loopd: make maximum number of payment parts configurable

client.go

@@ -108,6 +108,11 @@ type ClientConfig struct {
 	// MaxLsatFee is the maximum that we are willing to pay in routing fees
 	// to obtain the token.
 	MaxLsatFee btcutil.Amount
+
+	// LoopOutMaxParts defines the maximum number of parts that may be used
+	// for a loop out swap. When greater than one, a multi-part payment may
+	// be attempted.
+	LoopOutMaxParts uint32
 }
 
 // NewClient returns a new instance to initiate swaps with.
@@ -145,6 +150,7 @@ func NewClient(dbDir string, cfg *ClientConfig) (*Client, func(), error) {
 		store:             store,
 		sweeper:           sweeper,
 		createExpiryTimer: config.CreateExpiryTimer,
+		loopOutMaxParts:   cfg.LoopOutMaxParts,
 	})
 
 	client := &Client{

executor.go

@@ -22,6 +22,8 @@ type executorConfig struct {
 	store loopdb.SwapStore
 
 	createExpiryTimer func(expiry time.Duration) <-chan time.Time
+
+	loopOutMaxParts uint32
 }
 
 // executor is responsible for executing swaps.
@@ -109,10 +111,11 @@ func (s *executor) run(mainCtx context.Context,
 				defer s.wg.Done()
 
 				newSwap.execute(mainCtx, &executeConfig{
-					statusChan:     statusChan,
-					sweeper:        s.sweeper,
-					blockEpochChan: queue.ChanOut(),
-					timerFactory:   s.executorConfig.createExpiryTimer,
+					statusChan:      statusChan,
+					sweeper:         s.sweeper,
+					blockEpochChan:  queue.ChanOut(),
+					timerFactory:    s.executorConfig.createExpiryTimer,
+					loopOutMaxParts: s.executorConfig.loopOutMaxParts,
 				}, height)
 
 				select {

loopd/config.go

@@ -15,8 +15,9 @@ var (
 	defaultLogFilename = "loopd.log"
 	defaultLogDir      = filepath.Join(loopDirBase, defaultLogDirname)
 
-	defaultMaxLogFiles    = 3
-	defaultMaxLogFileSize = 10
+	defaultMaxLogFiles     = 3
+	defaultMaxLogFileSize  = 10
+	defaultLoopOutMaxParts = uint32(5)
 )
 
 type lndConfig struct {
@@ -45,6 +46,8 @@ type config struct {
 	MaxLSATCost uint32 `long:"maxlsatcost" description:"Maximum cost in satoshis that loopd is going to pay for an LSAT token automatically. Does not include routing fees."`
 	MaxLSATFee  uint32 `long:"maxlsatfee" description:"Maximum routing fee in satoshis that we are willing to pay while paying for an LSAT token."`
 
+	LoopOutMaxParts uint32 `long:"loopoutmaxparts" description:"The maximum number of payment parts that may be used for a loop out swap."`
+
 	Lnd   *lndConfig `group:"lnd" namespace:"lnd"`
 	Proxy string     `long:"proxy" description:"The host:port of a SOCKS proxy through which all connections to the swap server will be established over."`
 
@@ -57,16 +60,17 @@ const (
 )
 
 var defaultConfig = config{
-	Network:        "mainnet",
-	RPCListen:      "localhost:11010",
-	RESTListen:     "localhost:8081",
-	Insecure:       false,
-	LogDir:         defaultLogDir,
-	MaxLogFiles:    defaultMaxLogFiles,
-	MaxLogFileSize: defaultMaxLogFileSize,
-	DebugLevel:     defaultLogLevel,
-	MaxLSATCost:    lsat.DefaultMaxCostSats,
-	MaxLSATFee:     lsat.DefaultMaxRoutingFeeSats,
+	Network:         "mainnet",
+	RPCListen:       "localhost:11010",
+	RESTListen:      "localhost:8081",
+	Insecure:        false,
+	LogDir:          defaultLogDir,
+	MaxLogFiles:     defaultMaxLogFiles,
+	MaxLogFileSize:  defaultMaxLogFileSize,
+	DebugLevel:      defaultLogLevel,
+	MaxLSATCost:     lsat.DefaultMaxCostSats,
+	MaxLSATFee:      lsat.DefaultMaxRoutingFeeSats,
+	LoopOutMaxParts: defaultLoopOutMaxParts,
 	Lnd: &lndConfig{
 		Host: "localhost:10009",
 	},

loopout.go

@@ -45,12 +45,6 @@ var (
 	paymentTimeout = time.Minute
 )
 
-const (
-	// loopOutMaxShards defines that maximum number of shards that may be
-	// used for a loop out swap.
-	loopOutMaxShards = 5
-)
-
 // loopOutSwap contains all the in-memory state related to a pending loop out
 // swap.
 type loopOutSwap struct {
@@ -64,10 +58,11 @@ type loopOutSwap struct {
 
 // executeConfig contains extra configuration to execute the swap.
 type executeConfig struct {
-	sweeper        *sweep.Sweeper
-	statusChan     chan<- SwapInfo
-	blockEpochChan <-chan interface{}
-	timerFactory   func(d time.Duration) <-chan time.Time
+	sweeper         *sweep.Sweeper
+	statusChan      chan<- SwapInfo
+	blockEpochChan  <-chan interface{}
+	timerFactory    func(d time.Duration) <-chan time.Time
+	loopOutMaxParts uint32
 }
 
 // newLoopOutSwap initiates a new swap with the server and returns a
@@ -462,7 +457,7 @@ func (s *loopOutSwap) payInvoiceAsync(ctx context.Context,
 		Invoice:         invoice,
 		OutgoingChannel: outgoingChannel,
 		Timeout:         paymentTimeout,
-		MaxParts:        loopOutMaxShards,
+		MaxParts:        s.executeConfig.loopOutMaxParts,
 	}
 
 	// Lookup state of the swap payment.