sweepbatcher: add greedy batch selection algorithm

loopout_test.go

@@ -4,13 +4,15 @@ import (
 	"context"
 	"errors"
 	"math"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/btcsuite/btcd/blockchain"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btclog"
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightninglabs/loop/loopdb"
 	"github.com/lightninglabs/loop/sweep"
@@ -255,6 +257,11 @@ func TestCustomSweepConfTarget(t *testing.T) {
 func testCustomSweepConfTarget(t *testing.T) {
 	defer test.Guard(t)()
 
+	// Setup logger for sweepbatcher.
+	logger := btclog.NewBackend(os.Stdout).Logger("SWEEP")
+	logger.SetLevel(btclog.LevelTrace)
+	sweepbatcher.UseLogger(logger)
+
 	lnd := test.NewMockLnd()
 	ctx := test.NewContext(t, lnd)
 	server := newServerMock(lnd)

sweep/sweeper.go

@@ -191,8 +191,8 @@ func (s *Sweeper) GetSweepFee(ctx context.Context,
 	return fee, err
 }
 
-// GetSweepFee calculates the required tx fee to spend to P2WKH. It takes a
-// function that is expected to add the weight of the input to the weight
+// GetSweepFeeDetails calculates the required tx fee to spend to P2WKH. It takes
+// a function that is expected to add the weight of the input to the weight
 // estimator. It returns also the fee rate and transaction weight.
 func (s *Sweeper) GetSweepFeeDetails(ctx context.Context,
 	addInputEstimate func(*input.TxWeightEstimator) error,
@@ -207,6 +207,30 @@ func (s *Sweeper) GetSweepFeeDetails(ctx context.Context,
 
 	// Calculate weight for this tx.
 	var weightEstimate input.TxWeightEstimator
+
+	// Add output.
+	if err := AddOutputEstimate(&weightEstimate, destAddr); err != nil {
+		return 0, 0, 0, fmt.Errorf("failed to add output weight "+
+			"estimate: %w", err)
+	}
+
+	// Add input.
+	err = addInputEstimate(&weightEstimate)
+	if err != nil {
+		return 0, 0, 0, fmt.Errorf("failed to add input weight "+
+			"estimate: %w", err)
+	}
+
+	// Find weight.
+	weight := weightEstimate.Weight()
+
+	return feeRate.FeeForWeight(weight), feeRate, weight, nil
+}
+
+// AddOutputEstimate adds output to weight estimator.
+func AddOutputEstimate(weightEstimate *input.TxWeightEstimator,
+	destAddr btcutil.Address) error {
+
 	switch destAddr.(type) {
 	case *btcutil.AddressWitnessScriptHash:
 		weightEstimate.AddP2WSHOutput()
@@ -224,16 +248,8 @@ func (s *Sweeper) GetSweepFeeDetails(ctx context.Context,
 		weightEstimate.AddP2TROutput()
 
 	default:
-		return 0, 0, 0, fmt.Errorf("estimate fee: unknown address "+
-			"type %T", destAddr)
+		return fmt.Errorf("unknown address type %T", destAddr)
 	}
 
-	err = addInputEstimate(&weightEstimate)
-	if err != nil {
-		return 0, 0, 0, err
-	}
-
-	weight := weightEstimate.Weight()
-
-	return feeRate.FeeForWeight(weight), feeRate, weight, nil
+	return nil
 }