chainfee: create new chainfee package extracting fees from lnwallet

In this commit, we create a new chainfee package, that houses all fee
related functionality used within the codebase. The creation of this new
package furthers our long-term goal of extracting functionality from the
bloated `lnwallet` package into new distinct packages. Additionally,
this new packages resolves a class of import cycle that could arise if a
new package that was imported by something in `lnwallet` wanted to use
the existing fee related functions in the prior `lnwallet` package.

sweep/fee_estimator_mock_test.go

@@ -3,38 +3,38 @@ package sweep
 import (
 	"sync"
 
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 // mockFeeEstimator implements a mock fee estimator. It closely resembles
 // lnwallet.StaticFeeEstimator with the addition that fees can be changed for
 // testing purposes in a thread safe manner.
 type mockFeeEstimator struct {
-	feePerKW lnwallet.SatPerKWeight
+	feePerKW chainfee.SatPerKWeight
 
-	relayFee lnwallet.SatPerKWeight
+	relayFee chainfee.SatPerKWeight
 
-	blocksToFee map[uint32]lnwallet.SatPerKWeight
+	blocksToFee map[uint32]chainfee.SatPerKWeight
 
 	// A closure that when set is used instead of the
 	// mockFeeEstimator.EstimateFeePerKW method.
-	estimateFeePerKW func(numBlocks uint32) (lnwallet.SatPerKWeight, error)
+	estimateFeePerKW func(numBlocks uint32) (chainfee.SatPerKWeight, error)
 
 	lock sync.Mutex
 }
 
 func newMockFeeEstimator(feePerKW,
-	relayFee lnwallet.SatPerKWeight) *mockFeeEstimator {
+	relayFee chainfee.SatPerKWeight) *mockFeeEstimator {
 
 	return &mockFeeEstimator{
 		feePerKW:    feePerKW,
 		relayFee:    relayFee,
-		blocksToFee: make(map[uint32]lnwallet.SatPerKWeight),
+		blocksToFee: make(map[uint32]chainfee.SatPerKWeight),
 	}
 }
 
 func (e *mockFeeEstimator) updateFees(feePerKW,
-	relayFee lnwallet.SatPerKWeight) {
+	relayFee chainfee.SatPerKWeight) {
 
 	e.lock.Lock()
 	defer e.lock.Unlock()
@@ -44,7 +44,7 @@ func (e *mockFeeEstimator) updateFees(feePerKW,
 }
 
 func (e *mockFeeEstimator) EstimateFeePerKW(numBlocks uint32) (
-	lnwallet.SatPerKWeight, error) {
+	chainfee.SatPerKWeight, error) {
 
 	e.lock.Lock()
 	defer e.lock.Unlock()
@@ -60,7 +60,7 @@ func (e *mockFeeEstimator) EstimateFeePerKW(numBlocks uint32) (
 	return e.feePerKW, nil
 }
 
-func (e *mockFeeEstimator) RelayFeePerKW() lnwallet.SatPerKWeight {
+func (e *mockFeeEstimator) RelayFeePerKW() chainfee.SatPerKWeight {
 	e.lock.Lock()
 	defer e.lock.Unlock()
 
@@ -75,4 +75,4 @@ func (e *mockFeeEstimator) Stop() error {
 	return nil
 }
 
-var _ lnwallet.FeeEstimator = (*mockFeeEstimator)(nil)
+var _ chainfee.Estimator = (*mockFeeEstimator)(nil)

sweep/sweeper.go

@@ -16,13 +16,14 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 const (
 	// DefaultMaxFeeRate is the default maximum fee rate allowed within the
 	// UtxoSweeper. The current value is equivalent to a fee rate of 10,000
 	// sat/vbyte.
-	DefaultMaxFeeRate = lnwallet.FeePerKwFloor * 1e4
+	DefaultMaxFeeRate = chainfee.FeePerKwFloor * 1e4
 
 	// DefaultFeeRateBucketSize is the default size of fee rate buckets
 	// we'll use when clustering inputs into buckets with similar fee rates
@@ -92,7 +93,7 @@ type pendingInput struct {
 
 	// lastFeeRate is the most recent fee rate used for this input within a
 	// transaction broadcast to the network.
-	lastFeeRate lnwallet.SatPerKWeight
+	lastFeeRate chainfee.SatPerKWeight
 }
 
 // pendingInputs is a type alias for a set of pending inputs.
@@ -101,7 +102,7 @@ type pendingInputs = map[wire.OutPoint]*pendingInput
 // inputCluster is a helper struct to gather a set of pending inputs that should
 // be swept with the specified fee rate.
 type inputCluster struct {
-	sweepFeeRate lnwallet.SatPerKWeight
+	sweepFeeRate chainfee.SatPerKWeight
 	inputs       pendingInputs
 }
 
@@ -126,7 +127,7 @@ type PendingInput struct {
 
 	// LastFeeRate is the most recent fee rate used for the input being
 	// swept within a transaction broadcast to the network.
-	LastFeeRate lnwallet.SatPerKWeight
+	LastFeeRate chainfee.SatPerKWeight
 
 	// BroadcastAttempts is the number of attempts we've made to sweept the
 	// input.
@@ -182,7 +183,7 @@ type UtxoSweeper struct {
 
 	currentOutputScript []byte
 
-	relayFeeRate lnwallet.SatPerKWeight
+	relayFeeRate chainfee.SatPerKWeight
 
 	quit chan struct{}
 	wg   sync.WaitGroup
@@ -197,7 +198,7 @@ type UtxoSweeperConfig struct {
 	// FeeEstimator is used when crafting sweep transactions to estimate
 	// the necessary fee relative to the expected size of the sweep
 	// transaction.
-	FeeEstimator lnwallet.FeeEstimator
+	FeeEstimator chainfee.Estimator
 
 	// PublishTransaction facilitates the process of broadcasting a signed
 	// transaction to the appropriate network.
@@ -235,7 +236,7 @@ type UtxoSweeperConfig struct {
 
 	// MaxFeeRate is the the maximum fee rate allowed within the
 	// UtxoSweeper.
-	MaxFeeRate lnwallet.SatPerKWeight
+	MaxFeeRate chainfee.SatPerKWeight
 
 	// FeeRateBucketSize is the default size of fee rate buckets we'll use
 	// when clustering inputs into buckets with similar fee rates within the
@@ -403,7 +404,7 @@ func (s *UtxoSweeper) SweepInput(input input.Input,
 // feeRateForPreference returns a fee rate for the given fee preference. It
 // ensures that the fee rate respects the bounds of the UtxoSweeper.
 func (s *UtxoSweeper) feeRateForPreference(
-	feePreference FeePreference) (lnwallet.SatPerKWeight, error) {
+	feePreference FeePreference) (chainfee.SatPerKWeight, error) {
 
 	// Ensure a type of fee preference is specified to prevent using a
 	// default below.
@@ -637,10 +638,10 @@ func (s *UtxoSweeper) collector(blockEpochs <-chan *chainntnfs.BlockEpoch) {
 // bucketForFeeReate determines the proper bucket for a fee rate. This is done
 // in order to batch inputs with similar fee rates together.
 func (s *UtxoSweeper) bucketForFeeRate(
-	feeRate lnwallet.SatPerKWeight) lnwallet.SatPerKWeight {
+	feeRate chainfee.SatPerKWeight) chainfee.SatPerKWeight {
 
-	minBucket := s.relayFeeRate + lnwallet.SatPerKWeight(s.cfg.FeeRateBucketSize)
-	return lnwallet.SatPerKWeight(
+	minBucket := s.relayFeeRate + chainfee.SatPerKWeight(s.cfg.FeeRateBucketSize)
+	return chainfee.SatPerKWeight(
 		math.Ceil(float64(feeRate) / float64(minBucket)),
 	)
 }
@@ -650,8 +651,8 @@ func (s *UtxoSweeper) bucketForFeeRate(
 // sweep fee rate, which is determined by calculating the average fee rate of
 // all inputs within that cluster.
 func (s *UtxoSweeper) clusterBySweepFeeRate() []inputCluster {
-	bucketInputs := make(map[lnwallet.SatPerKWeight]pendingInputs)
-	inputFeeRates := make(map[wire.OutPoint]lnwallet.SatPerKWeight)
+	bucketInputs := make(map[chainfee.SatPerKWeight]pendingInputs)
+	inputFeeRates := make(map[wire.OutPoint]chainfee.SatPerKWeight)
 
 	// First, we'll group together all inputs with similar fee rates. This
 	// is done by determining the fee rate bucket they should belong in.
@@ -678,11 +679,11 @@ func (s *UtxoSweeper) clusterBySweepFeeRate() []inputCluster {
 	// calculating the average fee rate of the inputs within each set.
 	inputClusters := make([]inputCluster, 0, len(bucketInputs))
 	for _, inputs := range bucketInputs {
-		var sweepFeeRate lnwallet.SatPerKWeight
+		var sweepFeeRate chainfee.SatPerKWeight
 		for op := range inputs {
 			sweepFeeRate += inputFeeRates[op]
 		}
-		sweepFeeRate /= lnwallet.SatPerKWeight(len(inputs))
+		sweepFeeRate /= chainfee.SatPerKWeight(len(inputs))
 		inputClusters = append(inputClusters, inputCluster{
 			sweepFeeRate: sweepFeeRate,
 			inputs:       inputs,
@@ -836,7 +837,7 @@ func (s *UtxoSweeper) getInputLists(cluster inputCluster,
 
 // sweep takes a set of preselected inputs, creates a sweep tx and publishes the
 // tx. The output address is only marked as used if the publish succeeds.
-func (s *UtxoSweeper) sweep(inputs inputSet, feeRate lnwallet.SatPerKWeight,
+func (s *UtxoSweeper) sweep(inputs inputSet, feeRate chainfee.SatPerKWeight,
 	currentHeight int32) error {
 
 	// Generate an output script if there isn't an unused script available.

sweep/sweeper_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 var (
@@ -99,7 +100,7 @@ func createSweeperTestContext(t *testing.T) *sweeperTestContext {
 
 	backend := newMockBackend(notifier)
 
-	estimator := newMockFeeEstimator(10000, lnwallet.FeePerKwFloor)
+	estimator := newMockFeeEstimator(10000, chainfee.FeePerKwFloor)
 
 	publishChan := make(chan wire.MsgTx, 2)
 	ctx := &sweeperTestContext{
@@ -314,7 +315,7 @@ func assertTxSweepsInputs(t *testing.T, sweepTx *wire.MsgTx,
 // NOTE: This assumes that transactions only have one output, as this is the
 // only type of transaction the UtxoSweeper can create at the moment.
 func assertTxFeeRate(t *testing.T, tx *wire.MsgTx,
-	expectedFeeRate lnwallet.SatPerKWeight, inputs ...input.Input) {
+	expectedFeeRate chainfee.SatPerKWeight, inputs ...input.Input) {
 
 	t.Helper()
 
@@ -994,11 +995,11 @@ func TestDifferentFeePreferences(t *testing.T) {
 	// this to ensure the sweeper can broadcast distinct transactions for
 	// each sweep with a different fee preference.
 	lowFeePref := FeePreference{ConfTarget: 12}
-	lowFeeRate := lnwallet.SatPerKWeight(5000)
+	lowFeeRate := chainfee.SatPerKWeight(5000)
 	ctx.estimator.blocksToFee[lowFeePref.ConfTarget] = lowFeeRate
 
 	highFeePref := FeePreference{ConfTarget: 6}
-	highFeeRate := lnwallet.SatPerKWeight(10000)
+	highFeeRate := chainfee.SatPerKWeight(10000)
 	ctx.estimator.blocksToFee[highFeePref.ConfTarget] = highFeeRate
 
 	input1 := spendableInputs[0]
@@ -1116,7 +1117,7 @@ func TestBumpFeeRBF(t *testing.T) {
 	ctx := createSweeperTestContext(t)
 
 	lowFeePref := FeePreference{ConfTarget: 144}
-	lowFeeRate := lnwallet.FeePerKwFloor
+	lowFeeRate := chainfee.FeePerKwFloor
 	ctx.estimator.blocksToFee[lowFeePref.ConfTarget] = lowFeeRate
 
 	// We'll first try to bump the fee of an output currently unknown to the

sweep/txgenerator.go

@@ -11,7 +11,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/wallet/txrules"
 	"github.com/lightningnetwork/lnd/input"
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 var (
@@ -31,7 +31,7 @@ type inputSet []input.Input
 // inputs are skipped. No input sets with a total value after fees below the
 // dust limit are returned.
 func generateInputPartitionings(sweepableInputs []input.Input,
-	relayFeePerKW, feePerKW lnwallet.SatPerKWeight,
+	relayFeePerKW, feePerKW chainfee.SatPerKWeight,
 	maxInputsPerTx int) ([]inputSet, error) {
 
 	// Calculate dust limit based on the P2WPKH output script of the sweep
@@ -116,7 +116,7 @@ func generateInputPartitionings(sweepableInputs []input.Input,
 // minimizing any negative externalities we cause for the Bitcoin system as a
 // whole.
 func getPositiveYieldInputs(sweepableInputs []input.Input, maxInputs int,
-	feePerKW lnwallet.SatPerKWeight) (int, btcutil.Amount) {
+	feePerKW chainfee.SatPerKWeight) (int, btcutil.Amount) {
 
 	var weightEstimate input.TxWeightEstimator
 
@@ -169,7 +169,7 @@ func getPositiveYieldInputs(sweepableInputs []input.Input, maxInputs int,
 
 // createSweepTx builds a signed tx spending the inputs to a the output script.
 func createSweepTx(inputs []input.Input, outputPkScript []byte,
-	currentBlockHeight uint32, feePerKw lnwallet.SatPerKWeight,
+	currentBlockHeight uint32, feePerKw chainfee.SatPerKWeight,
 	signer input.Signer) (*wire.MsgTx, error) {
 
 	inputs, txWeight := getWeightEstimate(inputs)

sweep/walletsweep.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 const (
@@ -27,7 +28,7 @@ type FeePreference struct {
 
 	// FeeRate if non-zero, signals a fee pre fence expressed in the fee
 	// rate expressed in sat/kw for a particular transaction.
-	FeeRate lnwallet.SatPerKWeight
+	FeeRate chainfee.SatPerKWeight
 }
 
 // String returns a human-readable string of the fee preference.
@@ -42,8 +43,8 @@ func (p FeePreference) String() string {
 // an estimator, a confirmation target, and a manual value for sat/byte. A
 // value is chosen based on the two free parameters as one, or both of them can
 // be zero.
-func DetermineFeePerKw(feeEstimator lnwallet.FeeEstimator,
-	feePref FeePreference) (lnwallet.SatPerKWeight, error) {
+func DetermineFeePerKw(feeEstimator chainfee.Estimator,
+	feePref FeePreference) (chainfee.SatPerKWeight, error) {
 
 	switch {
 	// If both values are set, then we'll return an error as we require a
@@ -70,12 +71,12 @@ func DetermineFeePerKw(feeEstimator lnwallet.FeeEstimator,
 	// internally.
 	case feePref.FeeRate != 0:
 		feePerKW := feePref.FeeRate
-		if feePerKW < lnwallet.FeePerKwFloor {
+		if feePerKW < chainfee.FeePerKwFloor {
 			log.Infof("Manual fee rate input of %d sat/kw is "+
 				"too low, using %d sat/kw instead", feePerKW,
-				lnwallet.FeePerKwFloor)
+				chainfee.FeePerKwFloor)
 
-			feePerKW = lnwallet.FeePerKwFloor
+			feePerKW = chainfee.FeePerKwFloor
 		}
 
 		return feePerKW, nil
@@ -152,10 +153,10 @@ type WalletSweepPackage struct {
 // by the delivery address. The sweep transaction will be crafted with the
 // target fee rate, and will use the utxoSource and outpointLocker as sources
 // for wallet funds.
-func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
+func CraftSweepAllTx(feeRate chainfee.SatPerKWeight, blockHeight uint32,
 	deliveryAddr btcutil.Address, coinSelectLocker CoinSelectionLocker,
 	utxoSource UtxoSource, outpointLocker OutpointLocker,
-	feeEstimator lnwallet.FeeEstimator,
+	feeEstimator chainfee.Estimator,
 	signer input.Signer) (*WalletSweepPackage, error) {
 
 	// TODO(roasbeef): turn off ATPL as well when available?

sweep/walletsweep_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 
 // TestDetermineFeePerKw tests that given a fee preference, the
@@ -17,8 +18,8 @@ import (
 func TestDetermineFeePerKw(t *testing.T) {
 	t.Parallel()
 
-	defaultFee := lnwallet.SatPerKWeight(999)
-	relayFee := lnwallet.SatPerKWeight(300)
+	defaultFee := chainfee.SatPerKWeight(999)
+	relayFee := chainfee.SatPerKWeight(300)
 
 	feeEstimator := newMockFeeEstimator(defaultFee, relayFee)
 
@@ -35,7 +36,7 @@ func TestDetermineFeePerKw(t *testing.T) {
 
 		// fee is the value the DetermineFeePerKw should return given
 		// the FeePreference above
-		fee lnwallet.SatPerKWeight
+		fee chainfee.SatPerKWeight
 
 		// fail determines if this test case should fail or not.
 		fail bool
@@ -43,9 +44,9 @@ func TestDetermineFeePerKw(t *testing.T) {
 		// A fee rate below the fee rate floor should output the floor.
 		{
 			feePref: FeePreference{
-				FeeRate: lnwallet.SatPerKWeight(99),
+				FeeRate: chainfee.SatPerKWeight(99),
 			},
-			fee: lnwallet.FeePerKwFloor,
+			fee: chainfee.FeePerKwFloor,
 		},
 
 		// A fee rate above the floor, should pass through and return