Merge pull request #89 from wpaulino/loop-out-conf-target

loopout: compare delta from htlc expiry correctly

Author: alexbosworth

loopout.go

@@ -597,7 +597,7 @@ func (s *loopOutSwap) sweep(ctx context.Context,
 	// close to the expiration height, in which case we'll use the default
 	// if it is better than what the client provided.
 	confTarget := s.SweepConfTarget
-	if s.CltvExpiry-s.height >= DefaultSweepConfTargetDelta &&
+	if s.CltvExpiry-s.height <= DefaultSweepConfTargetDelta &&
 		confTarget > DefaultSweepConfTarget {
 		confTarget = DefaultSweepConfTarget
 	}

loopout_test.go

@@ -6,6 +6,9 @@ import (
 	"testing"
 	"time"
 
+	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
 	"github.com/lightninglabs/loop/lndclient"
 	"github.com/lightninglabs/loop/loopdb"
 	"github.com/lightninglabs/loop/sweep"
@@ -99,3 +102,166 @@ func TestLateHtlcPublish(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+// TestCustomSweepConfTarget ensures we are able to sweep a Loop Out HTLC with a
+// custom confirmation target.
+func TestCustomSweepConfTarget(t *testing.T) {
+	defer test.Guard(t)()
+
+	lnd := test.NewMockLnd()
+	ctx := test.NewContext(t, lnd)
+
+	// Use the highest sweep confirmation target before we attempt to use
+	// the default.
+	testRequest.SweepConfTarget = testLoopOutOnChainCltvDelta -
+		DefaultSweepConfTargetDelta - 1
+
+	// Set up custom fee estimates such that the lower confirmation target
+	// yields a much higher fee rate.
+	ctx.Lnd.SetFeeEstimate(testRequest.SweepConfTarget, 250)
+	ctx.Lnd.SetFeeEstimate(DefaultSweepConfTarget, 10000)
+
+	cfg := &swapConfig{
+		lnd:    &lnd.LndServices,
+		store:  newStoreMock(t),
+		server: newServerMock(),
+	}
+	swap, err := newLoopOutSwap(
+		context.Background(), cfg, ctx.Lnd.Height, testRequest,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Set up the required dependencies to execute the swap.
+	//
+	// TODO: create test context similar to loopInTestContext.
+	sweeper := &sweep.Sweeper{Lnd: &lnd.LndServices}
+	blockEpochChan := make(chan interface{})
+	statusChan := make(chan SwapInfo)
+	expiryChan := make(chan time.Time)
+	timerFactory := func(expiry time.Duration) <-chan time.Time {
+		return expiryChan
+	}
+
+	errChan := make(chan error)
+	go func() {
+		err := swap.execute(context.Background(), &executeConfig{
+			statusChan:     statusChan,
+			blockEpochChan: blockEpochChan,
+			timerFactory:   timerFactory,
+			sweeper:        sweeper,
+		}, ctx.Lnd.Height)
+		if err != nil {
+			logger.Error(err)
+		}
+		errChan <- err
+	}()
+
+	// The swap should be found in its initial state.
+	cfg.store.(*storeMock).assertLoopOutStored()
+	state := <-statusChan
+	if state.State != loopdb.StateInitiated {
+		t.Fatal("unexpected state")
+	}
+
+	// We'll then pay both the swap and prepay invoice, which should trigger
+	// the server to publish the on-chain HTLC.
+	signalSwapPaymentResult := ctx.AssertPaid(swapInvoiceDesc)
+	signalPrepaymentResult := ctx.AssertPaid(prepayInvoiceDesc)
+
+	signalSwapPaymentResult(nil)
+	signalPrepaymentResult(nil)
+
+	// Notify the confirmation notification for the HTLC.
+	ctx.AssertRegisterConf()
+
+	blockEpochChan <- int32(ctx.Lnd.Height + 1)
+
+	htlcTx := wire.NewMsgTx(2)
+	htlcTx.AddTxOut(&wire.TxOut{
+		Value:    int64(swap.AmountRequested),
+		PkScript: swap.htlc.PkScript,
+	})
+
+	ctx.NotifyConf(htlcTx)
+
+	// The client should then register for a spend of the HTLC and attempt
+	// to sweep it using the custom confirmation target.
+	ctx.AssertRegisterSpendNtfn(swap.htlc.PkScript)
+
+	expiryChan <- time.Now()
+
+	cfg.store.(*storeMock).assertLoopOutState(loopdb.StatePreimageRevealed)
+	status := <-statusChan
+	if status.State != loopdb.StatePreimageRevealed {
+		t.Fatalf("expected state %v, got %v",
+			loopdb.StatePreimageRevealed, status.State)
+	}
+
+	// assertSweepTx performs some sanity checks on a sweep transaction to
+	// ensure it was constructed correctly.
+	assertSweepTx := func(expConfTarget int32) *wire.MsgTx {
+		t.Helper()
+
+		sweepTx := ctx.ReceiveTx()
+		if sweepTx.TxIn[0].PreviousOutPoint.Hash != htlcTx.TxHash() {
+			t.Fatalf("expected sweep tx to spend %v, got %v",
+				htlcTx.TxHash(), sweepTx.TxIn[0].PreviousOutPoint)
+		}
+
+		// The fee used for the sweep transaction is an estimate based
+		// on the maximum witness size, so we should expect to see a
+		// lower fee when using the actual witness size of the
+		// transaction.
+		fee := btcutil.Amount(
+			htlcTx.TxOut[0].Value - sweepTx.TxOut[0].Value,
+		)
+
+		weight := blockchain.GetTransactionWeight(btcutil.NewTx(sweepTx))
+		feeRate, err := ctx.Lnd.WalletKit.EstimateFee(
+			context.Background(), expConfTarget,
+		)
+		if err != nil {
+			t.Fatalf("unable to retrieve fee estimate: %v", err)
+		}
+		minFee := feeRate.FeeForWeight(weight)
+		maxFee := btcutil.Amount(float64(minFee) * 1.1)
+
+		if fee < minFee && fee > maxFee {
+			t.Fatalf("expected sweep tx to have fee between %v-%v, "+
+				"got %v", minFee, maxFee, fee)
+		}
+
+		return sweepTx
+	}
+
+	// The sweep should have a fee that corresponds to the custom
+	// confirmation target.
+	sweepTx := assertSweepTx(testRequest.SweepConfTarget)
+
+	// We'll then notify the height at which we begin using the default
+	// confirmation target.
+	defaultConfTargetHeight := ctx.Lnd.Height + testLoopOutOnChainCltvDelta -
+		DefaultSweepConfTargetDelta
+	blockEpochChan <- int32(defaultConfTargetHeight)
+	expiryChan <- time.Now()
+
+	// We should expect to see another sweep using the higher fee since the
+	// spend hasn't been confirmed yet.
+	sweepTx = assertSweepTx(DefaultSweepConfTarget)
+
+	// Notify the spend so that the swap reaches its final state.
+	ctx.NotifySpend(sweepTx, 0)
+
+	cfg.store.(*storeMock).assertLoopOutState(loopdb.StateSuccess)
+	status = <-statusChan
+	if status.State != loopdb.StateSuccess {
+		t.Fatalf("expected state %v, got %v", loopdb.StateSuccess,
+			status.State)
+	}
+
+	if err := <-errChan; err != nil {
+		t.Fatal(err)
+	}
+}

store_mock_test.go

@@ -170,8 +170,8 @@ func (s *storeMock) UpdateLoopIn(hash lntypes.Hash, time time.Time,
 	}
 
 	updates = append(updates, state)
-	s.loopOutUpdates[hash] = updates
-	s.loopOutUpdateChan <- state
+	s.loopInUpdates[hash] = updates
+	s.loopInUpdateChan <- state
 
 	return nil
 }
@@ -205,6 +205,15 @@ func (s *storeMock) assertLoopOutStored() {
 	}
 }
 
+func (s *storeMock) assertLoopOutState(expectedState loopdb.SwapState) {
+	s.t.Helper()
+
+	state := <-s.loopOutUpdateChan
+	if state.State != expectedState {
+		s.t.Fatalf("expected state %v, got %v", expectedState, state)
+	}
+}
+
 func (s *storeMock) assertLoopInStored() {
 	s.t.Helper()
 
@@ -214,9 +223,9 @@ func (s *storeMock) assertLoopInStored() {
 func (s *storeMock) assertLoopInState(expectedState loopdb.SwapState) {
 	s.t.Helper()
 
-	state := <-s.loopOutUpdateChan
+	state := <-s.loopInUpdateChan
 	if state.State != expectedState {
-		s.t.Fatalf("unexpected state")
+		s.t.Fatalf("expected state %v, got %v", expectedState, state)
 	}
 }
 

test/lnd_services_mock.go

@@ -6,12 +6,12 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
-	"github.com/lightningnetwork/lnd/lntypes"
-	"github.com/lightningnetwork/lnd/zpay32"
-
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightninglabs/loop/lndclient"
 	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/zpay32"
 )
 
 var testStartingHeight = int32(600)
@@ -20,7 +20,9 @@ var testStartingHeight = int32(600)
 // tests.
 func NewMockLnd() *LndMockServices {
 	lightningClient := &mockLightningClient{}
-	walletKit := &mockWalletKit{}
+	walletKit := &mockWalletKit{
+		feeEstimates: make(map[int32]lnwallet.SatPerKWeight),
+	}
 	chainNotifier := &mockChainNotifier{}
 	signer := &mockSigner{}
 	invoices := &mockInvoices{}
@@ -197,3 +199,9 @@ func (s *LndMockServices) DecodeInvoice(request string) (*zpay32.Invoice,
 
 	return zpay32.Decode(request, s.ChainParams)
 }
+
+func (s *LndMockServices) SetFeeEstimate(confTarget int32,
+	feeEstimate lnwallet.SatPerKWeight) {
+
+	s.WalletKit.(*mockWalletKit).feeEstimates[confTarget] = feeEstimate
+}

test/walletkit_mock.go

@@ -8,15 +8,19 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/lightninglabs/loop/lndclient"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
 type mockWalletKit struct {
-	lnd      *LndMockServices
-	keyIndex int32
+	lnd          *LndMockServices
+	keyIndex     int32
+	feeEstimates map[int32]lnwallet.SatPerKWeight
 }
 
+var _ lndclient.WalletKitClient = (*mockWalletKit)(nil)
+
 func (m *mockWalletKit) DeriveNextKey(ctx context.Context, family int32) (
 	*keychain.KeyDescriptor, error) {
 
@@ -87,9 +91,15 @@ func (m *mockWalletKit) SendOutputs(ctx context.Context, outputs []*wire.TxOut,
 
 func (m *mockWalletKit) EstimateFee(ctx context.Context, confTarget int32) (
 	lnwallet.SatPerKWeight, error) {
+
 	if confTarget <= 1 {
 		return 0, errors.New("conf target must be greater than 1")
 	}
 
-	return 10000, nil
+	feeEstimate, ok := m.feeEstimates[confTarget]
+	if !ok {
+		return 10000, nil
+	}
+
+	return feeEstimate, nil
 }