lnd: extract neutrino initialization to new function

chainregistry.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
@@ -16,6 +17,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/chain"
 	"github.com/btcsuite/btcwallet/wallet"
+	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/lightninglabs/neutrino"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainntnfs/bitcoindnotify"
@@ -663,3 +665,79 @@ func (c *chainRegistry) NumActiveChains() uint32 {
 
 	return uint32(len(c.activeChains))
 }
+
+// initNeutrinoBackend inits a new instance of the neutrino light client
+// backend given a target chain directory to store the chain state.
+func initNeutrinoBackend(chainDir string) (*neutrino.ChainService, func(), error) {
+	// First we'll open the database file for neutrino, creating the
+	// database if needed. We append the normalized network name here to
+	// match the behavior of btcwallet.
+	dbPath := filepath.Join(
+		chainDir,
+		normalizeNetwork(activeNetParams.Name),
+	)
+
+	// Ensure that the neutrino db path exists.
+	if err := os.MkdirAll(dbPath, 0700); err != nil {
+		return nil, nil, err
+	}
+
+	dbName := filepath.Join(dbPath, "neutrino.db")
+	db, err := walletdb.Create("bdb", dbName)
+	if err != nil {
+		return nil, nil, fmt.Errorf("unable to create neutrino "+
+			"database: %v", err)
+	}
+
+	// With the database open, we can now create an instance of the
+	// neutrino light client. We pass in relevant configuration parameters
+	// required.
+	config := neutrino.Config{
+		DataDir:      dbPath,
+		Database:     db,
+		ChainParams:  *activeNetParams.Params,
+		AddPeers:     cfg.NeutrinoMode.AddPeers,
+		ConnectPeers: cfg.NeutrinoMode.ConnectPeers,
+		Dialer: func(addr net.Addr) (net.Conn, error) {
+			return cfg.net.Dial(addr.Network(), addr.String())
+		},
+		NameResolver: func(host string) ([]net.IP, error) {
+			addrs, err := cfg.net.LookupHost(host)
+			if err != nil {
+				return nil, err
+			}
+
+			ips := make([]net.IP, 0, len(addrs))
+			for _, strIP := range addrs {
+				ip := net.ParseIP(strIP)
+				if ip == nil {
+					continue
+				}
+
+				ips = append(ips, ip)
+			}
+
+			return ips, nil
+		},
+	}
+
+	neutrino.MaxPeers = 8
+	neutrino.BanDuration = 5 * time.Second
+
+	neutrinoCS, err := neutrino.NewChainService(config)
+	if err != nil {
+		return nil, nil, fmt.Errorf("unable to create neutrino light "+
+			"client: %v", err)
+	}
+
+	cleanUp := func() {
+		db.Close()
+		neutrinoCS.Stop()
+	}
+	if err := neutrinoCS.Start(); err != nil {
+		cleanUp()
+		return nil, nil, err
+	}
+
+	return neutrinoCS, cleanUp, nil
+}

lnd.go

@@ -35,7 +35,6 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcwallet/wallet"
-	"github.com/btcsuite/btcwallet/walletdb"
 	proxy "github.com/grpc-ecosystem/grpc-gateway/runtime"
 	flags "github.com/jessevdk/go-flags"
 	"github.com/lightninglabs/neutrino"
@@ -198,79 +197,23 @@ func lndMain() error {
 	}
 	proxyOpts := []grpc.DialOption{grpc.WithTransportCredentials(cCreds)}
 
-	// Before starting the wallet, we'll create and start our Neutrino light
-	// client instance, if enabled, in order to allow it to sync while the
-	// rest of the daemon continues startup.
+	// Before starting the wallet, we'll create and start our Neutrino
+	// light client instance, if enabled, in order to allow it to sync
+	// while the rest of the daemon continues startup.
 	mainChain := cfg.Bitcoin
 	if registeredChains.PrimaryChain() == litecoinChain {
 		mainChain = cfg.Litecoin
 	}
 	var neutrinoCS *neutrino.ChainService
 	if mainChain.Node == "neutrino" {
-		// First we'll open the database file for neutrino, creating
-		// the database if needed. We append the normalized network name
-		// here to match the behavior of btcwallet.
-		dbPath := filepath.Join(
+		neutrinoBackend, neutrinoCleanUp, err := initNeutrinoBackend(
 			mainChain.ChainDir,
-			normalizeNetwork(activeNetParams.Name),
 		)
-
-		// Ensure that the neutrino db path exists.
-		if err := os.MkdirAll(dbPath, 0700); err != nil {
-			return err
-		}
-
-		dbName := filepath.Join(dbPath, "neutrino.db")
-		db, err := walletdb.Create("bdb", dbName)
+		defer neutrinoCleanUp()
 		if err != nil {
-			return fmt.Errorf("unable to create neutrino "+
-				"database: %v", err)
-		}
-		defer db.Close()
-
-		// With the database open, we can now create an instance of the
-		// neutrino light client. We pass in relevant configuration
-		// parameters required.
-		config := neutrino.Config{
-			DataDir:      dbPath,
-			Database:     db,
-			ChainParams:  *activeNetParams.Params,
-			AddPeers:     cfg.NeutrinoMode.AddPeers,
-			ConnectPeers: cfg.NeutrinoMode.ConnectPeers,
-			Dialer: func(addr net.Addr) (net.Conn, error) {
-				return cfg.net.Dial(addr.Network(), addr.String())
-			},
-			NameResolver: func(host string) ([]net.IP, error) {
-				addrs, err := cfg.net.LookupHost(host)
-				if err != nil {
-					return nil, err
-				}
-
-				ips := make([]net.IP, 0, len(addrs))
-				for _, strIP := range addrs {
-					ip := net.ParseIP(strIP)
-					if ip == nil {
-						continue
-					}
-
-					ips = append(ips, ip)
-				}
-
-				return ips, nil
-			},
-		}
-
-		neutrino.MaxPeers = 8
-		neutrino.BanDuration = 5 * time.Second
-
-		neutrinoCS, err = neutrino.NewChainService(config)
-		if err != nil {
-			return fmt.Errorf("unable to create neutrino light "+
-				"client: %v", err)
+			return err
 		}
-
-		neutrinoCS.Start()
-		defer neutrinoCS.Stop()
+		neutrinoCS = neutrinoBackend
 	}
 
 	var (