Merge pull request #548 from GeorgeTsagk/autoloop-amount-backoff

Autoloop amount backoff

liquidity/autoloop_test.go

@@ -199,16 +199,30 @@ func TestAutoLoopEnabled(t *testing.T) {
 				},
 			},
 		}
+
+		singleLoopOut = &loopdb.LoopOut{
+			Loop: loopdb.Loop{
+				Events: []*loopdb.LoopEvent{
+					{
+						SwapStateData: loopdb.SwapStateData{
+							State: loopdb.StateInitiated,
+						},
+					},
+				},
+			},
+		}
 	)
 
 	// Tick our autolooper with no existing swaps, we expect a loop out
 	// swap to be dispatched for each channel.
 	step := &autoloopStep{
-		minAmt:      1,
-		maxAmt:      amt + 1,
-		quotesOut:   quotes,
-		expectedOut: loopOuts,
+		minAmt:            1,
+		maxAmt:            amt + 1,
+		quotesOut:         quotes,
+		expectedOut:       loopOuts,
+		existingOutSingle: singleLoopOut,
 	}
+
 	c.autoloop(step)
 
 	// Tick again with both of our swaps in progress. We haven't shifted our
@@ -220,9 +234,10 @@ func TestAutoLoopEnabled(t *testing.T) {
 	}
 
 	step = &autoloopStep{
-		minAmt:      1,
-		maxAmt:      amt + 1,
-		existingOut: existing,
+		minAmt:            1,
+		maxAmt:            amt + 1,
+		existingOut:       existing,
+		existingOutSingle: singleLoopOut,
 	}
 	c.autoloop(step)
 
@@ -278,11 +293,12 @@ func TestAutoLoopEnabled(t *testing.T) {
 	// still has balances which reflect that we need to swap), but nothing
 	// for channel 2, since it has had a failure.
 	step = &autoloopStep{
-		minAmt:      1,
-		maxAmt:      amt + 1,
-		existingOut: existing,
-		quotesOut:   quotes,
-		expectedOut: loopOuts,
+		minAmt:            1,
+		maxAmt:            amt + 1,
+		existingOut:       existing,
+		quotesOut:         quotes,
+		expectedOut:       loopOuts,
+		existingOutSingle: singleLoopOut,
 	}
 	c.autoloop(step)
 
@@ -299,10 +315,11 @@ func TestAutoLoopEnabled(t *testing.T) {
 	}
 
 	step = &autoloopStep{
-		minAmt:      1,
-		maxAmt:      amt + 1,
-		existingOut: existing,
-		quotesOut:   quotes,
+		minAmt:            1,
+		maxAmt:            amt + 1,
+		existingOut:       existing,
+		quotesOut:         quotes,
+		existingOutSingle: singleLoopOut,
 	}
 	c.autoloop(step)
 
@@ -446,13 +463,27 @@ func TestAutoloopAddress(t *testing.T) {
 				},
 			},
 		}
+
+		singleLoopOut = &loopdb.LoopOut{
+			Loop: loopdb.Loop{
+				Events: []*loopdb.LoopEvent{
+					{
+						SwapStateData: loopdb.SwapStateData{
+							State: loopdb.StateHtlcPublished,
+						},
+					},
+				},
+			},
+		}
 	)
 
 	step := &autoloopStep{
-		minAmt:      1,
-		maxAmt:      amt + 1,
-		quotesOut:   quotes,
-		expectedOut: loopOuts,
+		minAmt:            1,
+		maxAmt:            amt + 1,
+		quotesOut:         quotes,
+		expectedOut:       loopOuts,
+		existingOutSingle: singleLoopOut,
+		keepDestAddr:      true,
 	}
 	c.autoloop(step)
 
@@ -606,6 +637,18 @@ func TestCompositeRules(t *testing.T) {
 				},
 			},
 		}
+
+		singleLoopOut = &loopdb.LoopOut{
+			Loop: loopdb.Loop{
+				Events: []*loopdb.LoopEvent{
+					{
+						SwapStateData: loopdb.SwapStateData{
+							State: loopdb.StateHtlcPublished,
+						},
+					},
+				},
+			},
+		}
 	)
 
 	// Tick our autolooper with no existing swaps, we expect a loop out
@@ -613,10 +656,11 @@ func TestCompositeRules(t *testing.T) {
 	// maximum to be greater than the swap amount for our peer swap (which
 	// is the larger of the two swaps).
 	step := &autoloopStep{
-		minAmt:      1,
-		maxAmt:      peerAmount + 1,
-		quotesOut:   quotes,
-		expectedOut: loopOuts,
+		minAmt:            1,
+		maxAmt:            peerAmount + 1,
+		quotesOut:         quotes,
+		expectedOut:       loopOuts,
+		existingOutSingle: singleLoopOut,
 	}
 	c.autoloop(step)
 
@@ -928,6 +972,18 @@ func TestAutoloopBothTypes(t *testing.T) {
 			Label:          labels.AutoloopLabel(swap.TypeIn),
 			Initiator:      autoloopSwapInitiator,
 		}
+
+		singleLoopOut = &loopdb.LoopOut{
+			Loop: loopdb.Loop{
+				Events: []*loopdb.LoopEvent{
+					{
+						SwapStateData: loopdb.SwapStateData{
+							State: loopdb.StateHtlcPublished,
+						},
+					},
+				},
+			},
+		}
 	)
 
 	step := &autoloopStep{
@@ -961,6 +1017,7 @@ func TestAutoloopBothTypes(t *testing.T) {
 				},
 			},
 		},
+		existingOutSingle: singleLoopOut,
 	}
 	c.autoloop(step)
 	c.stop()

liquidity/autoloop_testcontext_test.go

@@ -2,7 +2,9 @@ package liquidity
 
 import (
 	"context"
+	"reflect"
 	"testing"
+	"time"
 
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightninglabs/lndclient"
@@ -11,8 +13,10 @@ import (
 	"github.com/lightninglabs/loop/swap"
 	"github.com/lightninglabs/loop/test"
 	"github.com/lightningnetwork/lnd/clock"
+	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/ticker"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 type autoloopTestCtx struct {
@@ -45,9 +49,17 @@ type autoloopTestCtx struct {
 	// loopOuts is a channel that we get existing loop out swaps on.
 	loopOuts chan []*loopdb.LoopOut
 
+	// loopOutSingle is the single loop out returned from fetching a single
+	// swap from store.
+	loopOutSingle *loopdb.LoopOut
+
 	// loopIns is a channel that we get existing loop in swaps on.
 	loopIns chan []*loopdb.LoopIn
 
+	// loopInSingle is the single loop in returned from fetching a single
+	// swap from store.
+	loopInSingle *loopdb.LoopIn
+
 	// restrictions is a channel that we get swap restrictions on.
 	restrictions chan *Restrictions
 
@@ -131,6 +143,9 @@ func newAutoloopTestCtx(t *testing.T, parameters Parameters,
 		ListLoopOut: func() ([]*loopdb.LoopOut, error) {
 			return <-testCtx.loopOuts, nil
 		},
+		GetLoopOut: func(hash lntypes.Hash) (*loopdb.LoopOut, error) {
+			return testCtx.loopOutSingle, nil
+		},
 		ListLoopIn: func() ([]*loopdb.LoopIn, error) {
 			return <-testCtx.loopIns, nil
 		},
@@ -188,6 +203,10 @@ func newAutoloopTestCtx(t *testing.T, parameters Parameters,
 	testCtx.manager = NewManager(cfg)
 	err := testCtx.manager.setParameters(context.Background(), parameters)
 	assert.NoError(t, err)
+	// Override the payments check interval for the tests in order to not
+	// timeout.
+	testCtx.manager.params.CustomPaymentCheckInterval =
+		150 * time.Millisecond
 	<-done
 	return testCtx
 }
@@ -241,14 +260,17 @@ type loopInRequestResp struct {
 // autoloopStep contains all of the information to required to step
 // through an autoloop tick.
 type autoloopStep struct {
-	minAmt      btcutil.Amount
-	maxAmt      btcutil.Amount
-	existingOut []*loopdb.LoopOut
-	existingIn  []*loopdb.LoopIn
-	quotesOut   []quoteRequestResp
-	quotesIn    []quoteInRequestResp
-	expectedOut []loopOutRequestResp
-	expectedIn  []loopInRequestResp
+	minAmt            btcutil.Amount
+	maxAmt            btcutil.Amount
+	existingOut       []*loopdb.LoopOut
+	existingOutSingle *loopdb.LoopOut
+	existingIn        []*loopdb.LoopIn
+	existingInSingle  *loopdb.LoopIn
+	quotesOut         []quoteRequestResp
+	quotesIn          []quoteInRequestResp
+	expectedOut       []loopOutRequestResp
+	expectedIn        []loopInRequestResp
+	keepDestAddr      bool
 }
 
 // autoloop walks our test context through the process of triggering our
@@ -269,6 +291,9 @@ func (c *autoloopTestCtx) autoloop(step *autoloopStep) {
 	c.loopOuts <- step.existingOut
 	c.loopIns <- step.existingIn
 
+	c.loopOutSingle = step.existingOutSingle
+	c.loopInSingle = step.existingInSingle
+
 	// Assert that we query the server for a quote for each of our
 	// recommended swaps. Note that this differs from our set of expected
 	// swaps because we may get quotes for suggested swaps but then just
@@ -299,25 +324,77 @@ func (c *autoloopTestCtx) autoloop(step *autoloopStep) {
 		c.quotes <- expected.quote
 	}
 
-	// Assert that we dispatch the expected set of swaps.
-	for _, expected := range step.expectedOut {
+	require.True(c.t, c.matchLoopOuts(step.expectedOut, step.keepDestAddr))
+	require.True(c.t, c.matchLoopIns(step.expectedIn))
+}
+
+// matchLoopOuts checks that the actual loop out requests we got match the
+// expected ones. The argument keepDestAddr is used to indicate whether we keep
+// the actual loops destination address for the comparison. This is useful
+// because we don't want to compare the destination address generated by the
+// wallet mock. We want to compare the destination address when testing the
+// autoloop DestAddr parameter for loop outs.
+func (c *autoloopTestCtx) matchLoopOuts(swaps []loopOutRequestResp,
+	keepDestAddr bool) bool {
+
+	swapsCopy := make([]loopOutRequestResp, len(swaps))
+	copy(swapsCopy, swaps)
+
+	length := len(swapsCopy)
+
+	for i := 0; i < length; i++ {
 		actual := <-c.outRequest
 
-		// Set our destination address to nil so that we do not need to
-		// provide the address that is obtained by the mock wallet kit.
-		if expected.request.DestAddr == nil {
+		if !keepDestAddr {
 			actual.DestAddr = nil
 		}
 
-		assert.Equal(c.t, expected.request, actual)
-		c.loopOut <- expected.response
+	inner:
+		for index, swap := range swapsCopy {
+			equal := reflect.DeepEqual(swap.request, actual)
+
+			if equal {
+				c.loopOut <- swap.response
+
+				swapsCopy = append(
+					swapsCopy[:index],
+					swapsCopy[index+1:]...,
+				)
+
+				break inner
+			}
+		}
 	}
 
-	for _, expected := range step.expectedIn {
+	return len(swapsCopy) == 0
+}
+
+// matchLoopIns checks that the actual loop in requests we got match the
+// expected ones.
+func (c *autoloopTestCtx) matchLoopIns(
+	swaps []loopInRequestResp) bool {
+
+	swapsCopy := make([]loopInRequestResp, len(swaps))
+	copy(swapsCopy, swaps)
+
+	for i := 0; i < len(swapsCopy); i++ {
 		actual := <-c.inRequest
 
-		assert.Equal(c.t, expected.request, actual)
+	inner:
+		for i, swap := range swapsCopy {
+			equal := reflect.DeepEqual(swap.request, actual)
 
-		c.loopIn <- expected.response
+			if equal {
+				c.loopIn <- swap.response
+
+				swapsCopy = append(
+					swapsCopy[:i], swapsCopy[i+1:]...,
+				)
+
+				break inner
+			}
+		}
 	}
+
+	return len(swapsCopy) == 0
 }

liquidity/liquidity.go

@@ -48,6 +48,7 @@ import (
 	"github.com/lightninglabs/loop/swap"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/funding"
+	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
@@ -62,6 +63,22 @@ const (
 	// a channel is part of a temporarily failed swap.
 	defaultFailureBackoff = time.Hour * 24
 
+	// defaultAmountBackoff is the default backoff we apply to the amount
+	// of a loop out swap that failed the off-chain payments.
+	defaultAmountBackoff = float64(0.25)
+
+	// defaultAmountBackoffRetry is the default number of times we will
+	// perform an amount backoff to a loop out swap before we give up.
+	defaultAmountBackoffRetry = 5
+
+	// defaultSwapWaitTimeout is the default maximum amount of time we
+	// wait for a swap to reach a terminal state.
+	defaultSwapWaitTimeout = time.Hour * 24
+
+	// defaultPaymentCheckInterval is the default time that passes between
+	// checks for loop out payments status.
+	defaultPaymentCheckInterval = time.Second * 2
+
 	// defaultConfTarget is the default sweep target we use for loop outs.
 	// We get our inbound liquidity quickly using preimage push, so we can
 	// use a long conf target without worrying about ux impact.
@@ -78,7 +95,7 @@ const (
 
 	// DefaultAutoloopTicker is the default amount of time between automated
 	// swap checks.
-	DefaultAutoloopTicker = time.Minute * 10
+	DefaultAutoloopTicker = time.Minute * 20
 
 	// autoloopSwapInitiator is the value we send in the initiator field of
 	// a swap request when issuing an automatic swap.
@@ -164,6 +181,10 @@ type Config struct {
 	// ListLoopOut returns all of the loop our swaps stored on disk.
 	ListLoopOut func() ([]*loopdb.LoopOut, error)
 
+	// GetLoopOut returns a single loop out swap based on the provided swap
+	// hash.
+	GetLoopOut func(hash lntypes.Hash) (*loopdb.LoopOut, error)
+
 	// ListLoopIn returns all of the loop in swaps stored on disk.
 	ListLoopIn func() ([]*loopdb.LoopIn, error)
 
@@ -399,13 +420,10 @@ func (m *Manager) autoloop(ctx context.Context) error {
 			swap.DestAddr = m.params.DestAddr
 		}
 
-		loopOut, err := m.cfg.LoopOut(ctx, &swap)
-		if err != nil {
-			return err
-		}
-
-		log.Infof("loop out automatically dispatched: hash: %v, "+
-			"address: %v", loopOut.SwapHash, loopOut.HtlcAddress)
+		go m.dispatchStickyLoopOut(
+			ctx, swap, defaultAmountBackoffRetry,
+			defaultAmountBackoff,
+		)
 	}
 
 	for _, in := range suggestion.InSwaps {
@@ -1044,6 +1062,143 @@ func (m *Manager) refreshAutoloopBudget(ctx context.Context) {
 	}
 }
 
+// dispatchStickyLoopOut attempts to dispatch a loop out swap that will
+// automatically retry its execution with an amount based backoff.
+func (m *Manager) dispatchStickyLoopOut(ctx context.Context,
+	out loop.OutRequest, retryCount uint16, amountBackoff float64) {
+
+	for i := 0; i < int(retryCount); i++ {
+		// Dispatch the swap.
+		swap, err := m.cfg.LoopOut(ctx, &out)
+		if err != nil {
+			log.Errorf("unable to dispatch loop out, hash: %v, "+
+				"err: %v", swap.SwapHash, err)
+		}
+
+		log.Infof("loop out automatically dispatched: hash: %v, "+
+			"address: %v, amount %v", swap.SwapHash,
+			swap.HtlcAddress, out.Amount)
+
+		updates := make(chan *loopdb.SwapState, 1)
+
+		// Monitor the swap state and write the desired update to the
+		// update channel. We do not want to read all of the swap state
+		// updates, just the one that will help us assume the state of
+		// the off-chain payment.
+		go m.waitForSwapPayment(
+			ctx, swap.SwapHash, updates, defaultSwapWaitTimeout,
+		)
+
+		select {
+		case <-ctx.Done():
+			return
+
+		case update := <-updates:
+			if update == nil {
+				// If update is nil then no update occurred
+				// within the defined timeout period. It's
+				// better to return and not attempt a retry.
+				log.Debug(
+					"No payment update received for swap "+
+						"%v, skipping amount backoff",
+					swap.SwapHash,
+				)
+
+				return
+			}
+
+			if *update == loopdb.StateFailOffchainPayments {
+				// Save the old amount so we can log it.
+				oldAmt := out.Amount
+
+				// If we failed to pay the server, we will
+				// decrease the amount of the swap and try
+				// again.
+				out.Amount -= btcutil.Amount(
+					float64(out.Amount) * amountBackoff,
+				)
+
+				log.Infof("swap %v: amount backoff old amount="+
+					"%v, new amount=%v", swap.SwapHash,
+					oldAmt, out.Amount)
+
+				continue
+			} else {
+				// If the update channel did not return an
+				// off-chain payment failure we won't retry.
+				return
+			}
+		}
+	}
+}
+
+// waitForSwapPayment waits for a swap to progress beyond the stage of
+// forwarding the payment to the server through the network. It returns the
+// final update on the outcome through a channel.
+func (m *Manager) waitForSwapPayment(ctx context.Context, swapHash lntypes.Hash,
+	updateChan chan *loopdb.SwapState, timeout time.Duration) {
+
+	startTime := time.Now()
+	var (
+		swap     *loopdb.LoopOut
+		err      error
+		interval time.Duration
+	)
+
+	if m.params.CustomPaymentCheckInterval != 0 {
+		interval = m.params.CustomPaymentCheckInterval
+	} else {
+		interval = defaultPaymentCheckInterval
+	}
+
+	for time.Since(startTime) < timeout {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(interval):
+		}
+
+		swap, err = m.cfg.GetLoopOut(swapHash)
+		if err != nil {
+			log.Errorf(
+				"Error getting swap with hash %x: %v", swapHash,
+				err,
+			)
+			continue
+		}
+
+		// If no update has occurred yet, continue in order to wait.
+		update := swap.LastUpdate()
+		if update == nil {
+			continue
+		}
+
+		// Write the update if the swap has reached a state the helps
+		// us determine whether the off-chain payment successfully
+		// reached the destination.
+		switch update.State {
+		case loopdb.StateFailInsufficientValue:
+			fallthrough
+		case loopdb.StateSuccess:
+			fallthrough
+		case loopdb.StateFailSweepTimeout:
+			fallthrough
+		case loopdb.StateFailTimeout:
+			fallthrough
+		case loopdb.StatePreimageRevealed:
+			fallthrough
+		case loopdb.StateFailOffchainPayments:
+			updateChan <- &update.State
+			return
+		}
+	}
+
+	// If no update occurred within the defined timeout we return an empty
+	// update to the channel, causing the sticky loop out to not retry
+	// anymore.
+	updateChan <- nil
+}
+
 // swapTraffic contains a summary of our current and previously failed swaps.
 type swapTraffic struct {
 	ongoingLoopOut map[lnwire.ShortChannelID]bool

liquidity/parameters.go

@@ -87,6 +87,10 @@ type Parameters struct {
 	// ChannelRules are exclusively set to prevent overlap between peer
 	// and channel rules map to avoid ambiguity.
 	PeerRules map[route.Vertex]*SwapRule
+
+	// CustomPaymentCheckInterval is an optional custom interval to use when
+	// checking an autoloop loop out payments' payment status.
+	CustomPaymentCheckInterval time.Duration
 }
 
 // String returns the string representation of our parameters.

loopd/utils.go

@@ -72,6 +72,7 @@ func getLiquidityManager(client *loop.Client) *liquidity.Manager {
 		LoopOutQuote:         client.LoopOutQuote,
 		LoopInQuote:          client.LoopInQuote,
 		ListLoopOut:          client.Store.FetchLoopOutSwaps,
+		GetLoopOut:           client.Store.FetchLoopOutSwap,
 		ListLoopIn:           client.Store.FetchLoopInSwaps,
 		MinimumConfirmations: minConfTarget,
 		PutLiquidityParams:   client.Store.PutLiquidityParams,

loopdb/interface.go

@@ -12,6 +12,9 @@ type SwapStore interface {
 	// FetchLoopOutSwaps returns all swaps currently in the store.
 	FetchLoopOutSwaps() ([]*LoopOut, error)
 
+	// FetchLoopOutSwap returns the loop out swap with the given hash.
+	FetchLoopOutSwap(hash lntypes.Hash) (*LoopOut, error)
+
 	// CreateLoopOut adds an initiated swap to the store.
 	CreateLoopOut(hash lntypes.Hash, swap *LoopOutContract) error
 

loopdb/store.go

@@ -255,111 +255,12 @@ func (s *boltSwapStore) FetchLoopOutSwaps() ([]*LoopOut, error) {
 				return nil
 			}
 
-			// From the root bucket, we'll grab the next swap
-			// bucket for this swap from its swaphash.
-			swapBucket := rootBucket.Bucket(swapHash)
-			if swapBucket == nil {
-				return fmt.Errorf("swap bucket %x not found",
-					swapHash)
-			}
-
-			// With the main swap bucket obtained, we'll grab the
-			// raw swap contract bytes and decode it.
-			contractBytes := swapBucket.Get(contractKey)
-			if contractBytes == nil {
-				return errors.New("contract not found")
-			}
-
-			contract, err := deserializeLoopOutContract(
-				contractBytes, s.chainParams,
-			)
+			loop, err := s.fetchLoopOutSwap(rootBucket, swapHash)
 			if err != nil {
 				return err
 			}
 
-			// Get our label for this swap, if it is present.
-			contract.Label = getLabel(swapBucket)
-
-			// Read the list of concatenated outgoing channel ids
-			// that form the outgoing set.
-			setBytes := swapBucket.Get(outgoingChanSetKey)
-			if outgoingChanSetKey != nil {
-				r := bytes.NewReader(setBytes)
-			readLoop:
-				for {
-					var chanID uint64
-					err := binary.Read(r, byteOrder, &chanID)
-					switch {
-					case err == io.EOF:
-						break readLoop
-					case err != nil:
-						return err
-					}
-
-					contract.OutgoingChanSet = append(
-						contract.OutgoingChanSet,
-						chanID,
-					)
-				}
-			}
-
-			// Set our default number of confirmations for the swap.
-			contract.HtlcConfirmations = DefaultLoopOutHtlcConfirmations
-
-			// If we have the number of confirmations stored for
-			// this swap, we overwrite our default with the stored
-			// value.
-			confBytes := swapBucket.Get(confirmationsKey)
-			if confBytes != nil {
-				r := bytes.NewReader(confBytes)
-				err := binary.Read(
-					r, byteOrder, &contract.HtlcConfirmations,
-				)
-				if err != nil {
-					return err
-				}
-			}
-
-			updates, err := deserializeUpdates(swapBucket)
-			if err != nil {
-				return err
-			}
-
-			// Try to unmarshal the protocol version for the swap.
-			// If the protocol version is not stored (which is
-			// the case for old clients), we'll assume the
-			// ProtocolVersionUnrecorded instead.
-			contract.ProtocolVersion, err =
-				UnmarshalProtocolVersion(
-					swapBucket.Get(protocolVersionKey),
-				)
-			if err != nil {
-				return err
-			}
-
-			// Try to unmarshal the key locator.
-			if contract.ProtocolVersion >= ProtocolVersionHtlcV3 {
-				contract.ClientKeyLocator, err = UnmarshalKeyLocator(
-					swapBucket.Get(keyLocatorKey),
-				)
-				if err != nil {
-					return err
-				}
-			}
-
-			loop := LoopOut{
-				Loop: Loop{
-					Events: updates,
-				},
-				Contract: contract,
-			}
-
-			loop.Hash, err = lntypes.MakeHash(swapHash)
-			if err != nil {
-				return err
-			}
-
-			swaps = append(swaps, &loop)
+			swaps = append(swaps, loop)
 
 			return nil
 		})
@@ -371,53 +272,33 @@ func (s *boltSwapStore) FetchLoopOutSwaps() ([]*LoopOut, error) {
 	return swaps, nil
 }
 
-// deserializeUpdates deserializes the list of swap updates that are stored as a
-// key of the given bucket.
-func deserializeUpdates(swapBucket *bbolt.Bucket) ([]*LoopEvent, error) {
-	// Once we have the raw swap, we'll also need to decode
-	// each of the past updates to the swap itself.
-	stateBucket := swapBucket.Bucket(updatesBucketKey)
-	if stateBucket == nil {
-		return nil, errors.New("updates bucket not found")
-	}
-
-	// Deserialize and collect each swap update into our slice of swap
-	// events.
-	var updates []*LoopEvent
-	err := stateBucket.ForEach(func(k, v []byte) error {
-		updateBucket := stateBucket.Bucket(k)
-		if updateBucket == nil {
-			return fmt.Errorf("expected state sub-bucket for %x", k)
-		}
+// FetchLoopOutSwap returns the loop out swap with the given hash.
+//
+// NOTE: Part of the loopdb.SwapStore interface.
+func (s *boltSwapStore) FetchLoopOutSwap(hash lntypes.Hash) (*LoopOut, error) {
+	var swap *LoopOut
 
-		basicState := updateBucket.Get(basicStateKey)
-		if basicState == nil {
-			return errors.New("no basic state for update")
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		// First, we'll grab our main loop out bucket key.
+		rootBucket := tx.Bucket(loopOutBucketKey)
+		if rootBucket == nil {
+			return errors.New("bucket does not exist")
 		}
 
-		event, err := deserializeLoopEvent(basicState)
+		loop, err := s.fetchLoopOutSwap(rootBucket, hash[:])
 		if err != nil {
 			return err
 		}
 
-		// Deserialize htlc tx hash if this updates contains one.
-		htlcTxHashBytes := updateBucket.Get(htlcTxHashKey)
-		if htlcTxHashBytes != nil {
-			htlcTxHash, err := chainhash.NewHash(htlcTxHashBytes)
-			if err != nil {
-				return err
-			}
-			event.HtlcTxHash = htlcTxHash
-		}
+		swap = loop
 
-		updates = append(updates, event)
 		return nil
 	})
 	if err != nil {
 		return nil, err
 	}
 
-	return updates, nil
+	return swap, nil
 }
 
 // FetchLoopInSwaps returns all loop in swaps currently in the store.
@@ -442,71 +323,12 @@ func (s *boltSwapStore) FetchLoopInSwaps() ([]*LoopIn, error) {
 				return nil
 			}
 
-			// From the root bucket, we'll grab the next swap
-			// bucket for this swap from its swaphash.
-			swapBucket := rootBucket.Bucket(swapHash)
-			if swapBucket == nil {
-				return fmt.Errorf("swap bucket %x not found",
-					swapHash)
-			}
-
-			// With the main swap bucket obtained, we'll grab the
-			// raw swap contract bytes and decode it.
-			contractBytes := swapBucket.Get(contractKey)
-			if contractBytes == nil {
-				return errors.New("contract not found")
-			}
-
-			contract, err := deserializeLoopInContract(
-				contractBytes,
-			)
+			loop, err := s.fetchLoopInSwap(rootBucket, swapHash)
 			if err != nil {
 				return err
 			}
 
-			// Get our label for this swap, if it is present.
-			contract.Label = getLabel(swapBucket)
-
-			updates, err := deserializeUpdates(swapBucket)
-			if err != nil {
-				return err
-			}
-
-			// Try to unmarshal the protocol version for the swap.
-			// If the protocol version is not stored (which is
-			// the case for old clients), we'll assume the
-			// ProtocolVersionUnrecorded instead.
-			contract.ProtocolVersion, err =
-				UnmarshalProtocolVersion(
-					swapBucket.Get(protocolVersionKey),
-				)
-			if err != nil {
-				return err
-			}
-
-			// Try to unmarshal the key locator.
-			if contract.ProtocolVersion >= ProtocolVersionHtlcV3 {
-				contract.ClientKeyLocator, err = UnmarshalKeyLocator(
-					swapBucket.Get(keyLocatorKey),
-				)
-				if err != nil {
-					return err
-				}
-			}
-
-			loop := LoopIn{
-				Loop: Loop{
-					Events: updates,
-				},
-				Contract: contract,
-			}
-
-			loop.Hash, err = lntypes.MakeHash(swapHash)
-			if err != nil {
-				return err
-			}
-
-			swaps = append(swaps, &loop)
+			swaps = append(swaps, loop)
 
 			return nil
 		})
@@ -824,3 +646,243 @@ func (s *boltSwapStore) FetchLiquidityParams() ([]byte, error) {
 
 	return params, err
 }
+
+// fetchUpdates deserializes the list of swap updates that are stored as a
+// key of the given bucket.
+func fetchUpdates(swapBucket *bbolt.Bucket) ([]*LoopEvent, error) {
+	// Once we have the raw swap, we'll also need to decode
+	// each of the past updates to the swap itself.
+	stateBucket := swapBucket.Bucket(updatesBucketKey)
+	if stateBucket == nil {
+		return nil, errors.New("updates bucket not found")
+	}
+
+	// Deserialize and collect each swap update into our slice of swap
+	// events.
+	var updates []*LoopEvent
+	err := stateBucket.ForEach(func(k, v []byte) error {
+		updateBucket := stateBucket.Bucket(k)
+		if updateBucket == nil {
+			return fmt.Errorf("expected state sub-bucket for %x", k)
+		}
+
+		basicState := updateBucket.Get(basicStateKey)
+		if basicState == nil {
+			return errors.New("no basic state for update")
+		}
+
+		event, err := deserializeLoopEvent(basicState)
+		if err != nil {
+			return err
+		}
+
+		// Deserialize htlc tx hash if this updates contains one.
+		htlcTxHashBytes := updateBucket.Get(htlcTxHashKey)
+		if htlcTxHashBytes != nil {
+			htlcTxHash, err := chainhash.NewHash(htlcTxHashBytes)
+			if err != nil {
+				return err
+			}
+			event.HtlcTxHash = htlcTxHash
+		}
+
+		updates = append(updates, event)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return updates, nil
+}
+
+// fetchLoopOutSwap fetches and deserializes the raw swap bytes into a LoopOut
+// struct.
+func (s *boltSwapStore) fetchLoopOutSwap(rootBucket *bbolt.Bucket,
+	swapHash []byte) (*LoopOut, error) {
+
+	// From the root bucket, we'll grab the next swap
+	// bucket for this swap from its swaphash.
+	swapBucket := rootBucket.Bucket(swapHash)
+	if swapBucket == nil {
+		return nil, fmt.Errorf("swap bucket %x not found",
+			swapHash)
+	}
+
+	hash, err := lntypes.MakeHash(swapHash)
+	if err != nil {
+		return nil, err
+	}
+
+	// With the main swap bucket obtained, we'll grab the
+	// raw swap contract bytes and decode it.
+	contractBytes := swapBucket.Get(contractKey)
+	if contractBytes == nil {
+		return nil, errors.New("contract not found")
+	}
+
+	contract, err := deserializeLoopOutContract(
+		contractBytes, s.chainParams,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get our label for this swap, if it is present.
+	contract.Label = getLabel(swapBucket)
+
+	// Read the list of concatenated outgoing channel ids
+	// that form the outgoing set.
+	setBytes := swapBucket.Get(outgoingChanSetKey)
+	if outgoingChanSetKey != nil {
+		r := bytes.NewReader(setBytes)
+	readLoop:
+		for {
+			var chanID uint64
+			err := binary.Read(r, byteOrder, &chanID)
+			switch {
+			case err == io.EOF:
+				break readLoop
+			case err != nil:
+				return nil, err
+			}
+
+			contract.OutgoingChanSet = append(
+				contract.OutgoingChanSet,
+				chanID,
+			)
+		}
+	}
+
+	// Set our default number of confirmations for the swap.
+	contract.HtlcConfirmations = DefaultLoopOutHtlcConfirmations
+
+	// If we have the number of confirmations stored for
+	// this swap, we overwrite our default with the stored
+	// value.
+	confBytes := swapBucket.Get(confirmationsKey)
+	if confBytes != nil {
+		r := bytes.NewReader(confBytes)
+		err := binary.Read(
+			r, byteOrder, &contract.HtlcConfirmations,
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	updates, err := fetchUpdates(swapBucket)
+	if err != nil {
+		return nil, err
+	}
+
+	// Try to unmarshal the protocol version for the swap.
+	// If the protocol version is not stored (which is
+	// the case for old clients), we'll assume the
+	// ProtocolVersionUnrecorded instead.
+	contract.ProtocolVersion, err =
+		UnmarshalProtocolVersion(
+			swapBucket.Get(protocolVersionKey),
+		)
+	if err != nil {
+		return nil, err
+	}
+
+	// Try to unmarshal the key locator.
+	if contract.ProtocolVersion >= ProtocolVersionHtlcV3 {
+		contract.ClientKeyLocator, err = UnmarshalKeyLocator(
+			swapBucket.Get(keyLocatorKey),
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	loop := LoopOut{
+		Loop: Loop{
+			Events: updates,
+		},
+		Contract: contract,
+	}
+
+	loop.Hash, err = lntypes.MakeHash(hash[:])
+	if err != nil {
+		return nil, err
+	}
+
+	return &loop, nil
+}
+
+// fetchLoopInSwap fetches and deserializes the raw swap bytes into a LoopIn
+// struct.
+func (s *boltSwapStore) fetchLoopInSwap(rootBucket *bbolt.Bucket,
+	swapHash []byte) (*LoopIn, error) {
+
+	// From the root bucket, we'll grab the next swap
+	// bucket for this swap from its swaphash.
+	swapBucket := rootBucket.Bucket(swapHash)
+	if swapBucket == nil {
+		return nil, fmt.Errorf("swap bucket %x not found",
+			swapHash)
+	}
+
+	hash, err := lntypes.MakeHash(swapHash)
+	if err != nil {
+		return nil, err
+	}
+
+	// With the main swap bucket obtained, we'll grab the
+	// raw swap contract bytes and decode it.
+	contractBytes := swapBucket.Get(contractKey)
+	if contractBytes == nil {
+		return nil, errors.New("contract not found")
+	}
+
+	contract, err := deserializeLoopInContract(
+		contractBytes,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get our label for this swap, if it is present.
+	contract.Label = getLabel(swapBucket)
+
+	updates, err := fetchUpdates(swapBucket)
+	if err != nil {
+		return nil, err
+	}
+
+	// Try to unmarshal the protocol version for the swap.
+	// If the protocol version is not stored (which is
+	// the case for old clients), we'll assume the
+	// ProtocolVersionUnrecorded instead.
+	contract.ProtocolVersion, err =
+		UnmarshalProtocolVersion(
+			swapBucket.Get(protocolVersionKey),
+		)
+	if err != nil {
+		return nil, err
+	}
+
+	// Try to unmarshal the key locator.
+	if contract.ProtocolVersion >= ProtocolVersionHtlcV3 {
+		contract.ClientKeyLocator, err = UnmarshalKeyLocator(
+			swapBucket.Get(keyLocatorKey),
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	loop := LoopIn{
+		Loop: Loop{
+			Events: updates,
+		},
+		Contract: contract,
+	}
+
+	loop.Hash = hash
+
+	return &loop, nil
+}

loopdb/store_test.go

@@ -5,7 +5,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"reflect"
 	"testing"
 	"time"
 
@@ -96,24 +95,20 @@ func TestLoopOutStore(t *testing.T) {
 // swap store for specific swap parameters.
 func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 	tempDirName, err := ioutil.TempDir("", "clientstore")
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
 	defer os.RemoveAll(tempDirName)
 
 	store, err := NewBoltSwapStore(tempDirName, &chaincfg.MainNetParams)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	// First, verify that an empty database has no active swaps.
 	swaps, err := store.FetchLoopOutSwaps()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(swaps) != 0 {
-		t.Fatal("expected empty store")
-	}
+
+	require.NoError(t, err)
+	require.Empty(t, swaps)
+
+	hash := pendingSwap.Preimage.Hash()
 
 	// checkSwap is a test helper function that'll assert the state of a
 	// swap.
@@ -121,43 +116,37 @@ func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 		t.Helper()
 
 		swaps, err := store.FetchLoopOutSwaps()
-		if err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, err)
 
-		if len(swaps) != 1 {
-			t.Fatal("expected pending swap in store")
-		}
+		require.Len(t, swaps, 1)
 
-		swap := swaps[0].Contract
-		if !reflect.DeepEqual(swap, pendingSwap) {
-			t.Fatal("invalid pending swap data")
-		}
+		swap, err := store.FetchLoopOutSwap(hash)
+		require.NoError(t, err)
 
-		if swaps[0].State().State != expectedState {
-			t.Fatalf("expected state %v, but got %v",
-				expectedState, swaps[0].State(),
-			)
-		}
+		require.Equal(t, hash, swap.Hash)
+		require.Equal(t, hash, swaps[0].Hash)
+
+		swapContract := swap.Contract
+
+		require.Equal(t, swapContract, pendingSwap)
+
+		require.Equal(t, expectedState, swap.State().State)
 
 		if expectedState == StatePreimageRevealed {
-			require.NotNil(t, swaps[0].State().HtlcTxHash)
+			require.NotNil(t, swap.State().HtlcTxHash)
 		}
 	}
 
-	hash := pendingSwap.Preimage.Hash()
-
 	// If we create a new swap, then it should show up as being initialized
 	// right after.
-	if err := store.CreateLoopOut(hash, pendingSwap); err != nil {
-		t.Fatal(err)
-	}
+	err = store.CreateLoopOut(hash, pendingSwap)
+	require.NoError(t, err)
+
 	checkSwap(StateInitiated)
 
 	// Trying to make the same swap again should result in an error.
-	if err := store.CreateLoopOut(hash, pendingSwap); err == nil {
-		t.Fatal("expected error on storing duplicate")
-	}
+	err = store.CreateLoopOut(hash, pendingSwap)
+	require.Error(t, err)
 	checkSwap(StateInitiated)
 
 	// Next, we'll update to the next state of the pre-image being
@@ -169,9 +158,8 @@ func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 			HtlcTxHash: &chainhash.Hash{1, 6, 2},
 		},
 	)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
 	checkSwap(StatePreimageRevealed)
 
 	// Next, we'll update to the final state to ensure that the state is
@@ -182,21 +170,17 @@ func testLoopOutStore(t *testing.T, pendingSwap *LoopOutContract) {
 			State: StateFailInsufficientValue,
 		},
 	)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	checkSwap(StateFailInsufficientValue)
 
-	if err := store.Close(); err != nil {
-		t.Fatal(err)
-	}
+	err = store.Close()
+	require.NoError(t, err)
 
 	// If we re-open the same store, then the state of the current swap
 	// should be the same.
 	store, err = NewBoltSwapStore(tempDirName, &chaincfg.MainNetParams)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
 	checkSwap(StateFailInsufficientValue)
 }
 
@@ -242,24 +226,18 @@ func TestLoopInStore(t *testing.T) {
 
 func testLoopInStore(t *testing.T, pendingSwap LoopInContract) {
 	tempDirName, err := ioutil.TempDir("", "clientstore")
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	defer os.RemoveAll(tempDirName)
 
 	store, err := NewBoltSwapStore(tempDirName, &chaincfg.MainNetParams)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	// First, verify that an empty database has no active swaps.
 	swaps, err := store.FetchLoopInSwaps()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(swaps) != 0 {
-		t.Fatal("expected empty store")
-	}
+	require.NoError(t, err)
+	require.Empty(t, swaps)
+
+	hash := sha256.Sum256(testPreimage[:])
 
 	// checkSwap is a test helper function that'll assert the state of a
 	// swap.
@@ -267,39 +245,27 @@ func testLoopInStore(t *testing.T, pendingSwap LoopInContract) {
 		t.Helper()
 
 		swaps, err := store.FetchLoopInSwaps()
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		if len(swaps) != 1 {
-			t.Fatal("expected pending swap in store")
-		}
+		require.NoError(t, err)
+		require.Len(t, swaps, 1)
 
 		swap := swaps[0].Contract
-		if !reflect.DeepEqual(swap, &pendingSwap) {
-			t.Fatal("invalid pending swap data")
-		}
 
-		if swaps[0].State().State != expectedState {
-			t.Fatalf("expected state %v, but got %v",
-				expectedState, swaps[0].State(),
-			)
-		}
-	}
+		require.Equal(t, swap, &pendingSwap)
 
-	hash := sha256.Sum256(testPreimage[:])
+		require.Equal(t, swaps[0].State().State, expectedState)
+	}
 
 	// If we create a new swap, then it should show up as being initialized
 	// right after.
-	if err := store.CreateLoopIn(hash, &pendingSwap); err != nil {
-		t.Fatal(err)
-	}
+	err = store.CreateLoopIn(hash, &pendingSwap)
+	require.NoError(t, err)
+
 	checkSwap(StateInitiated)
 
 	// Trying to make the same swap again should result in an error.
-	if err := store.CreateLoopIn(hash, &pendingSwap); err == nil {
-		t.Fatal("expected error on storing duplicate")
-	}
+	err = store.CreateLoopIn(hash, &pendingSwap)
+	require.Error(t, err)
+
 	checkSwap(StateInitiated)
 
 	// Next, we'll update to the next state of the pre-image being
@@ -310,9 +276,8 @@ func testLoopInStore(t *testing.T, pendingSwap LoopInContract) {
 			State: StatePreimageRevealed,
 		},
 	)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
 	checkSwap(StatePreimageRevealed)
 
 	// Next, we'll update to the final state to ensure that the state is
@@ -323,21 +288,17 @@ func testLoopInStore(t *testing.T, pendingSwap LoopInContract) {
 			State: StateFailInsufficientValue,
 		},
 	)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	checkSwap(StateFailInsufficientValue)
 
-	if err := store.Close(); err != nil {
-		t.Fatal(err)
-	}
+	err = store.Close()
+	require.NoError(t, err)
 
 	// If we re-open the same store, then the state of the current swap
 	// should be the same.
 	store, err = NewBoltSwapStore(tempDirName, &chaincfg.MainNetParams)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
 	checkSwap(StateFailInsufficientValue)
 }
 
@@ -467,9 +428,8 @@ func TestLegacyOutgoingChannel(t *testing.T) {
 
 	// Assert that the outgoing channel is read properly.
 	expectedChannelSet := ChannelSet{5}
-	if !reflect.DeepEqual(swaps[0].Contract.OutgoingChanSet, expectedChannelSet) {
-		t.Fatal("invalid outgoing channel")
-	}
+
+	require.Equal(t, expectedChannelSet, swaps[0].Contract.OutgoingChanSet)
 }
 
 // TestLiquidityParams checks that reading and writing to liquidty bucket are

store_mock_test.go

@@ -70,6 +70,36 @@ func (s *storeMock) FetchLoopOutSwaps() ([]*loopdb.LoopOut, error) {
 	return result, nil
 }
 
+// FetchLoopOutSwaps returns all swaps currently in the store.
+//
+// NOTE: Part of the loopdb.SwapStore interface.
+func (s *storeMock) FetchLoopOutSwap(
+	hash lntypes.Hash) (*loopdb.LoopOut, error) {
+
+	contract, ok := s.loopOutSwaps[hash]
+	if !ok {
+		return nil, errors.New("swap not found")
+	}
+
+	updates := s.loopOutUpdates[hash]
+	events := make([]*loopdb.LoopEvent, len(updates))
+	for i, u := range updates {
+		events[i] = &loopdb.LoopEvent{
+			SwapStateData: u,
+		}
+	}
+
+	swap := &loopdb.LoopOut{
+		Loop: loopdb.Loop{
+			Hash:   hash,
+			Events: events,
+		},
+		Contract: contract,
+	}
+
+	return swap, nil
+}
+
 // CreateLoopOut adds an initiated swap to the store.
 //
 // NOTE: Part of the loopdb.SwapStore interface.