cmd/lncli: add fee limit flags to routing related commands

cmd/lncli/commands.go

@@ -103,37 +103,6 @@ func actionDecorator(f func(*cli.Context) error) func(*cli.Context) error {
 	}
 }
 
-// calculateFeeLimit takes ctx and the amount for the payment in satoshis.
-// It checks the fee_limit and fee_limit_percent flags and determines the
-// the feeLimit based on those values. If both flags are set, calculateFeeLimit
-// sets feeLimit to the Minumum value between them. If neither flag is set,
-// feeLimit is set to the maximum int64 value as to avoid enforcing a limit.
-func calculateFeeLimit(ctx *cli.Context, amount int64) int64 {
-	var (
-		feeLimit        int64
-		feeLimitPercent int64
-	)
-
-	const MaxInt64Value int64 = 1<<63 - 1 // 9223372036854775807
-	feeLimit = MaxInt64Value
-
-	if ctx.IsSet("fee_limit_percent") {
-		feeRatio := float64(ctx.Int64("fee_limit_percent")) / 100
-		feeLimitPercent = int64(float64(amount) * feeRatio)
-		feeLimit = feeLimitPercent
-	}
-
-	if ctx.IsSet("fee_limit") {
-		feeLimit = ctx.Int64("fee_limit")
-	}
-
-	// If both fee_limit and fee_limit_percent are set, pick the minimum
-	if ctx.IsSet("fee_limit") && ctx.IsSet("fee_limit_percent") {
-		feeLimit = int64(math.Min(float64(feeLimit), float64(feeLimitPercent)))
-	}
-	return feeLimit
-}
-
 var newAddressCommand = cli.Command{
 	Name:      "newaddress",
 	Category:  "Wallet",
@@ -1648,6 +1617,16 @@ var sendPaymentCommand = cli.Command{
 			Name:  "amt, a",
 			Usage: "number of satoshis to send",
 		},
+		cli.Int64Flag{
+			Name: "fee_limit",
+			Usage: "maximum fee allowed in satoshis when sending" +
+				"the payment",
+		},
+		cli.Int64Flag{
+			Name: "fee_limit_percent",
+			Usage: "percentage of the payment's amount used as the" +
+				"maximum fee allowed when sending the payment",
+		},
 		cli.StringFlag{
 			Name:  "payment_hash, r",
 			Usage: "the hash to use within the payment's HTLC",
@@ -1664,18 +1643,36 @@ var sendPaymentCommand = cli.Command{
 			Name:  "final_cltv_delta",
 			Usage: "the number of blocks the last hop has to reveal the preimage",
 		},
-		cli.Int64Flag{
-			Name:  "fee_limit",
-			Usage: "maximum total fees for the payment in satoshis",
-		},
-		cli.Int64Flag{
-			Name:  "fee_limit_percent",
-			Usage: "maximum total fees as a percentage of amt",
-		},
 	},
 	Action: sendPayment,
 }
 
+// retrieveFeeLimit retrieves the fee limit based on the different fee limit
+// flags passed.
+func retrieveFeeLimit(ctx *cli.Context) (*lnrpc.FeeLimit, error) {
+	switch {
+	case ctx.IsSet("fee_limit") && ctx.IsSet("fee_limit_percent"):
+		return nil, fmt.Errorf("either fee_limit or fee_limit_percent " +
+			"can be set, but not both")
+	case ctx.IsSet("fee_limit"):
+		return &lnrpc.FeeLimit{
+			Limit: &lnrpc.FeeLimit_Fixed{
+				Fixed: ctx.Int64("fee_limit"),
+			},
+		}, nil
+	case ctx.IsSet("fee_limit_percent"):
+		return &lnrpc.FeeLimit{
+			Limit: &lnrpc.FeeLimit_Percent{
+				Percent: ctx.Int64("fee_limit_percent"),
+			},
+		}, nil
+	}
+
+	// Since the fee limit flags aren't required, we don't return an error
+	// if they're not set.
+	return nil, nil
+}
+
 func sendPayment(ctx *cli.Context) error {
 	// Show command help if no arguments provided
 	if ctx.NArg() == 0 && ctx.NumFlags() == 0 {
@@ -1683,22 +1680,33 @@ func sendPayment(ctx *cli.Context) error {
 		return nil
 	}
 
-	var req *lnrpc.SendRequest
+	// First, we'll retrieve the fee limit value passed since it can apply
+	// to both ways of sending payments (with the payment request or
+	// providing the details manually).
+	feeLimit, err := retrieveFeeLimit(ctx)
+	if err != nil {
+		return err
+	}
+
+	// If a payment request was provided, we can exit early since all of the
+	// details of the payment are encoded within the request.
 	if ctx.IsSet("pay_req") {
-		req = &lnrpc.SendRequest{
+		req := &lnrpc.SendRequest{
 			PaymentRequest: ctx.String("pay_req"),
 			Amt:            ctx.Int64("amt"),
+			FeeLimit:       feeLimit,
+		}
+
+		return sendPaymentRequest(ctx, req)
 	}
-	} else {
-		args := ctx.Args()
 
 	var (
 		destNode []byte
-			err      error
 		amount   int64
-			feeLimit int64
 	)
 
+	args := ctx.Args()
+
 	switch {
 	case ctx.IsSet("dest"):
 		destNode, err = hex.DecodeString(ctx.String("dest"))
@@ -1727,9 +1735,7 @@ func sendPayment(ctx *cli.Context) error {
 		}
 	}
 
-		feeLimit = calculateFeeLimit(ctx, amount)
+	req := &lnrpc.SendRequest{
-
-		req = &lnrpc.SendRequest{
 		Dest:     destNode,
 		Amt:      amount,
 		FeeLimit: feeLimit,
@@ -1769,7 +1775,6 @@ func sendPayment(ctx *cli.Context) error {
 			req.FinalCltvDelta = int32(delta)
 		}
 	}
-	}
 
 	return sendPaymentRequest(ctx, req)
 }
@@ -1824,11 +1829,13 @@ var payInvoiceCommand = cli.Command{
 		},
 		cli.Int64Flag{
 			Name: "fee_limit",
-			Usage: "maximum total fees for the payment in satoshis",
+			Usage: "maximum fee allowed in satoshis when sending" +
+				"the payment",
 		},
 		cli.Int64Flag{
 			Name: "fee_limit_percent",
-			Usage: "maximum total fees as a percentage of amt",
+			Usage: "percentage of the payment's amount used as the" +
+				"maximum fee allowed when sending the payment",
 		},
 	},
 	Action: actionDecorator(payInvoice),
@@ -1838,9 +1845,6 @@ func payInvoice(ctx *cli.Context) error {
 	args := ctx.Args()
 
 	var payReq string
-	var feeLimit int64
-	var amt int64
-
 	switch {
 	case ctx.IsSet("pay_req"):
 		payReq = ctx.String("pay_req")
@@ -1850,13 +1854,14 @@ func payInvoice(ctx *cli.Context) error {
 		return fmt.Errorf("pay_req argument missing")
 	}
 
-	amt = ctx.Int64("amt")
+	feeLimit, err := retrieveFeeLimit(ctx)
-
+	if err != nil {
-	feeLimit = calculateFeeLimit(ctx, amt)
+		return err
+	}
 
 	req := &lnrpc.SendRequest{
 		PaymentRequest: payReq,
-		Amt:            amt,
+		Amt:            ctx.Int64("amt"),
 		FeeLimit:       feeLimit,
 	}
 
@@ -2559,11 +2564,13 @@ var queryRoutesCommand = cli.Command{
 		},
 		cli.Int64Flag{
 			Name: "fee_limit",
-			Usage: "maximum total fees for the payment in satoshis",
+			Usage: "maximum fee allowed in satoshis when sending" +
+				"the payment",
 		},
 		cli.Int64Flag{
 			Name: "fee_limit_percent",
-			Usage: "maximum total fees as a percentage of amt",
+			Usage: "percentage of the payment's amount used as the" +
+				"maximum fee allowed when sending the payment",
 		},
 		cli.Int64Flag{
 			Name:  "num_max_routes",
@@ -2588,7 +2595,6 @@ func queryRoutes(ctx *cli.Context) error {
 		dest string
 		amt  int64
 		err  error
-		feeLimit int64
 	)
 
 	args := ctx.Args()
@@ -2615,11 +2621,15 @@ func queryRoutes(ctx *cli.Context) error {
 		return fmt.Errorf("amt argument missing")
 	}
 
-	feeLimit = calculateFeeLimit(ctx, amt)
+	feeLimit, err := retrieveFeeLimit(ctx)
+	if err != nil {
+		return err
+	}
 
 	req := &lnrpc.QueryRoutesRequest{
 		PubKey:         dest,
 		Amt:            amt,
+		FeeLimit:       feeLimit,
 		NumRoutes:      int32(ctx.Int("num_max_routes")),
 		FinalCltvDelta: int32(ctx.Int("final_cltv_delta")),
 	}