loopout: use the request defined payment timeout

Author: bhandras

interface.go

@@ -92,6 +92,12 @@ type OutRequest struct {
 	// initiated the swap (loop CLI, autolooper, LiT UI and so on) and is
 	// appended to the user agent string.
 	Initiator string
+
+	// PaymentTimeout specifies the payment timeout for the individual
+	// off-chain payments. As the swap payment may be retried (depending on
+	// the configured maximum payment timeout) the total time spent may be
+	// a multiple of this value.
+	PaymentTimeout time.Duration
 }
 
 // Out contains the full details of a loop out request. This includes things

loopd/swapclient_server.go

@@ -101,6 +101,17 @@ func (s *swapClientServer) LoopOut(ctx context.Context,
 
 	log.Infof("Loop out request received")
 
+	// Note that LoopOutRequest.PaymentTimeout is unsigned and therefore
+	// cannot be negative.
+	paymentTimeout := time.Duration(in.PaymentTimeout) * time.Second
+
+	// Make sure we don't exceed the total allowed payment timeout.
+	if paymentTimeout > s.config.TotalPaymentTimeout {
+		return nil, fmt.Errorf("payment timeout %v exceeds maximum "+
+			"allowed timeout of %v", paymentTimeout,
+			s.config.TotalPaymentTimeout)
+	}
+
 	var sweepAddr btcutil.Address
 	var isExternalAddr bool
 	var err error
@@ -184,6 +195,7 @@ func (s *swapClientServer) LoopOut(ctx context.Context,
 		SwapPublicationDeadline: publicationDeadline,
 		Label:                   in.Label,
 		Initiator:               in.Initiator,
+		PaymentTimeout:          paymentTimeout,
 	}
 
 	switch {

loopout.go

@@ -195,6 +195,7 @@ func newLoopOutSwap(globalCtx context.Context, cfg *swapConfig,
 			ProtocolVersion: loopdb.CurrentProtocolVersion(),
 		},
 		OutgoingChanSet: chanSet,
+		PaymentTimeout:  request.PaymentTimeout,
 	}
 
 	swapKit := newSwapKit(
@@ -610,7 +611,8 @@ func (s *loopOutSwap) payInvoices(ctx context.Context) {
 	// Use the recommended routing plugin.
 	s.swapPaymentChan = s.payInvoice(
 		ctx, s.SwapInvoice, s.MaxSwapRoutingFee,
-		s.LoopOutContract.OutgoingChanSet, pluginType, true,
+		s.LoopOutContract.OutgoingChanSet,
+		s.LoopOutContract.PaymentTimeout, pluginType, true,
 	)
 
 	// Pay the prepay invoice. Won't use the routing plugin here as the
@@ -619,7 +621,8 @@ func (s *loopOutSwap) payInvoices(ctx context.Context) {
 	s.log.Infof("Sending prepayment %v", s.PrepayInvoice)
 	s.prePaymentChan = s.payInvoice(
 		ctx, s.PrepayInvoice, s.MaxPrepayRoutingFee,
-		s.LoopOutContract.OutgoingChanSet, RoutingPluginNone, false,
+		s.LoopOutContract.OutgoingChanSet,
+		s.LoopOutContract.PaymentTimeout, RoutingPluginNone, false,
 	)
 }
 
@@ -647,7 +650,7 @@ func (p paymentResult) failure() error {
 // payInvoice pays a single invoice.
 func (s *loopOutSwap) payInvoice(ctx context.Context, invoice string,
 	maxFee btcutil.Amount, outgoingChanIds loopdb.ChannelSet,
-	pluginType RoutingPluginType,
+	paymentTimeout time.Duration, pluginType RoutingPluginType,
 	reportPluginResult bool) chan paymentResult {
 
 	resultChan := make(chan paymentResult)
@@ -662,8 +665,8 @@ func (s *loopOutSwap) payInvoice(ctx context.Context, invoice string,
 		var result paymentResult
 
 		status, err := s.payInvoiceAsync(
-			ctx, invoice, maxFee, outgoingChanIds, pluginType,
-			reportPluginResult,
+			ctx, invoice, maxFee, outgoingChanIds, paymentTimeout,
+			pluginType, reportPluginResult,
 		)
 		if err != nil {
 			result.err = err
@@ -691,8 +694,9 @@ func (s *loopOutSwap) payInvoice(ctx context.Context, invoice string,
 // payInvoiceAsync is the asynchronously executed part of paying an invoice.
 func (s *loopOutSwap) payInvoiceAsync(ctx context.Context,
 	invoice string, maxFee btcutil.Amount,
-	outgoingChanIds loopdb.ChannelSet, pluginType RoutingPluginType,
-	reportPluginResult bool) (*lndclient.PaymentStatus, error) {
+	outgoingChanIds loopdb.ChannelSet, paymentTimeout time.Duration,
+	pluginType RoutingPluginType, reportPluginResult bool) (
+	*lndclient.PaymentStatus, error) {
 
 	// Extract hash from payment request. Unfortunately the request
 	// components aren't available directly.
@@ -705,7 +709,7 @@ func (s *loopOutSwap) payInvoiceAsync(ctx context.Context,
 	}
 
 	maxRetries := 1
-	paymentTimeout := s.executeConfig.totalPaymentTimeout
+	totalPaymentTimeout := s.executeConfig.totalPaymentTimeout
 
 	// Attempt to acquire and initialize the routing plugin.
 	routingPlugin, err := AcquireRoutingPlugin(
@@ -720,8 +724,30 @@ func (s *loopOutSwap) payInvoiceAsync(ctx context.Context,
 			pluginType, hash.String())
 
 		maxRetries = s.executeConfig.maxPaymentRetries
-		paymentTimeout /= time.Duration(maxRetries)
+
+		// If not set, default to the per payment timeout to the total
+		// payment timeout divied by the configured maximum retries.
+		if paymentTimeout == 0 {
+			paymentTimeout = totalPaymentTimeout /
+				time.Duration(maxRetries)
+		}
+
+		// If the payment timeout is too long, we need to adjust the
+		// number of retries to ensure we don't exceed the total
+		// payment timeout.
+		if paymentTimeout*time.Duration(maxRetries) >
+			totalPaymentTimeout {
+
+			maxRetries = int(totalPaymentTimeout / paymentTimeout)
+			s.log.Infof("Adjusted max routing plugin retries to "+
+				"%v to stay within total payment timeout",
+				maxRetries)
+		}
 		defer ReleaseRoutingPlugin(ctx)
+	} else if paymentTimeout == 0 {
+		// If not set, default the payment timeout to the total payment
+		// timeout.
+		paymentTimeout = totalPaymentTimeout
 	}
 
 	req := lndclient.SendPaymentRequest{