fix: set max limit for swap fees (#59)

---------

Co-authored-by: José A.P <[email protected]>

flags.go

@@ -113,6 +113,10 @@ func init() {
 	rootCmd.Flags().Float64("backoffLimit", 0.1, "Limit coefficient of the backoff")
 	viper.BindPFlag("backoffLimit", rootCmd.Flags().Lookup("backoffLimit"))
 
+	// Limit fees for swaps
+	rootCmd.Flags().Float64("limitFees", 0.007, "Limit fees for swaps e.g. 0.01")
+	viper.BindPFlag("limitFees", rootCmd.Flags().Lookup("limitFees"))
+
 	//Now we set the global vars
 
 	pollingInterval = viper.GetDuration("pollingInterval")
@@ -123,6 +127,7 @@ func init() {
 	retries = viper.GetInt("retriesBeforeBackoff")
 	backoffCoefficient = viper.GetFloat64("backoffCoefficient")
 	backoffLimit = viper.GetFloat64("backoffLimit")
+	limitFees = viper.GetFloat64("limitFees")
 
 	//Set log level and format
 

liquidator.go

@@ -35,6 +35,7 @@ var (
 	retries            int
 	backoffCoefficient float64
 	backoffLimit       float64
+	limitFees          float64
 )
 
 // Entrypoint of liquidator main logic

provider/loop_provider.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"encoding/hex"
 	"fmt"
+	"os"
 	"reflect"
+	"strconv"
 	"time"
 
 	"github.com/Elenpay/liquidator/errors"
@@ -60,6 +62,16 @@ func (l *LoopProvider) RequestSubmarineSwap(ctx context.Context, request Submari
 		return SubmarineSwapResponse{}, err
 	}
 
+	limitFeesStr := os.Getenv("LIMITFEES")
+	limitFees, err := strconv.ParseFloat(limitFeesStr, 64)
+	sumFees := quote.SwapFeeSat + quote.HtlcPublishFeeSat
+
+	if sumFees > int64(float64(request.SatsAmount)*limitFees) {
+		err := fmt.Errorf("swap fees are greater than max limit fees")
+		log.Error(err)
+		return SubmarineSwapResponse{}, err
+	}
+
 	//Get limits
 	limits := getInLimits(quote)
 
@@ -219,11 +231,20 @@ func (l *LoopProvider) RequestReverseSubmarineSwap(ctx context.Context, request
 	})
 
 	if err != nil {
-
 		log.Errorf("error getting quote for reverse submarine swap: %s", err)
 		return ReverseSubmarineSwapResponse{}, err
 	}
 
+	limitFeesStr := os.Getenv("LIMITFEES")
+	limitFees, err := strconv.ParseFloat(limitFeesStr, 64)
+	sumFees := quote.SwapFeeSat + quote.HtlcSweepFeeSat + quote.PrepayAmtSat
+
+	if sumFees > int64(float64(request.SatsAmount)*limitFees) {
+		err := fmt.Errorf("swap fees are greater than max limit fees")
+		log.Error(err)
+		return ReverseSubmarineSwapResponse{}, err
+	}
+
 	//Get limits
 	//Amt using btcutil
 	amt := btcutil.Amount(request.SatsAmount)

provider/loop_provider_test.go

@@ -3,6 +3,7 @@ package provider
 import (
 	"context"
 	"encoding/hex"
+	"os"
 	"reflect"
 	"testing"
 	"time"
@@ -16,6 +17,8 @@ func TestLoopProvider_RequestSubmarineSwap(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 
+	os.Setenv("LIMITFEES", "0.1")
+
 	//Mock lightning swapClient GetLoopInQuote and LoopIn methods to return fake data
 	swapClient := NewMockSwapClientClient(ctrl)