instantout: add instantout manager

Author: sputn1ck

instantout/manager.go

@@ -0,0 +1,201 @@
+package instantout
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/lightninglabs/loop/instantout/reservation"
+	"github.com/lightningnetwork/lnd/lntypes"
+)
+
+var (
+	defaultStateWaitTime = 30 * time.Second
+	defaultCltv          = 100
+	ErrSwapDoesNotExist  = errors.New("swap does not exist")
+)
+
+// Manager manages the instantout state machines.
+type Manager struct {
+	// cfg contains all the services that the reservation manager needs to
+	// operate.
+	cfg *Config
+
+	// activeInstantOuts contains all the active instantouts.
+	activeInstantOuts map[lntypes.Hash]*FSM
+
+	// currentHeight stores the currently best known block height.
+	currentHeight int32
+
+	// blockEpochChan receives new block heights.
+	blockEpochChan chan int32
+
+	runCtx context.Context
+
+	sync.Mutex
+}
+
+// NewInstantOutManager creates a new instantout manager.
+func NewInstantOutManager(cfg *Config) *Manager {
+	return &Manager{
+		cfg:               cfg,
+		activeInstantOuts: make(map[lntypes.Hash]*FSM),
+		blockEpochChan:    make(chan int32),
+	}
+}
+
+// Run runs the instantout manager.
+func (m *Manager) Run(ctx context.Context, initChan chan struct{},
+	height int32) error {
+
+	log.Debugf("Starting instantout manager")
+	defer func() {
+		log.Debugf("Stopping instantout manager")
+	}()
+
+	runCtx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	m.runCtx = runCtx
+	m.currentHeight = height
+
+	err := m.recoverInstantOuts(runCtx)
+	if err != nil {
+		close(initChan)
+		return err
+	}
+
+	newBlockChan, newBlockErrChan, err := m.cfg.ChainNotifier.
+		RegisterBlockEpochNtfn(ctx)
+	if err != nil {
+		close(initChan)
+		return err
+	}
+
+	close(initChan)
+
+	for {
+		select {
+		case <-runCtx.Done():
+			return nil
+
+		case height := <-newBlockChan:
+			m.Lock()
+			m.currentHeight = height
+			m.Unlock()
+
+		case err := <-newBlockErrChan:
+			return err
+		}
+	}
+}
+
+// recoverInstantOuts recovers all the active instantouts from the database.
+func (m *Manager) recoverInstantOuts(ctx context.Context) error {
+	// Fetch all the active instantouts from the database.
+	activeInstantOuts, err := m.cfg.Store.ListInstantLoopOuts(ctx)
+	if err != nil {
+		return err
+	}
+
+	for _, instantOut := range activeInstantOuts {
+		if isFinalState(instantOut.State) {
+			continue
+		}
+
+		log.Debugf("Recovering instantout %v", instantOut.SwapHash)
+
+		instantOutFSM, err := NewFSMFromInstantOut(
+			ctx, m.cfg, instantOut,
+		)
+		if err != nil {
+			return err
+		}
+
+		m.activeInstantOuts[instantOut.SwapHash] = instantOutFSM
+
+		// As SendEvent can block, we'll start a goroutine to process
+		// the event.
+		go func() {
+			err := instantOutFSM.SendEvent(OnRecover, nil)
+			if err != nil {
+				log.Errorf("FSM %v Error sending recover "+
+					"event %v, state: %v",
+					instantOutFSM.InstantOut.SwapHash, err,
+					instantOutFSM.InstantOut.State)
+			}
+		}()
+	}
+
+	return nil
+}
+
+// NewInstantOut creates a new instantout.
+func (m *Manager) NewInstantOut(ctx context.Context,
+	reservations []reservation.ID) (*FSM, error) {
+
+	m.Lock()
+	// Create the instantout request.
+	request := &InitInstantOutCtx{
+		cltvExpiry:      m.currentHeight + int32(defaultCltv),
+		reservations:    reservations,
+		initationHeight: m.currentHeight,
+		protocolVersion: CurrentProtocolVersion(),
+	}
+
+	instantOut, err := NewFSM(
+		m.runCtx, m.cfg, ProtocolVersionFullReservation,
+	)
+	if err != nil {
+		m.Unlock()
+		return nil, err
+	}
+	m.activeInstantOuts[instantOut.InstantOut.SwapHash] = instantOut
+	m.Unlock()
+
+	// Start the instantout FSM.
+	go func() {
+		err := instantOut.SendEvent(OnStart, request)
+		if err != nil {
+			log.Errorf("Error sending event: %v", err)
+		}
+	}()
+
+	// If everything went well, we'll wait for the instant out to be
+	// waiting for sweepless sweep to be confirmed.
+	err = instantOut.DefaultObserver.WaitForState(
+		ctx, defaultStateWaitTime, WaitForSweeplessSweepConfirmed,
+	)
+	if err != nil {
+		if instantOut.LastActionError != nil {
+			return instantOut, fmt.Errorf(
+				"error waiting for sweepless sweep "+
+					"confirmed: %w", instantOut.LastActionError,
+			)
+		}
+		return instantOut, nil
+	}
+
+	return instantOut, nil
+}
+
+// GetActiveInstantOut returns an active instant out.
+func (m *Manager) GetActiveInstantOut(swapHash lntypes.Hash) (*FSM, error) {
+	m.Lock()
+	defer m.Unlock()
+
+	fsm, ok := m.activeInstantOuts[swapHash]
+	if !ok {
+		return nil, ErrSwapDoesNotExist
+	}
+
+	// If the instant out is in a final state, we'll remove it from the
+	// active instant outs.
+	if isFinalState(fsm.InstantOut.State) {
+		delete(m.activeInstantOuts, swapHash)
+	}
+
+	return fsm, nil
+}

instantout/reservation/manager.go

@@ -23,6 +23,8 @@ type Manager struct {
 	// activeReservations contains all the active reservationsFSMs.
 	activeReservations map[ID]*FSM
 
+	runCtx context.Context
+
 	sync.Mutex
 }
 
@@ -41,6 +43,7 @@ func (m *Manager) Run(ctx context.Context, height int32) error {
 	runCtx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
+	m.runCtx = runCtx
 	currentHeight := height
 
 	err := m.RecoverReservations(runCtx)
@@ -58,7 +61,7 @@ func (m *Manager) Run(ctx context.Context, height int32) error {
 		chan *reservationrpc.ServerReservationNotification,
 	)
 
-	err = m.RegisterReservationNotifications(runCtx, reservationResChan)
+	err = m.RegisterReservationNotifications(reservationResChan)
 	if err != nil {
 		return err
 	}
@@ -155,25 +158,29 @@ func (m *Manager) newReservation(ctx context.Context, currentHeight uint32,
 // RegisterReservationNotifications registers a new reservation notification
 // stream.
 func (m *Manager) RegisterReservationNotifications(
-	ctx context.Context, reservationChan chan *reservationrpc.
-		ServerReservationNotification) error {
+	reservationChan chan *reservationrpc.ServerReservationNotification) error {
 
 	// In order to create a valid lsat we first are going to call
 	// the FetchL402 method.
-	err := m.cfg.FetchL402(ctx)
+	err := m.cfg.FetchL402(m.runCtx)
 	if err != nil {
 		return err
 	}
 
+	ctx, cancel := context.WithCancel(m.runCtx)
+
 	// We'll now subscribe to the reservation notifications.
 	reservationStream, err := m.cfg.ReservationClient.
 		ReservationNotificationStream(
 			ctx, &reservationrpc.ReservationNotificationRequest{},
 		)
 	if err != nil {
+		cancel()
 		return err
 	}
 
+	log.Debugf("Successfully subscribed to reservation notifications")
+
 	// We'll now start a goroutine that will forward all the reservation
 	// notifications to the reservationChan.
 	go func() {
@@ -188,36 +195,30 @@ func (m *Manager) RegisterReservationNotifications(
 			log.Errorf("Error receiving "+
 				"reservation: %v", err)
 
-			reconnectTimer := time.NewTimer(time.Second * 10)
+			cancel()
 
 			// If we encounter an error, we'll
 			// try to reconnect.
 			for {
 				select {
-				case <-ctx.Done():
+				case <-m.runCtx.Done():
 					return
-				case <-reconnectTimer.C:
+
+				case <-time.After(time.Second * 10):
+					log.Debugf("Reconnecting to " +
+						"reservation notifications")
 					err = m.RegisterReservationNotifications(
-						ctx, reservationChan,
+						reservationChan,
 					)
-					if err == nil {
-						log.Debugf(
-							"Successfully " +
-								"reconnected",
-						)
-						reconnectTimer.Stop()
-						// If we were able to
-						// reconnect, we'll
-						// return.
-						return
+					if err != nil {
+						log.Errorf("Error "+
+							"reconnecting: %v", err)
+						continue
 					}
-					log.Errorf("Error "+
-						"reconnecting: %v",
-						err)
 
-					reconnectTimer.Reset(
-						time.Second * 10,
-					)
+					// If we were able to reconnect, we'll
+					// return.
+					return
 				}
 			}
 		}