Add fee limit ppm

main.go

@@ -32,6 +32,7 @@ var params struct {
 	Perc               int64    `short:"p" long:"perc" description:"use this value as both pfrom and pto from above" json:"perc"`
 	Amount             int64    `short:"a" long:"amount" description:"amount to rebalance" json:"amount"`
 	EconRatio          float64  `short:"r" long:"econ-ratio" description:"economical ratio for fee limit calculation as a multiple of target channel fee (for example, 0.5 means you want to pay at max half the fee you might earn for routing out of the target channel)" json:"econ_ratio" toml:"econ_ratio"`
+	FeeLimitPPM        int64    `short:"F" long:"fee-limit-ppm" description:"don't consider the target channel fee and use this max fee ppm instead (can rebalance at a loss, be careful)" json:"fee_limit_ppm" toml:"fee_limit_ppm"`
 	LostProfit         bool     `short:"l" long:"lost-profit" description:"also consider the outbound channel fees when looking for profitable routes so that outbound_fee+inbound_fee < route_fee" json:"lost_profit" toml:"lost_profit"`
 	ProbeSteps         int      `short:"b" long:"probe-steps" description:"if the payment fails at the last hop try to probe lower amount using this many steps" json:"probe_steps" toml:"probe_steps"`
 	MinAmount          int64    `long:"min-amount" description:"if probing is enabled this will be the minimum amount to try" json:"min_amount" toml:"min_amount"`
@@ -177,7 +178,7 @@ func main() {
 	if params.ToPerc == 0 {
 		params.ToPerc = 50
 	}
-	if params.EconRatio == 0 {
+	if params.EconRatio == 0 && params.FeeLimitPPM == 0 {
 		params.EconRatio = 1
 	}
 	if params.Perc > 0 {

routes.go

@@ -28,7 +28,21 @@ func (r *regolancer) getChanInfo(ctx context.Context, chanId uint64) (*lnrpc.Cha
 	return c, nil
 }
 
-func (r *regolancer) calcFeeMsat(ctx context.Context, from, to uint64, amtMsat int64, ratio float64) (feeMsat int64,
+func (r *regolancer) calcFeeLimitMsat(ctx context.Context, to uint64,
+	amtMsat int64, ppm int64) (feeMsat int64, lastPKstr string, err error) {
+	cTo, err := r.getChanInfo(ctx, to)
+	if err != nil {
+		return 0, "", err
+	}
+	lastPKstr = cTo.Node1Pub
+	if lastPKstr == r.myPK {
+		lastPKstr = cTo.Node2Pub
+	}
+	feeMsat = amtMsat * ppm / 1e6
+	return
+}
+
+func (r *regolancer) calcEconFeeMsat(ctx context.Context, from, to uint64, amtMsat int64, ratio float64) (feeMsat int64,
 	lastPKstr string, err error) {
 	cTo, err := r.getChanInfo(ctx, to)
 	if err != nil {
@@ -61,6 +75,15 @@ func (r *regolancer) calcFeeMsat(ctx context.Context, from, to uint64, amtMsat i
 	return
 }
 
+func (r *regolancer) calcFeeMsat(ctx context.Context, from, to uint64,
+	amtMsat int64, ratio float64) (feeMsat int64, lastPKstr string, err error) {
+	if params.FeeLimitPPM > 0 {
+		return r.calcFeeLimitMsat(ctx, to, amtMsat, params.FeeLimitPPM)
+	} else {
+		return r.calcEconFeeMsat(ctx, from, to, amtMsat, params.EconRatio)
+	}
+}
+
 func (r *regolancer) getRoutes(ctx context.Context, from, to uint64, amtMsat int64) ([]*lnrpc.Route, int64, error) {
 	routeCtx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()