sweep: log tx label in GetSweepFee methods

Added argument 'label' to GetSweepFee and GetSweepFeeDetails. It is logged
together with expected weight, fee and feerate.

client.go

@@ -570,8 +570,11 @@ func (s *Client) getLoopOutSweepFee(ctx context.Context, confTarget int32) (
 		htlc = swap.QuoteHtlcP2WSH
 	}
 
+	label := "loopout-quote"
+
 	return s.sweeper.GetSweepFee(
 		ctx, htlc.AddSuccessToEstimator, p2wshAddress, confTarget,
+		label,
 	)
 }
 

loopd/log.go

@@ -11,6 +11,7 @@ import (
 	"github.com/lightninglabs/loop/liquidity"
 	"github.com/lightninglabs/loop/loopdb"
 	"github.com/lightninglabs/loop/notifications"
+	"github.com/lightninglabs/loop/sweep"
 	"github.com/lightninglabs/loop/sweepbatcher"
 	"github.com/lightningnetwork/lnd"
 	"github.com/lightningnetwork/lnd/build"
@@ -52,6 +53,9 @@ func SetupLoggers(root *build.RotatingLogWriter, intercept signal.Interceptor) {
 	lnd.AddSubLogger(
 		root, notifications.Subsystem, intercept, notifications.UseLogger,
 	)
+	lnd.AddSubLogger(
+		root, sweep.Subsystem, intercept, sweep.UseLogger,
+	)
 }
 
 // genSubLogger creates a logger for a subsystem. We provide an instance of

loopin.go

@@ -1077,10 +1077,12 @@ func (s *loopInSwap) publishTimeoutTx(ctx context.Context,
 		}
 	}
 
+	label := fmt.Sprintf("loopin-timeout-%x", s.hash[:6])
+
 	// Calculate sweep tx fee.
 	fee, err := s.sweeper.GetSweepFee(
 		ctx, s.htlc.AddTimeoutToEstimator, s.timeoutAddr,
-		TimeoutTxConfTarget,
+		TimeoutTxConfTarget, label,
 	)
 	if err != nil {
 		return 0, err

loopin_test.go

@@ -312,11 +312,13 @@ func handleHtlcExpiry(t *testing.T, ctx *loopInTestContext, inSwap *loopInSwap,
 	// Expect timeout tx to be published.
 	timeoutTx := <-ctx.lnd.TxPublishChannel
 
+	label := fmt.Sprintf("loopin-timeout-%x", inSwap.hash[:6])
+
 	// We can just get our sweep fee as we would in the swap code because
 	// our estimate is static.
 	fee, err := inSwap.sweeper.GetSweepFee(
 		context.Background(), inSwap.htlc.AddTimeoutToEstimator,
-		inSwap.timeoutAddr, TimeoutTxConfTarget,
+		inSwap.timeoutAddr, TimeoutTxConfTarget, label,
 	)
 	require.NoError(t, err)
 	cost.Onchain += fee

sweep/log.go

@@ -0,0 +1,26 @@
+package sweep
+
+import (
+	"github.com/btcsuite/btclog"
+	"github.com/lightningnetwork/lnd/build"
+)
+
+// Subsystem defines the sub system name of this package.
+const Subsystem = "SWP"
+
+// log is a logger that is initialized with no output filters. This means the
+// package will not perform any logging by default until the caller requests
+// it.
+var log btclog.Logger
+
+// The default amount of logging is none.
+func init() {
+	UseLogger(build.NewSubLogger(Subsystem, nil))
+}
+
+// UseLogger uses a specified Logger to output package logging info. This
+// should be used in preference to SetLogWriter if the caller is also using
+// btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}

sweep/sweeper.go

@@ -177,15 +177,15 @@ func (s *Sweeper) CreateSweepTx(
 
 // 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
-// estimator.
+// estimator. It also takes a label used for logging.
 func (s *Sweeper) GetSweepFee(ctx context.Context,
 	addInputEstimate func(*input.TxWeightEstimator) error,
-	destAddr btcutil.Address, sweepConfTarget int32) (
+	destAddr btcutil.Address, sweepConfTarget int32, label string) (
 	btcutil.Amount, error) {
 
 	// Use GetSweepFeeDetails to get the fee and other unused data.
 	fee, _, _, err := s.GetSweepFeeDetails(
-		ctx, addInputEstimate, destAddr, sweepConfTarget,
+		ctx, addInputEstimate, destAddr, sweepConfTarget, label,
 	)
 
 	return fee, err
@@ -193,10 +193,11 @@ func (s *Sweeper) GetSweepFee(ctx context.Context,
 
 // 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.
+// estimator. It also takes a label used for logging. It returns also the fee
+// rate and transaction weight.
 func (s *Sweeper) GetSweepFeeDetails(ctx context.Context,
 	addInputEstimate func(*input.TxWeightEstimator) error,
-	destAddr btcutil.Address, sweepConfTarget int32) (
+	destAddr btcutil.Address, sweepConfTarget int32, label string) (
 	btcutil.Amount, chainfee.SatPerKWeight, lntypes.WeightUnit, error) {
 
 	// Get fee estimate from lnd.
@@ -224,7 +225,14 @@ func (s *Sweeper) GetSweepFeeDetails(ctx context.Context,
 	// Find weight.
 	weight := weightEstimate.Weight()
 
-	return feeRate.FeeForWeight(weight), feeRate, weight, nil
+	// Find fee.
+	fee := feeRate.FeeForWeight(weight)
+
+	log.Debugf("Estimations for a tx (label=%s): weight=%v, fee=%v, "+
+		"feerate=%v, sweepConfTarget=%d.", label, weight, fee, feeRate,
+		sweepConfTarget)
+
+	return fee, feeRate, weight, nil
 }
 
 // AddOutputEstimate adds output to weight estimator.