Merge pull request #129 from halseth/loop-out-quote-deadline

Loop out quote with fast option

Author: halseth

client.go

@@ -369,7 +369,9 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 		return nil, ErrSwapAmountTooHigh
 	}
 
-	quote, err := s.Server.GetLoopOutQuote(ctx, request.Amount)
+	quote, err := s.Server.GetLoopOutQuote(
+		ctx, request.Amount, request.SwapPublicationDeadline,
+	)
 	if err != nil {
 		return nil, err
 	}

cmd/loop/loopout.go

@@ -93,18 +93,26 @@ func loopOut(ctx *cli.Context) error {
 	}
 	defer cleanup()
 
+	// Set our maximum swap wait time. If a fast swap is requested we set
+	// it to now, otherwise to 30 minutes in the future.
+	fast := ctx.Bool("fast")
+	swapDeadline := time.Now()
+	if !fast {
+		swapDeadline = time.Now().Add(defaultSwapWaitTime)
+	}
+
 	sweepConfTarget := int32(ctx.Uint64("conf_target"))
 	quoteReq := &looprpc.QuoteRequest{
-		Amt:        int64(amt),
-		ConfTarget: sweepConfTarget,
+		Amt:                     int64(amt),
+		ConfTarget:              sweepConfTarget,
+		SwapPublicationDeadline: uint64(swapDeadline.Unix()),
 	}
 	quote, err := client.LoopOutQuote(context.Background(), quoteReq)
 	if err != nil {
 		return err
 	}
 
 	// Show a warning if a slow swap was requested.
-	fast := ctx.Bool("fast")
 	warning := ""
 	if fast {
 		warning = "Fast swap requested."
@@ -125,13 +133,6 @@ func loopOut(ctx *cli.Context) error {
 		unchargeChannel = ctx.Uint64("channel")
 	}
 
-	// Set our maximum swap wait time. If a fast swap is requested we set
-	// it to now, otherwise to 30 minutes in the future.
-	swapDeadline := time.Now()
-	if !fast {
-		swapDeadline = time.Now().Add(defaultSwapWaitTime)
-	}
-
 	resp, err := client.LoopOut(context.Background(), &looprpc.LoopOutRequest{
 		Amt:                     int64(amt),
 		Dest:                    destAddr,

cmd/loop/quote.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"time"
 
 	"github.com/lightninglabs/loop/looprpc"
 	"github.com/urfave/cli"
@@ -20,6 +21,16 @@ var quoteCommand = cli.Command{
 				"should be swept within in a Loop Out",
 			Value: 6,
 		},
+		cli.BoolFlag{
+			Name: "fast",
+			Usage: "Indicate you want to swap immediately, " +
+				"paying potentially a higher fee. If not " +
+				"set the swap server might choose to wait up " +
+				"to 30 minutes before publishing the swap " +
+				"HTLC on-chain, to save on chain fees. Not " +
+				"setting this flag might result in a lower " +
+				"swap fee.",
+		},
 	},
 	Action: quote,
 }
@@ -43,10 +54,17 @@ func quote(ctx *cli.Context) error {
 	}
 	defer cleanup()
 
+	fast := ctx.Bool("fast")
+	swapDeadline := time.Now()
+	if !fast {
+		swapDeadline = time.Now().Add(defaultSwapWaitTime)
+	}
+
 	ctxb := context.Background()
 	resp, err := client.LoopOutQuote(ctxb, &looprpc.QuoteRequest{
-		Amt:        int64(amt),
-		ConfTarget: int32(ctx.Uint64("conf_target")),
+		Amt:                     int64(amt),
+		ConfTarget:              int32(ctx.Uint64("conf_target")),
+		SwapPublicationDeadline: uint64(swapDeadline.Unix()),
 	})
 	if err != nil {
 		return err

interface.go

@@ -99,6 +99,10 @@ type LoopOutQuoteRequest struct {
 	// client sweep tx.
 	SweepConfTarget int32
 
+	// SwapPublicationDeadline can be set by the client to allow the server
+	// delaying publication of the swap HTLC to save on chain fees.
+	SwapPublicationDeadline time.Time
+
 	// TODO: Add argument to specify confirmation target for server
 	// publishing htlc. This may influence the swap fee quote, because the
 	// server needs to pay more for faster confirmations.

loopd/swapclient_server.go

@@ -266,6 +266,9 @@ func (s *swapClientServer) LoopOutQuote(ctx context.Context,
 	quote, err := s.impl.LoopOutQuote(ctx, &loop.LoopOutQuoteRequest{
 		Amount:          btcutil.Amount(req.Amt),
 		SweepConfTarget: confTarget,
+		SwapPublicationDeadline: time.Unix(
+			int64(req.SwapPublicationDeadline), 0,
+		),
 	})
 	if err != nil {
 		return nil, err

looprpc/client.pb.go

@@ -356,6 +356,15 @@ message QuoteRequest {
     actor.
     */
     bool external_htlc = 3;
+
+    /**
+    The latest time (in unix seconds) we allow the server to wait before
+    publishing the HTLC on chain. Setting this to a larger value will give the
+    server the opportunity to batch multiple swaps together, and wait for
+    low-fee periods before publishing the HTLC, potentially resulting in a
+    lower total swap fee.
+    */
+    uint64 swap_publication_deadline = 4;
 }
 
 message QuoteResponse {

looprpc/client.proto

@@ -78,6 +78,14 @@
             "required": false,
             "type": "boolean",
             "format": "boolean"
+          },
+          {
+            "name": "swap_publication_deadline",
+            "description": "*\nThe latest time (in unix seconds) we allow the server to wait before\npublishing the HTLC on chain. Setting this to a larger value will give the\nserver the opportunity to batch multiple swaps together, and wait for\nlow-fee periods before publishing the HTLC, potentially resulting in a\nlower total swap fee.",
+            "in": "query",
+            "required": false,
+            "type": "string",
+            "format": "uint64"
           }
         ],
         "tags": [
@@ -165,6 +173,14 @@
             "required": false,
             "type": "boolean",
             "format": "boolean"
+          },
+          {
+            "name": "swap_publication_deadline",
+            "description": "*\nThe latest time (in unix seconds) we allow the server to wait before\npublishing the HTLC on chain. Setting this to a larger value will give the\nserver the opportunity to batch multiple swaps together, and wait for\nlow-fee periods before publishing the HTLC, potentially resulting in a\nlower total swap fee.",
+            "in": "query",
+            "required": false,
+            "type": "string",
+            "format": "uint64"
           }
         ],
         "tags": [

looprpc/client.swagger.json

@@ -42,6 +42,9 @@ message ServerLoopOutResponse {
 message ServerLoopOutQuoteRequest {
     /// The swap amount. If zero, a quote for a maximum amt swap will be given.
     uint64 amt = 1;
+
+    /// The unix time in seconds we want the on-chain swap to be published by.
+    int64 swap_publication_deadline = 2;
 }
 
 message ServerLoopOutQuote {