loopd+lsat: add LSAT cost configuration parameters

Author: guggero

loopd/config.go

@@ -4,6 +4,7 @@ import (
 	"path/filepath"
 
 	"github.com/btcsuite/btcutil"
+	"github.com/lightninglabs/loop/lsat"
 )
 
 var (
@@ -39,7 +40,9 @@ type config struct {
 	MaxLogFiles    int    `long:"maxlogfiles" description:"Maximum logfiles to keep (0 for no rotation)"`
 	MaxLogFileSize int    `long:"maxlogfilesize" description:"Maximum logfile size in MB"`
 
-	DebugLevel string `short:"d" long:"debuglevel" description:"Logging level for all subsystems {trace, debug, info, warn, error, critical} -- You may also specify <subsystem>=<level>,<subsystem2>=<level>,... to set the log level for individual subsystems -- Use show to list available subsystems"`
+	DebugLevel  string `short:"d" long:"debuglevel" description:"Logging level for all subsystems {trace, debug, info, warn, error, critical} -- You may also specify <subsystem>=<level>,<subsystem2>=<level>,... to set the log level for individual subsystems -- Use show to list available subsystems"`
+	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."`
 
 	Lnd *lndConfig `group:"lnd" namespace:"lnd"`
 
@@ -60,6 +63,8 @@ var defaultConfig = config{
 	MaxLogFiles:    defaultMaxLogFiles,
 	MaxLogFileSize: defaultMaxLogFileSize,
 	DebugLevel:     defaultLogLevel,
+	MaxLSATCost:    lsat.DefaultMaxCostSats,
+	MaxLSATFee:     lsat.DefaultMaxRoutingFeeSats,
 	Lnd: &lndConfig{
 		Host: "localhost:10009",
 	},

lsat/interceptor.go

@@ -33,10 +33,14 @@ const (
 	// challenge.
 	AuthHeader = "WWW-Authenticate"
 
-	// MaxRoutingFee is the maximum routing fee in satoshis that we are
-	// going to pay to acquire an LSAT token.
-	// TODO(guggero): make this configurable
-	MaxRoutingFeeSats = 10
+	// DefaultMaxCostSats is the default maximum amount in satoshis that we
+	// are going to pay for an LSAT automatically. Does not include routing
+	// fees.
+	DefaultMaxCostSats = 1000
+
+	// DefaultMaxRoutingFeeSats is the default maximum routing fee in
+	// satoshis that we are going to pay to acquire an LSAT token.
+	DefaultMaxRoutingFeeSats = 10
 
 	// PaymentTimeout is the maximum time we allow a payment to take before
 	// we stop waiting for it.
@@ -238,7 +242,7 @@ func (i *Interceptor) payLsatToken(ctx context.Context, md *metadata.MD) (
 	payCtx, cancel := context.WithTimeout(ctx, PaymentTimeout)
 	defer cancel()
 	respChan := i.lnd.Client.PayInvoice(
-		payCtx, invoiceStr, MaxRoutingFeeSats, nil,
+		payCtx, invoiceStr, DefaultMaxRoutingFeeSats, nil,
 	)
 	select {
 	case result := <-respChan: