From d9c4ada99102c7a42fa8637859217ec857b5afa6 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Thu, 15 Jun 2023 08:19:49 +0200
Subject: [PATCH] multi: add wtclient config defaults to lnd config

In this commit, a `DefaultWtClientCfg` function is added which
populates some default values for the `WtClient` struct. This is then
used to populate the wtclient defaults in the main LND config struct.
---
 config.go         |  1 +
 lncfg/wtclient.go | 40 +++++++++++++++++++++++++++++++++++++++-
 server.go         | 36 +++++++++++-------------------------
 3 files changed, 51 insertions(+), 26 deletions(-)

diff --git a/config.go b/config.go
index 5018994a7..d3d28a2b3 100644
--- a/config.go
+++ b/config.go
@@ -713,6 +713,7 @@ func DefaultConfig() Config {
 			ServerPingTimeout: defaultGrpcServerPingTimeout,
 			ClientPingMinWait: defaultGrpcClientPingMinWait,
 		},
+		WtClient: lncfg.DefaultWtClientCfg(),
 	}
 }
 
diff --git a/lncfg/wtclient.go b/lncfg/wtclient.go
index 7a6959adf..aab71faea 100644
--- a/lncfg/wtclient.go
+++ b/lncfg/wtclient.go
@@ -1,6 +1,11 @@
 package lncfg
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/watchtower/wtclient"
+	"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
+)
 
 // WtClient holds the configuration options for the daemon's watchtower client.
 //
@@ -32,6 +37,23 @@ type WtClient struct {
 	MaxUpdates uint16 `long:"max-updates" description:"The maximum number of updates to be backed up in a single session."`
 }
 
+// DefaultWtClientCfg returns the WtClient config struct with some default
+// values populated.
+func DefaultWtClientCfg() *WtClient {
+	// The sweep fee rate used internally by the tower client is in sats/kw
+	// but the config exposed to the user is in sats/byte, so we convert the
+	// default here before exposing it to the user.
+	sweepSatsPerKvB := wtpolicy.DefaultSweepFeeRate.FeePerKVByte()
+	sweepFeeRate := uint64(sweepSatsPerKvB / 1000)
+
+	return &WtClient{
+		SweepFeeRate:       sweepFeeRate,
+		SessionCloseRange:  wtclient.DefaultSessionCloseRange,
+		MaxTasksInMemQueue: wtclient.DefaultMaxTasksInMemQueue,
+		MaxUpdates:         wtpolicy.DefaultMaxUpdates,
+	}
+}
+
 // Validate ensures the user has provided a valid configuration.
 //
 // NOTE: Part of the Validator interface.
@@ -45,6 +67,22 @@ func (c *WtClient) Validate() error {
 			"`lncli wtclient -h` for more information")
 	}
 
+	if c.SweepFeeRate == 0 {
+		return fmt.Errorf("sweep-fee-rate must be non-zero")
+	}
+
+	if c.MaxUpdates == 0 {
+		return fmt.Errorf("max-updates must be non-zero")
+	}
+
+	if c.MaxTasksInMemQueue == 0 {
+		return fmt.Errorf("max-tasks-in-mem-queue must be non-zero")
+	}
+
+	if c.SessionCloseRange == 0 {
+		return fmt.Errorf("session-close-range must be non-zero")
+	}
+
 	return nil
 }
 
diff --git a/server.go b/server.go
index 35e375452..4719691e9 100644
--- a/server.go
+++ b/server.go
@@ -1497,29 +1497,15 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 
 	if cfg.WtClient.Active {
 		policy := wtpolicy.DefaultPolicy()
+		policy.MaxUpdates = cfg.WtClient.MaxUpdates
 
-		if cfg.WtClient.SweepFeeRate != 0 {
-			// We expose the sweep fee rate in sat/vbyte, but the
-			// tower protocol operations on sat/kw.
-			sweepRateSatPerVByte := chainfee.SatPerKVByte(
-				1000 * cfg.WtClient.SweepFeeRate,
-			)
-			policy.SweepFeeRate = sweepRateSatPerVByte.FeePerKWeight()
-		}
+		// We expose the sweep fee rate in sat/vbyte, but the tower
+		// protocol operations on sat/kw.
+		sweepRateSatPerVByte := chainfee.SatPerKVByte(
+			1000 * cfg.WtClient.SweepFeeRate,
+		)
 
-		if cfg.WtClient.MaxUpdates != 0 {
-			policy.MaxUpdates = cfg.WtClient.MaxUpdates
-		}
-
-		sessionCloseRange := uint32(wtclient.DefaultSessionCloseRange)
-		if cfg.WtClient.SessionCloseRange != 0 {
-			sessionCloseRange = cfg.WtClient.SessionCloseRange
-		}
-
-		maxTasksInMemQueue := uint64(wtclient.DefaultMaxTasksInMemQueue)
-		if cfg.WtClient.MaxTasksInMemQueue != 0 {
-			maxTasksInMemQueue = cfg.WtClient.MaxTasksInMemQueue
-		}
+		policy.SweepFeeRate = sweepRateSatPerVByte.FeePerKWeight()
 
 		if err := policy.Validate(); err != nil {
 			return nil, err
@@ -1565,7 +1551,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		s.towerClient, err = wtclient.New(&wtclient.Config{
 			FetchClosedChannel:     fetchClosedChannel,
 			BuildBreachRetribution: buildBreachRetribution,
-			SessionCloseRange:      sessionCloseRange,
+			SessionCloseRange:      cfg.WtClient.SessionCloseRange,
 			ChainNotifier:          s.cc.ChainNotifier,
 			SubscribeChannelEvents: func() (subscribe.Subscription,
 				error) {
@@ -1584,7 +1570,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 			MinBackoff:         10 * time.Second,
 			MaxBackoff:         5 * time.Minute,
 			ForceQuitDelay:     wtclient.DefaultForceQuitDelay,
-			MaxTasksInMemQueue: maxTasksInMemQueue,
+			MaxTasksInMemQueue: cfg.WtClient.MaxTasksInMemQueue,
 		})
 		if err != nil {
 			return nil, err
@@ -1599,7 +1585,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		s.anchorTowerClient, err = wtclient.New(&wtclient.Config{
 			FetchClosedChannel:     fetchClosedChannel,
 			BuildBreachRetribution: buildBreachRetribution,
-			SessionCloseRange:      sessionCloseRange,
+			SessionCloseRange:      cfg.WtClient.SessionCloseRange,
 			ChainNotifier:          s.cc.ChainNotifier,
 			SubscribeChannelEvents: func() (subscribe.Subscription,
 				error) {
@@ -1618,7 +1604,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 			MinBackoff:         10 * time.Second,
 			MaxBackoff:         5 * time.Minute,
 			ForceQuitDelay:     wtclient.DefaultForceQuitDelay,
-			MaxTasksInMemQueue: maxTasksInMemQueue,
+			MaxTasksInMemQueue: cfg.WtClient.MaxTasksInMemQueue,
 		})
 		if err != nil {
 			return nil, err