added LND backend

backends/backend.go

@@ -0,0 +1,8 @@
+package backends
+
+type Backend interface {
+	Connect() error
+
+	// Value in satoshis and expiry in seconds
+	GetInvoice(description string, value int64, expiry int64) (invoice string, err error)
+}

backends/lnd.go

@@ -0,0 +1,78 @@
+package backends
+
+import (
+	"context"
+	"encoding/hex"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"io/ioutil"
+)
+
+type LND struct {
+	RPCHost      string `long:"rpchost" Description:"Host that the gRPC interface of LND is listening to"`
+	CertFile     string `long:"certfile" Description:"TLS certificate for LND gRPC and REST services"`
+	MacaroonFile string `long:"macaroonfile" Description:"Admin macaroon file for LND authentication. Set to an empty string for no macaroon"`
+
+	client lnrpc.LightningClient
+	ctx    context.Context
+}
+
+func (lnd *LND) Connect() error {
+	creds, err := credentials.NewClientTLSFromFile(lnd.CertFile, "")
+
+	if err != nil {
+		log.Error("Failed to read certificate for LND gRPC")
+
+		return err
+	}
+
+	con, err := grpc.Dial(lnd.RPCHost, grpc.WithTransportCredentials(creds))
+
+	if err != nil {
+		log.Error("Failed to connect to LND gRPC server")
+
+		return err
+	}
+
+	lnd.ctx = context.Background()
+
+	if lnd.MacaroonFile != "" {
+		macaroon, err := getMacaroon(lnd.MacaroonFile)
+
+		if macaroon == nil && err != nil {
+			log.Error("Failed to read admin macaroon file of LND")
+		}
+
+		lnd.ctx = metadata.NewOutgoingContext(lnd.ctx, macaroon)
+	}
+
+	lnd.client = lnrpc.NewLightningClient(con)
+
+	return err
+}
+
+func getMacaroon(macaroonFile string) (macaroon metadata.MD, err error) {
+	data, err := ioutil.ReadFile(macaroonFile)
+
+	if err == nil {
+		macaroon = metadata.Pairs("macaroon", hex.EncodeToString(data))
+	}
+
+	return macaroon, err
+}
+
+func (lnd *LND) GetInvoice(description string, value int64, expiry int64) (invoice string, err error) {
+	response, err := lnd.client.AddInvoice(lnd.ctx, &lnrpc.Invoice{
+		Memo:   description,
+		Value:  value,
+		Expiry: expiry,
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	return response.PaymentRequest, err
+}

backends/log.go

@@ -0,0 +1,9 @@
+package backends
+
+import "github.com/op/go-logging"
+
+var log logging.Logger
+
+func UseLogger(logger logging.Logger) {
+	log = logger
+}

config.go

@@ -2,7 +2,11 @@ package main
 
 import (
 	"github.com/jessevdk/go-flags"
+	"github.com/michael1011/lightningtip/backends"
 	"github.com/op/go-logging"
+	"os/user"
+	"path"
+	"runtime"
 	"strings"
 )
 
@@ -11,23 +15,40 @@ const (
 
 	defaultLogFile  = "lightningTip.log"
 	defaultLogLevel = "debug"
+
+	defaultLndRPCHost   = "localhost:10009"
+	defaultLndCertFile  = "tls.cert"
+	defaultMacaroonFile = "admin.macaroon"
 )
 
 type config struct {
-	ConfigFile string `long:"config"  Description:"Config file location"`
+	ConfigFile string `long:"config" Description:"Config file location"`
 
 	LogFile  string `long:"logfile" Description:"Log file location"`
 	LogLevel string `long:"loglevel" Description:"Log level: debug, info, warning, error"`
+
+	LND *backends.LND `group:"LND" namespace:"lnd"`
 }
 
 var cfg config
 
+var backend backends.Backend
+var backendName string
+
 func initConfig() {
+	lndDir := getDefaultLndDir()
+
 	cfg = config{
 		ConfigFile: defaultConfigFile,
 
 		LogFile:  defaultLogFile,
 		LogLevel: defaultLogLevel,
+
+		LND: &backends.LND{
+			RPCHost:      defaultLndRPCHost,
+			CertFile:     path.Join(lndDir, defaultLndCertFile),
+			MacaroonFile: path.Join(lndDir, defaultMacaroonFile),
+		},
 	}
 
 	_, err := flags.Parse(&cfg)
@@ -58,7 +79,30 @@ func initConfig() {
 	}
 
 	if errFile != nil {
-		log.Infof("Could not parse config file: %v", errFile)
+		log.Infof("Failed to parse config file: %v", errFile)
 	}
 
+	// TODO: add more backend options like for example c-lighting
+	backend = cfg.LND
+	backendName = "LND"
+}
+
+func getDefaultLndDir() (dir string) {
+	usr, err := user.Current()
+
+	if err == nil {
+		switch runtime.GOOS {
+		case "windows":
+			dir = path.Join(usr.HomeDir, "AppData/Local/Lnd")
+
+		case "darwin":
+			dir = path.Join(usr.HomeDir, "Library/Application Support/Lnd/tls.cert")
+
+		default:
+			dir = path.Join(usr.HomeDir, ".lnd")
+		}
+
+	}
+
+	return dir
 }

lightningtip.go

@@ -1,7 +1,21 @@
 package main
 
+import "fmt"
+
 func main() {
 	initLog()
 
 	initConfig()
+
+	err := backend.Connect()
+
+	if err == nil {
+		log.Info("Successfully connected to " + backendName)
+
+		invoice, err := backend.GetInvoice("Just a test", 1, 3600)
+
+		log.Info("Got invoice " + invoice)
+		log.Info(fmt.Sprint(err))
+	}
+
 }