_HASH
	case "p2pkh":
		addrType = lnrpc.NewAddressRequest_PUBKEY_HASH
	default:
		return fmt.Errorf("invalid address type %v, support address type "+
			"are: p2wkh, np2wkh, p2pkh", stringAddrType)
	}

	ctxb := context.Background()
	addr, err := client.NewAddress(ctxb, &lnrpc.NewAddressRequest{
		Type: addrType,
	})
	if err != nil {
		return err
	}

	printRespJson(addr)
	return nil
}

var SendCoinsCommand = cli.Command{
	Name:        "sendcoins",
	Description: "send a specified amount of bitcoin to the passed address",
	Usage:       "sendcoins --addr=<bitcoin addresss> --amt=<num coins in satoshis>",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:  "addr",
			Usage: "the bitcoin address to send coins to on-chain",
		},
		// TODO(roasbeef): switch to BTC on command line? int may not be sufficient
		cli.IntFlag{
			Name:  "amt",
			Usage: "the number of bitcoin denominated in satoshis to send",
		},
	},
	Action: sendCoins,
}

func sendCoins(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	req := &lnrpc.SendCoinsRequest{
		Addr:   ctx.String("addr"),
		Amount: int64(ctx.Int("amt")),
	}
	txid, err := client.SendCoins(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(txid)
	return nil
}

var SendManyCommand = cli.Command{
	Name: "sendmany",
	Description: "create and broadcast a transaction paying the specified " +
		"amount(s) to the passed address(es)",
	Usage:  `sendmany '{"ExampleAddr": NumCoinsInSatoshis, "SecondAddr": NumCoins}'`,
	Action: sendMany,
}

func sendMany(ctx *cli.Context) error {
	var amountToAddr map[string]int64

	jsonMap := ctx.Args().Get(0)
	if err := json.Unmarshal([]byte(jsonMap), &amountToAddr); err != nil {
		return err
	}

	ctxb := context.Background()
	client := getClient(ctx)

	txid, err := client.SendMany(ctxb, &lnrpc.SendManyRequest{amountToAddr})
	if err != nil {
		return err
	}

	printRespJson(txid)
	return nil
}

var ConnectCommand = cli.Command{
	Name:   "connect",
	Usage:  "connect to a remote lnd peer: <lnid>@host",
	Action: connectPeer,
}

func connectPeer(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	targetAddress := ctx.Args().Get(0)
	splitAddr := strings.Split(targetAddress, "@")
	if len(splitAddr) != 2 {
		return fmt.Errorf("target address expected in format: lnid@host:port")
	}

	addr := &lnrpc.LightningAddress{
		PubKeyHash: splitAddr[0],
		Host:       splitAddr[1],
	}
	req := &lnrpc.ConnectPeerRequest{addr}

	lnid, err := client.ConnectPeer(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(lnid)
	return nil
}

// TODO(roasbeef): default number of confirmations
var OpenChannelCommand = cli.Command{
	Name: "openchannel",
	Description: "Attempt to open a new channel to an existing peer, " +
		"optionally blocking until the channel is 'open'. Once the " +
		"channel is open, a channelPoint (txid:vout) of the funding " +
		"output is returned. NOTE: peer_id and lightning_id are " +
		"mutually exclusive, only one should be used, not both.",
	Usage: "openchannel --peer_id=X --local_amt=N --remote_amt=N --num_confs=N",
	Flags: []cli.Flag{
		cli.IntFlag{
			Name:  "peer_id",
			Usage: "the relative id of the peer to open a channel with",
		},
		cli.StringFlag{
			Name:  "lightning_id",
			Usage: "the lightning id of the target peer",
		},
		cli.IntFlag{
			Name:  "local_amt",
			Usage: "the number of satoshis the wallet should commit to the channel",
		},
		cli.IntFlag{
			Name:  "remote_amt",
			Usage: "the number of satoshis the remote peer should commit to the channel",
		},
		cli.IntFlag{
			Name: "num_confs",
			Usage: "the number of confirmations required before the " +
				"channel is considered 'open'",
		},
		cli.BoolFlag{
			Name:  "block",
			Usage: "block and wait until the channel is fully open",
		},
	},
	Action: openChannel,
}

func openChannel(ctx *cli.Context) error {
	// TODO(roasbeef): add deadline to context
	ctxb := context.Background()
	client := getClient(ctx)

	if ctx.Int("peer_id") != 0 && ctx.String("lightning_id") != "" {
		return fmt.Errorf("both peer_id and lightning_id cannot be set " +
			"at the same time, only one can be specified")
	}

	req := &lnrpc.OpenChannelRequest{
		LocalFundingAmount:  int64(ctx.Int("local_amt")),
		RemoteFundingAmount: int64(ctx.Int("remote_amt")),
		NumConfs:            uint32(ctx.Int("num_confs")),
	}

	if ctx.Int("peer_id") != 0 {
		req.TargetPeerId = int32(ctx.Int("peer_id"))
	} else {
		lnID, err := hex.DecodeString(ctx.String("lightning_id"))
		if err != nil {
			return fmt.Errorf("unable to decode lightning id: %v", err)
		}
		req.TargetNode = lnID
	}

	stream, err := client.OpenChannel(ctxb, req)
	if err != nil {
		return err
	}

	if !ctx.Bool("block") {
		return nil
	}

	for {
		resp, err := stream.Recv()
		if err == io.EOF {
			return nil
		} else if err != nil {
			return err
		}

		switch update := resp.Update.(type) {
		case *lnrpc.OpenStatusUpdate_ChanOpen:
			channelPoint := update.ChanOpen.ChannelPoint
			txid, err := wire.NewShaHash(channelPoint.FundingTxid)
			if err != nil {
				return err
			}

			index := channelPoint.OutputIndex
			printRespJson(struct {
				ChannelPoint string `json:"channel_point"`
			}{
				ChannelPoint: fmt.Sprintf("%v:%v", txid, index),
			},
			)
		}
	}

	return nil
}

// TODO(roasbeef): also allow short relative channel ID.
var CloseChannelCommand = cli.Command{
	Name: "closechannel",
	Description: "Close an existing channel. The channel can be closed either " +
		"cooperatively, or uncooperatively (forced).",
	Usage: "closechannel funding_txid output_index time_limit allow_force",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:  "funding_txid",
			Usage: "the txid of the channel's funding transaction",
		},
		cli.IntFlag{
			Name: "output_index",
			Usage: "the output index for the funding output of the funding " +
				"transaction",
		},
		cli.StringFlag{
			Name: "time_limit",
			Usage: "a relative deadline afterwhich the attempt should be " +
				"abandonded",
		},
		cli.BoolFlag{
			Name: "force",
			Usage: "after the time limit has passed, attempt an " +
				"uncooperative closure",
		},
		cli.BoolFlag{
			Name:  "block",
			Usage: "block until the channel is closed",
		},
	},
	Action: closeChannel,
}

func closeChannel(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	txid, err := wire.NewShaHashFromStr(ctx.String("funding_txid"))
	if err != nil {
		return err
	}

	// TODO(roasbeef): implement time deadline within server
	req := &lnrpc.CloseChannelRequest{
		ChannelPoint: &lnrpc.ChannelPoint{
			FundingTxid: txid[:],
			OutputIndex: uint32(ctx.Int("output_index")),
		},
		Force: ctx.Bool("force"),
	}

	stream, err := client.CloseChannel(ctxb, req)
	if err != nil {
		return err
	}

	if !ctx.Bool("block") {
		return nil
	}

	for {
		resp, err := stream.Recv()
		if err == io.EOF {
			return nil
		} else if err != nil {
			return err
		}

		switch update := resp.Update.(type) {
		case *lnrpc.CloseStatusUpdate_ChanClose:
			closingHash := update.ChanClose.ClosingTxid
			txid, err := wire.NewShaHash(closingHash)
			if err != nil {
				return err
			}

			printRespJson(struct {
				ClosingTXID string `json:"closing_txid"`
			}{
				ClosingTXID: txid.String(),
			})
		}

	}

	return nil
}

var ListPeersCommand = cli.Command{
	Name:        "listpeers",
	Description: "List all active, currently connected peers.",
	Action:      listPeers,
}

func listPeers(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	req := &lnrpc.ListPeersRequest{}
	resp, err := client.ListPeers(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(resp)
	return nil
}

var WalletBalanceCommand = cli.Command{
	Name:        "walletbalance",
	Description: "compute and display the wallet's current balance",
	Usage:       "walletbalance --witness_only=[true|false]",
	Flags: []cli.Flag{
		cli.BoolFlag{
			Name: "witness_only",
			Usage: "if only witness outputs should be considered when " +
				"calculating the wallet's balance",
		},
	},
	Action: walletBalance,
}

func walletBalance(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	req := &lnrpc.WalletBalanceRequest{
		WitnessOnly: ctx.Bool("witness_only"),
	}
	resp, err := client.WalletBalance(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(resp)
	return nil
}

var ChannelBalanceCommand = cli.Command{
	Name:        "channelbalance",
	Description: "returns the sum of the total available channel balance across all open channels",
	Action:      channelBalance,
}

func channelBalance(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	req := &lnrpc.ChannelBalanceRequest{}
	resp, err := client.ChannelBalance(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(resp)
	return nil
}

var GetInfoCommand = cli.Command{
	Name:        "getinfo",
	Description: "returns basic information related to the active daemon",
	Action:      getInfo,
}

func getInfo(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	req := &lnrpc.GetInfoRequest{}
	resp, err := client.GetInfo(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(resp)
	return nil
}

var PendingChannelsCommand = cli.Command{
	Name:        "pendingchannels",
	Description: "display information pertaining to pending channels",
	Usage:       "pendingchannels --status=[all|opening|closing]",
	Flags: []cli.Flag{
		cli.BoolFlag{
			Name:  "open, o",
			Usage: "display the status of new pending channels",
		},
		cli.BoolFlag{
			Name:  "close, c",
			Usage: "display the status of channels being closed",
		},
		cli.BoolFlag{
			Name: "all, a",
			Usage: "display the status of channels in the " +
				"process of being opened or closed",
		},
	},
	Action: pendingChannels,
}

func pendingChannels(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	var channelStatus lnrpc.ChannelStatus
	switch {
	case ctx.Bool("all"):
		channelStatus = lnrpc.ChannelStatus_ALL
	case ctx.Bool("open"):
		channelStatus = lnrpc.ChannelStatus_OPENING
	case ctx.Bool("close"):
		channelStatus = lnrpc.ChannelStatus_CLOSING
	default:
		channelStatus = lnrpc.ChannelStatus_ALL
	}

	req := &lnrpc.PendingChannelRequest{channelStatus}
	resp, err := client.PendingChannels(ctxb, req)
	if err != nil {
		return err
	}

	printRespJson(resp)

	return nil
}

var SendPaymentCommand = cli.Command{
	Name:        "sendpayment",
	Description: "send a payment over lightning",
	Usage:       "sendpayment --dest=[node_id] --amt=[in_satoshis]",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:  "dest, d",
			Usage: "lightning address of the payment recipient",
		},
		cli.IntFlag{ // TODO(roasbeef): float64?
			Name:  "amt, a",
			Usage: "number of satoshis to send",
		},
		cli.StringFlag{
			Name:  "payment_hash, r",
			Usage: "the hash to use within the payment's HTLC",
		},
		cli.BoolFlag{
			Name: "fast, f",
			Usage: "skip the HTLC trickle logic, immediately creating a " +
				"new commitment",
		},
	},
	Action: sendPaymentCommand,
}

func sendPaymentCommand(ctx *cli.Context) error {
	client := getClient(ctx)

	destAddr, err := hex.DecodeString(ctx.String("dest"))
	if err != nil {
		return err
	}

	rHash, err := hex.DecodeString(ctx.String("payment_hash"))
	if err != nil {
		return err
	}
	if len(rHash) != 32 {
		return fmt.Errorf("payment hash must be exactly 32 bytes, is "+
			"instead %v", len(rHash))
	}

	req := &lnrpc.SendRequest{
		Dest:        destAddr,
		Amt:         int64(ctx.Int("amt")),
		PaymentHash: rHash[:],
		FastSend:    ctx.Bool("fast"),
	}

	paymentStream, err := client.SendPayment(context.Background())
	if err != nil {
		return err
	}

	if err := paymentStream.Send(req); err != nil {
		return err
	}

	resp, err := paymentStream.Recv()
	if err != nil {
		return err
	}

	paymentStream.CloseSend()

	printRespJson(resp)

	return nil
}

var AddInvoiceCommand = cli.Command{
	Name:        "addinvoice",
	Description: "add a new invoice, expressing intent for a future payment",
	Usage:       "addinvoice --memo=[note] --receipt=[sig+contract hash] --value=[in_satoshis] --preimage=[32_byte_hash]",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:  "memo",
			Usage: "an optional memo to attach along with the invoice",
		},
		cli.StringFlag{
			Name:  "receipt",
			Usage: "an optional cryptographic receipt of payment",
		},
		cli.StringFlag{
			Name:  "preimage",
			Usage: "the hex-encoded preimage which will allow settling an incoming HTLC payable to this preimage",
		},
		cli.IntFlag{
			Name:  "value",
			Usage: "the value of this invoice in satoshis",
		},
	},
	Action: addInvoice,
}

func addInvoice(ctx *cli.Context) error {
	client := getClient(ctx)

	preimage, err := hex.DecodeString(ctx.String("preimage"))
	if err != nil {
		return fmt.Errorf("unable to parse preimage: %v", err)
	}

	receipt, err := hex.DecodeString(ctx.String("receipt"))
	if err != nil {
		return fmt.Errorf("unable to parse receipt: %v", err)
	}

	invoice := &lnrpc.Invoice{
		Memo:      ctx.String("memo"),
		Receipt:   receipt,
		RPreimage: preimage,
		Value:     int64(ctx.Int("value")),
	}

	resp, err := client.AddInvoice(context.Background(), invoice)
	if err != nil {
		return err
	}

	printRespJson(struct {
		RHash string `json:"r_hash"`
	}{
		RHash: hex.EncodeToString(resp.RHash),
	})

	return nil
}

var LookupInvoiceCommand = cli.Command{
	Name:        "lookupinvoice",
	Description: "lookup an existing invoice by its payment hash",
	Usage:       "lookupinvoice --rhash=[32_byte_hash]",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name: "rhash",
			Usage: "the payment hash of the invoice to query for, the hash " +
				"should be a hex-encoded string",
		},
	},
	Action: lookupInvoice,
}

func lookupInvoice(ctx *cli.Context) error {
	client := getClient(ctx)

	rHash, err := hex.DecodeString(ctx.String("rhash"))
	if err != nil {
		return err
	}

	req := &lnrpc.PaymentHash{
		RHash: rHash,
	}

	invoice, err := client.LookupInvoice(context.Background(), req)
	if err != nil {
		return err
	}

	printRespJson(invoice)

	return nil
}

var ListInvoicesCommand = cli.Command{
	Name:        "listinvoices",
	Usage:       "listinvoice --pending_only=[true|false]",
	Description: "list all invoices currently stored",
	Flags: []cli.Flag{
		cli.BoolFlag{
			Name: "pending_only",
			Usage: "toggles if all invoices should be returned, or only " +
				"those that are currently unsettled",
		},
	},
	Action: listInvoices,
}

func listInvoices(ctx *cli.Context) error {
	client := getClient(ctx)

	pendingOnly := true
	if !ctx.Bool("pending_only") {
		pendingOnly = false
	}

	req := &lnrpc.ListInvoiceRequest{
		PendingOnly: pendingOnly,
	}

	invoices, err := client.ListInvoices(context.Background(), req)
	if err != nil {
		return err
	}

	printRespJson(invoices)

	return nil
}

var ShowRoutingTableCommand = cli.Command{
	Name:        "showroutingtable",
	Description: "shows routing table for a node",
	Usage:       "showroutingtable text|image",
	Subcommands: []cli.Command{
		{
			Name:        "text",
			Usage:       "[--table|--human]",
			Description: "Show routing table in textual format. By default in JSON",
			Flags: []cli.Flag{
				cli.BoolFlag{
					Name:  "table",
					Usage: "Print channels in routing table in table format.",
				},
				cli.BoolFlag{
					Name:  "human",
					Usage: "Print channels in routing table in table format. Output lightning_id partially - only a few first symbols which uniquelly identifies it.",
				},
			},
			Action: showRoutingTableAsText,
		},
		{
			Name:        "image",
			Usage:       "[--type <IMAGE_TYPE>] [--dest OUTPUT_FILE] [--open]",
			Description: "Create image with graphical representation of routing table",
			Flags: []cli.Flag{
				cli.StringFlag{
					Name:  "type",
					Usage: "Type of image file. Use one of: http://www.graphviz.org/content/output-formats. Usage of this option supresses textual output",
				},
				cli.StringFlag{
					Name:  "dest",
					Usage: "Specifies where to save the generated file. If don't specified use os.TempDir Usage of this option supresses textual output",
				},
				cli.BoolFlag{
					Name:  "open",
					Usage: "Open generated file automatically. Uses command line \"open\" command",
				},
			},
			Action: showRoutingTableAsImage,
		},
	},
}

func getRoutingTable(ctxb context.Context, client lnrpc.LightningClient) (*rt.RoutingTable, error) {
	req := &lnrpc.ShowRoutingTableRequest{}
	resp, err := client.ShowRoutingTable(ctxb, req)
	if err != nil {
		return nil, err
	}

	r := rt.NewRoutingTable()
	for _, channel := range resp.Channels {
		r.AddChannel(
			graph.NewID(channel.Id1),
			graph.NewID(channel.Id2),
			graph.NewEdgeID(channel.Outpoint),
			&rt.ChannelInfo{channel.Capacity, channel.Weight},
		)
	}
	return r, nil
}

func showRoutingTableAsText(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	r, err := getRoutingTable(ctxb, client)
	if err != nil {
		return err
	}

	if ctx.Bool("table") && ctx.Bool("human") {
		return fmt.Errorf("--table and --human cannot be used at the same time")
	}

	if ctx.Bool("table") {
		printRTAsTable(r, false)
	} else if ctx.Bool("human") {
		printRTAsTable(r, true)
	} else {
		printRTAsJSON(r)
	}
	return nil
}

func showRoutingTableAsImage(ctx *cli.Context) error {
	ctxb := context.Background()
	client := getClient(ctx)

	r, err := getRoutingTable(ctxb, client)
	if err != nil {
		return err
	}

	reqGetInfo := &lnrpc.GetInfoRequest{}
	respGetInfo, err := client.GetInfo(ctxb, reqGetInfo)
	if err != nil {
		return err
	}
	selfLightningId, err := hex.DecodeString(respGetInfo.LightningId)
	if err != nil {
		return err
	}

	imgType := ctx.String("type")
	imgDest := ctx.String("dest")
	if imgType == "" && imgDest == "" {
		return fmt.Errorf("One or both of --type or --dest should be specified")
	}

	tempFile, err := ioutil.TempFile("", "")
	if err != nil {
		return err
	}
	var imageFile *os.File
	// if the type is not specified explicitly parse the filename
	if imgType == "" {
		imgType = filepath.Ext(imgDest)[1:]
	}
	// if the filename is not specified explicitly use tempfile
	if imgDest == "" {
		imageFile, err = TempFileWithSuffix("", "rt_", "."+imgType)
		if err != nil {
			return err
		}
	} else {
		imageFile, err = os.Create(imgDest)
		if err != nil {
			return err
		}
	}
	if _, ok := visualizer.SupportedFormatsAsMap()[imgType]; !ok {
		fmt.Printf("Format: '%v' not recognized. Use one of: %v\n", imgType, visualizer.SupportedFormats())
		return nil
	}
	// generate description graph by dot language
	err = writeToTempFile(r, tempFile, selfLightningId)
	if err != nil {
		return err
	}
	err = writeToImageFile(tempFile, imageFile)
	if err != nil {
		return err
	}
	if ctx.Bool("open") {
		if err := visualizer.Open(imageFile); err != nil {
			return err
		}
	}
	return nil
}

func writeToTempFile(r *rt.RoutingTable, file *os.File, self []byte) error {
	slc := []graph.ID{graph.NewID(string(self))}
	viz := visualizer.New(r.G, slc, nil, nil)
	viz.ApplyToNode = func(s string) string { return hex.EncodeToString([]byte(s)) }
	viz.ApplyToEdge = func(info interface{}) string {
		if info, ok := info.(*rt.ChannelInfo); ok {
			return fmt.Sprintf(`"%v"`, info.Capacity())
		}
		return "nil"
	}
	// need to call method if plan to use shortcut, autocomplete, etc
	viz.BuildPrefixTree()
	viz.EnableShortcut(true)
	dot := viz.Draw()
	_, err := file.Write([]byte(dot))
	if err != nil {
		return err
	}
	err = file.Sync()
	if err != nil {
		return err
	}
	return nil
}

func writeToImageFile(TempFile, ImageFile *os.File) error {
	err := visualizer.Run("neato", TempFile, ImageFile)
	if err != nil {
		return err
	}
	err = TempFile.Close()
	if err != nil {
		return err
	}
	err = os.Remove(TempFile.Name())
	if err != nil {
		return err
	}
	err = ImageFile.Close()
	if err != nil {
		return err
	}
	return nil
}

// get around a bug in the standard library, add suffix param
func TempFileWithSuffix(dir, prefix, suffix string) (*os.File, error) {
	f, err := ioutil.TempFile(dir, prefix)
	if err != nil {
		return nil, err
	}
	defer os.Remove(f.Name())
	f, err = os.Create(f.Name() + suffix)
	return f, err
}

// Prints routing table in human readable table format
func printRTAsTable(r *rt.RoutingTable, humanForm bool) {
	// Minimum length of data part to which name can be shortened
	var minLen int
	var tmpl string
	var lightningIdTree, edgeIdTree prefix_tree.PrefixTree
	if humanForm {
		tmpl = "%-10v %-10v %-10v %-10v %-10v\n"
		minLen = 6
	} else {
		tmpl = "%-64v %-64v %-66v %-10v %-10v\n"
		minLen = 100
	}
	fmt.Printf(tmpl, "ID1", "ID2", "Outpoint", "Capacity", "Weight")
	channels := r.AllChannels()
	if humanForm {
		// Generate prefix tree for shortcuts
		lightningIdTree = prefix_tree.NewPrefixTree()
		for _, node := range r.Nodes() {
			lightningIdTree.Add(hex.EncodeToString([]byte(node.String())))
		}
		edgeIdTree = prefix_tree.NewPrefixTree()
		for _, channel := range channels {
			edgeIdTree.Add(channel.EdgeID.String())
		}
	}
	for _, channel := range channels {
		var source, target, edgeId string
		sourceHex := hex.EncodeToString([]byte(channel.Id1.String()))
		targetHex := hex.EncodeToString([]byte(channel.Id2.String()))
		edgeIdRaw := channel.EdgeID.String()
		if humanForm {
			source = getShortcut(lightningIdTree, sourceHex, minLen)
			target = getShortcut(lightningIdTree, targetHex, minLen)
			edgeId = getShortcut(edgeIdTree, edgeIdRaw, minLen)
		} else {
			source = sourceHex
			target = targetHex
			edgeId = edgeIdRaw
		}
		fmt.Printf(tmpl, source, target, edgeId, channel.Info.Cpt, channel.Info.Wgt)
	}
}

func getShortcut(tree prefix_tree.PrefixTree, s string, minLen int) string {
	s1, err := tree.Shortcut(s)
	if err != nil || s == s1 {
		return s
	}
	if len(s1) < minLen && minLen < len(s) {
		s1 = s[:minLen]
	}
	shortcut := fmt.Sprintf("%v...", s1)
	if len(shortcut) >= len(s) {
		shortcut = s
	}
	return shortcut
}

func printRTAsJSON(r *rt.RoutingTable) {
	type ChannelDesc struct {
		ID1      string  `json:"lightning_id1"`
		ID2      string  `json:"lightning_id2"`
		EdgeId   string  `json:"outpoint"`
		Capacity int64   `json:"capacity"`
		Weight   float64 `json:"weight"`
	}
	var channels struct {
		Channels []ChannelDesc `json:"channels"`
	}
	channelsRaw := r.AllChannels()
	channels.Channels = make([]ChannelDesc, 0, len(channelsRaw))
	for _, channelRaw := range channelsRaw {
		sourceHex := hex.EncodeToString([]byte(channelRaw.Id1.String()))
		targetHex := hex.EncodeToString([]byte(channelRaw.Id2.String()))
		channels.Channels = append(channels.Channels,
			ChannelDesc{
				ID1:      sourceHex,
				ID2:      targetHex,
				EdgeId:   channelRaw.EdgeID.String(),
				Weight:   channelRaw.Info.Weight(),
				Capacity: channelRaw.Info.Capacity(),
			},
		)
	}
	printRespJson(channels)
}