initial commit

lightning.go

@@ -0,0 +1,131 @@
+package main
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"strconv"
+	"time"
+
+	lnrpc "github.com/lncm/lnd-rpc/v0.10.0/lnrpc"
+	routerrpc "github.com/lncm/lnd-rpc/v0.10.0/routerrpc"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+
+	"gopkg.in/macaroon.v2"
+)
+
+type rpcCreds map[string]string
+
+func (m rpcCreds) RequireTransportSecurity() bool { return true }
+func (m rpcCreds) GetRequestMetadata(_ context.Context, _ ...string) (map[string]string, error) {
+	return m, nil
+}
+func newCreds(bytes []byte) rpcCreds {
+	creds := make(map[string]string)
+	creds["macaroon"] = hex.EncodeToString(bytes)
+	return creds
+}
+
+func getRouterClient(hostname string, port int, tlsFile, macaroonFile string) routerrpc.RouterClient {
+	macaroonBytes, err := ioutil.ReadFile(macaroonFile)
+	if err != nil {
+		log.Println("Cannot read macaroon file .. ", err)
+		panic(err)
+	}
+
+	mac := &macaroon.Macaroon{}
+	if err = mac.UnmarshalBinary(macaroonBytes); err != nil {
+		log.Println("Cannot unmarshal macaroon .. ", err)
+		panic(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	transportCredentials, err := credentials.NewClientTLSFromFile(tlsFile, hostname)
+	if err != nil {
+		panic(err)
+	}
+
+	fullHostname := fmt.Sprintf("%s:%d", hostname, port)
+
+	connection, err := grpc.DialContext(ctx, fullHostname, []grpc.DialOption{
+		grpc.WithBlock(),
+		grpc.WithTransportCredentials(transportCredentials),
+		grpc.WithPerRPCCredentials(newCreds(macaroonBytes)),
+	}...)
+	if err != nil {
+		log.Printf("unable to connect to %s: %w", fullHostname, err)
+		panic(err)
+	}
+
+	return routerrpc.NewRouterClient(connection)
+}
+
+func pay_invoice(invoice string) (payment_status string, failure_reason string, return_err error) {
+
+	payment_status = ""
+	failure_reason = ""
+	return_err = nil
+
+	// SendPaymentV2
+
+	ctx2, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// get node parameters from environment variables
+
+	ln_port, err := strconv.Atoi(os.Getenv("LN_PORT"))
+	if err != nil {
+		return_err = err
+		return
+	}
+
+	r_client := getRouterClient(
+		os.Getenv("LN_HOST"),
+		ln_port,
+		os.Getenv("LN_TLS_FILE"),
+		os.Getenv("LN_MACAROON_FILE"))
+
+	fee_limit_sat_str := os.Getenv("FEE_LIMIT_SAT")
+	fee_limit_sat, err := strconv.ParseInt(fee_limit_sat_str, 10, 64)
+	if err != nil {
+		return_err = err
+		return
+	}
+
+	stream, err := r_client.SendPaymentV2(ctx2, &routerrpc.SendPaymentRequest{
+		PaymentRequest:    invoice,
+		NoInflightUpdates: true,
+		TimeoutSeconds:    30,
+		FeeLimitSat:       fee_limit_sat})
+
+	if err != nil {
+		return_err = err
+		return
+	}
+
+	for {
+		update, err := stream.Recv()
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			return_err = err
+			return
+		}
+
+		payment_status = lnrpc.Payment_PaymentStatus_name[int32(update.Status)]
+		failure_reason = lnrpc.PaymentFailureReason_name[int32(update.FailureReason)]
+	}
+
+	return
+}