Merge pull request #16 from lightningnetwork/chainnotifier-interface

Refactor the chainntfs package to accommodate future ChainNotifier implementations

chainntfs/chainntfs_test.go

@@ -1 +0,0 @@
-package chainntnfs

chainntnfs/btcdnotify/btcd.go

@@ -7,13 +7,20 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/lightningnetwork/lnd/chainntfs"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/roasbeef/btcd/btcjson"
 	"github.com/roasbeef/btcd/wire"
 	"github.com/roasbeef/btcrpcclient"
 	"github.com/roasbeef/btcutil"
 )
 
+const (
+
+	// notifierType uniquely identifies this concrete implementation of the
+	// ChainNotifier interface.
+	notifierType = "btcd"
+)
+
 // BtcdNotifier implements the ChainNotifier interface using btcd's websockets
 // notifications. Multiple concurrent clients are supported. All notifications
 // are achieved via non-blocking sends on client channels.
@@ -42,10 +49,10 @@ type BtcdNotifier struct {
 // Ensure BtcdNotifier implements the ChainNotifier interface at compile time.
 var _ chainntnfs.ChainNotifier = (*BtcdNotifier)(nil)
 
-// NewBtcdNotifier returns a new BtcdNotifier instance. This function assumes
-// the btcd node detailed in the passed configuration is already running, and
+// New returns a new BtcdNotifier instance. This function assumes the btcd node
+// detailed in the passed configuration is already running, and
 // willing to accept new websockets clients.
-func NewBtcdNotifier(config *btcrpcclient.ConnConfig) (*BtcdNotifier, error) {
+func New(config *btcrpcclient.ConnConfig) (*BtcdNotifier, error) {
 	notifier := &BtcdNotifier{
 		notificationRegistry: make(chan interface{}),
 
@@ -66,8 +73,8 @@ func NewBtcdNotifier(config *btcrpcclient.ConnConfig) (*BtcdNotifier, error) {
 		OnRedeemingTx:       notifier.onRedeemingTx,
 	}
 
-	// Disable connecting to btcd within the btcrpcclient.New method. We defer
-	// establishing the connection to our .Start() method.
+	// Disable connecting to btcd within the btcrpcclient.New method. We
+	// defer establishing the connection to our .Start() method.
 	config.DisableConnectOnNew = true
 	config.DisableAutoReconnect = false
 	chainConn, err := btcrpcclient.New(config, ntfnCallbacks)

chainntnfs/btcdnotify/confheap.go

@@ -1,17 +1,21 @@
 package btcdnotify
 
-// confEntry...
+// confEntry represents an entry in the min-confirmation heap. .
 type confEntry struct {
 	*confirmationsNotification
 
 	triggerHeight uint32
 }
 
-// confirmationHeap...
+// confirmationHeap is a list of confEntries sorted according to nearest
+// "confirmation" height.Each entry within the min-confirmation heap is sorted
+// according to the smallest dleta from the current blockheight to the
+// triggerHeight of the next entry confirmationHeap
 type confirmationHeap struct {
 	items []*confEntry
 }
 
+// newConfirmationHeap returns a new confirmationHeap with zero items.
 func newConfirmationHeap() *confirmationHeap {
 	var confItems []*confEntry
 	return &confirmationHeap{confItems}

chainntnfs/btcdnotify/driver.go

@@ -0,0 +1,40 @@
+package btcdnotify
+
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/roasbeef/btcrpcclient"
+)
+
+// createNewNotifier creates a new instance of the ChainNotifier interface
+// implemented by BtcdNotifier.
+func createNewNotifier(args ...interface{}) (chainntnfs.ChainNotifier, error) {
+	if len(args) != 1 {
+		return nil, fmt.Errorf("incorrect number of arguments to .New(...), "+
+			"expected 1, instead passed %v", len(args))
+	}
+
+	config, ok := args[0].(*btcrpcclient.ConnConfig)
+	if !ok {
+		return nil, fmt.Errorf("first argument to btcdnotifier.New is " +
+			"incorrect, expected a *btcrpcclient.ConnConfig")
+	}
+
+	return New(config)
+}
+
+// init registers a driver for the BtcdNotifier concrete implementation of the
+// chainntnfs.ChainNotifier interface.
+func init() {
+	// Register the driver.
+	notifier := &chainntnfs.NotifierDriver{
+		NotifierType: notifierType,
+		New:          createNewNotifier,
+	}
+
+	if err := chainntnfs.RegisterNotifier(notifier); err != nil {
+		panic(fmt.Sprintf("failed to register notifier driver '%s': %v",
+			notifierType, err))
+	}
+}

chainntnfs/interface.go

@@ -1,6 +1,11 @@
 package chainntnfs
 
-import "github.com/roasbeef/btcd/wire"
+import (
+	"fmt"
+	"sync"
+
+	"github.com/roasbeef/btcd/wire"
+)
 
 // ChainNotifier represents a trusted source to receive notifications concerning
 // targeted events on the Bitcoin blockchain. The interface specification is
@@ -104,3 +109,74 @@ type BlockEpoch struct {
 type BlockEpochEvent struct {
 	Epochs chan *BlockEpoch // MUST be buffered.
 }
+
+// NotifierDriver represents a "driver" for a particular interface. A driver is
+// indentified by a globally unique string identifier along with a 'New()'
+// method which is responsible for initializing a particular ChainNotifier
+// concrete implementation.
+type NotifierDriver struct {
+	// NotifierType is a string which uniquely identifes the ChainNotifier
+	// that this driver, drives.
+	NotifierType string
+
+	// New creates a new instance of a concrete ChainNotifier
+	// implementation given a variadic set up arguments. The function takes
+	// a varidaic number of interface paramters in order to provide
+	// initialization flexibility, thereby accomodating several potential
+	// ChainNotifier implementations.
+	New func(args ...interface{}) (ChainNotifier, error)
+}
+
+var (
+	notifiers   = make(map[string]*NotifierDriver)
+	registerMtx sync.Mutex
+)
+
+// RegisteredNotifiers returns a slice of all currently registered notifiers.
+//
+// NOTE: This function is safe for concurrent access.
+func RegisteredNotifiers() []*NotifierDriver {
+	registerMtx.Lock()
+	defer registerMtx.Unlock()
+
+	drivers := make([]*NotifierDriver, 0, len(notifiers))
+	for _, driver := range notifiers {
+		drivers = append(drivers, driver)
+	}
+
+	return drivers
+}
+
+// RegisterNotifier registers a NotifierDriver which is capable of driving a
+// concrete ChainNotifier interface. In the case that this driver has already
+// been registered, an error is returned.
+//
+// NOTE: This function is safe for concurrent access.
+func RegisterNotifier(driver *NotifierDriver) error {
+	registerMtx.Lock()
+	defer registerMtx.Unlock()
+
+	if _, ok := notifiers[driver.NotifierType]; ok {
+		return fmt.Errorf("notifier already registered")
+	}
+
+	notifiers[driver.NotifierType] = driver
+
+	return nil
+}
+
+// SupportedNotifiers returns a slice of strings that represent the database
+// drivers that have been registered and are therefore supported.
+//
+// NOTE: This function is safe for concurrent access.
+func SupportedNotifiers() []string {
+	registerMtx.Lock()
+	defer registerMtx.Unlock()
+
+	supportedNotifiers := make([]string, 0, len(notifiers))
+	for driverName := range notifiers {
+		supportedNotifiers = append(supportedNotifiers, driverName)
+	}
+
+	return supportedNotifiers
+}

chainntnfs/interface_test.go

@@ -1,11 +1,13 @@
-package btcdnotify
+package chainntnfs_test
 
 import (
 	"bytes"
 	"testing"
 	"time"
 
-	"github.com/lightningnetwork/lnd/chainntfs"
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	_ "github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
+
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/chaincfg"
 	"github.com/roasbeef/btcd/rpctest"
@@ -181,7 +183,7 @@ func testSpendNotification(miner *rpctest.Harness,
 	notifier chainntnfs.ChainNotifier, t *testing.T) {
 
 	// We'd like to test the spend notifiations for all
-	// chainntnfs.ChainNotifier concrete implemenations.
+	// ChainNotifier concrete implemenations.
 	//
 	// To do so, we first create a new output to our test target
 	// address.
@@ -286,15 +288,22 @@ var ntfnTests = []func(node *rpctest.Harness, notifier chainntnfs.ChainNotifier,
 	testSpendNotification,
 }
 
-// TODO(roasbeef): make test generic across all interfaces?
-//  * indeed!
-//  * requires interface implementation registration
-func TestBtcdNotifier(t *testing.T) {
-
+// TestInterfaces tests all registered interfaces with a unified set of tests
+// which excersie each of the required methods found within the ChainNotifier
+// interface.
+//
+// NOTE: In the future, when additional implementations of the ChainNotifier
+// interface have been implemented, in order to ensure the new concrete
+// implementation is automatically tested, two steps must be undertaken. First,
+// one needs add a "non-captured" (_) import from the new sub-package. This
+// import should trigger an init() method within the package which registeres
+// the interface. Second, an additional case in the switch within the main loop
+// below needs to be added which properly initializes the interface.
+func TestInterfaces(t *testing.T) {
 	// Initialize the harness around a btcd node which will serve as our
-	// dedicated miner to generate blocks, cause re-orgs, etc. We'll set
-	// up this node with a chain length of 125, so we have plentyyy of BTC
-	// to play around with.
+	// dedicated miner to generate blocks, cause re-orgs, etc. We'll set up
+	// this node with a chain length of 125, so we have plentyyy of BTC to
+	// play around with.
 	miner, err := rpctest.New(netParams, nil, nil)
 	if err != nil {
 		t.Fatalf("unable to create mining node: %v", err)
@@ -304,17 +313,30 @@ func TestBtcdNotifier(t *testing.T) {
 		t.Fatalf("unable to set up mining node: %v", err)
 	}
 
-	nodeConfig := miner.RPCConfig()
-	notifier, err := NewBtcdNotifier(&nodeConfig)
-	if err != nil {
-		t.Fatalf("unable to create notifier: %v", err)
-	}
-	if err := notifier.Start(); err != nil {
-		t.Fatalf("unable to start notifier: %v", err)
-	}
-	defer notifier.Stop()
+	rpcConfig := miner.RPCConfig()
 
-	for _, ntfnTest := range ntfnTests {
-		ntfnTest(miner, notifier, t)
+	var notifier chainntnfs.ChainNotifier
+	for _, notifierDriver := range chainntnfs.RegisteredNotifiers() {
+		notifierType := notifierDriver.NotifierType
+
+		switch notifierType {
+		case "btcd":
+			notifier, err = notifierDriver.New(&rpcConfig)
+			if err != nil {
+				t.Fatalf("unable to create %v notifier: %v",
+					notifierType, err)
+			}
+		}
+
+		if err := notifier.Start(); err != nil {
+			t.Fatalf("unable to start notifier %v: %v",
+				notifierType, err)
+		}
+
+		for _, ntfnTest := range ntfnTests {
+			ntfnTest(miner, notifier, t)
+		}
+
+		notifier.Stop()
 	}
 }

htlcswitch.go

@@ -89,6 +89,7 @@ func newHtlcSwitch() *htlcSwitch {
 		linkControl:      make(chan interface{}),
 		htlcPlex:         make(chan *htlcPacket, htlcQueueSize),
 		outgoingPayments: make(chan *htlcPacket, htlcQueueSize),
+		quit:             make(chan struct{}),
 	}
 }
 

lnd.go

@@ -14,9 +14,11 @@ import (
 
 	"google.golang.org/grpc"
 
+	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/roasbeef/btcrpcclient"
 )
 
 var (
@@ -94,9 +96,29 @@ func lndMain() error {
 		return err
 	}
 
-	// Create, and start the lnwallet, which handles the core payment channel
-	// logic, and exposes control via proxy state machines.
-	config := &lnwallet.Config{
+	btcdHost := fmt.Sprintf("%v:%v", loadedConfig.RPCHost, activeNetParams.rpcPort)
+	btcdUser := loadedConfig.RPCUser
+	btcdPass := loadedConfig.RPCPass
+
+	// TODO(roasbeef): parse config here and select chosen notifier instead
+	rpcConfig := &btcrpcclient.ConnConfig{
+		Host:                 btcdHost,
+		Endpoint:             "ws",
+		User:                 btcdUser,
+		Pass:                 btcdPass,
+		Certificates:         rpcCert,
+		DisableTLS:           false,
+		DisableConnectOnNew:  true,
+		DisableAutoReconnect: false,
+	}
+	notifier, err := btcdnotify.New(rpcConfig)
+	if err != nil {
+		return err
+	}
+
+	// Create, and start the lnwallet, which handles the core payment
+	// channel logic, and exposes control via proxy state machines.
+	walletConfig := &lnwallet.Config{
 		PrivatePass: []byte("hello"),
 		DataDir:     filepath.Join(loadedConfig.DataDir, "lnwallet"),
 		RpcHost:     fmt.Sprintf("%v:%v", rpcIP[0], activeNetParams.rpcPort),
@@ -105,7 +127,7 @@ func lndMain() error {
 		CACert:      rpcCert,
 		NetParams:   activeNetParams.Params,
 	}
-	wallet, err := lnwallet.NewLightningWallet(config, chanDB)
+	wallet, err := lnwallet.NewLightningWallet(walletConfig, chanDB, notifier)
 	if err != nil {
 		fmt.Printf("unable to create wallet: %v\n", err)
 		return err
@@ -124,12 +146,15 @@ func lndMain() error {
 	defaultListenAddrs := []string{
 		net.JoinHostPort("", strconv.Itoa(loadedConfig.PeerPort)),
 	}
-	server, err := newServer(defaultListenAddrs, wallet, chanDB)
+	server, err := newServer(defaultListenAddrs, notifier, wallet, chanDB)
 	if err != nil {
 		srvrLog.Errorf("unable to create server: %v\n", err)
 		return err
 	}
-	server.Start()
+	if err := server.Start(); err != nil {
+		srvrLog.Errorf("unable to create to start: %v\n", err)
+		return err
+	}
 
 	addInterruptHandler(func() {
 		ltndLog.Infof("Gracefully shutting down the server...")

lnwallet/channel.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/btcsuite/fastsha256"
 	"github.com/davecgh/go-spew/spew"
-	"github.com/lightningnetwork/lnd/chainntfs"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwire"
 

lnwallet/interface.go

@@ -13,9 +13,9 @@ import (
 // such as: uspv, btcwallet, Bitcoin Core, Electrum, etc. This interface then
 // serves as a "base wallet", with Lightning Network awareness taking place at
 // a "higher" level of abstraction. Essentially, an overlay wallet.
-// Implementors of this interface must closely adhere to the documented behavior
-// of all interface methods in order to ensure identical behavior accross all
-// concrete implementations.
+// Implementors of this interface must closely adhere to the documented
+// behavior of all interface methods in order to ensure identical behavior
+// across all concrete implementations.
 type WalletController interface {
 	// ConfirmedBalance returns the sum of all the wallet's unspent outputs
 	// that have at least confs confirmations. If confs is set to zero,

lnwallet/wallet.go

@@ -9,8 +9,7 @@ import (
 	"sync/atomic"
 
 	"github.com/davecgh/go-spew/spew"
-	"github.com/lightningnetwork/lnd/chainntfs"
-	"github.com/lightningnetwork/lnd/chainntfs/btcdnotify"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/elkrem"
 	"github.com/roasbeef/btcd/btcjson"
@@ -18,7 +17,6 @@ import (
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/txscript"
 	"github.com/roasbeef/btcd/wire"
-	"github.com/roasbeef/btcrpcclient"
 	"github.com/roasbeef/btcutil"
 	"github.com/roasbeef/btcutil/coinset"
 	"github.com/roasbeef/btcutil/txsort"
@@ -234,8 +232,7 @@ type LightningWallet struct {
 	// Used by in order to obtain notifications about funding transaction
 	// reaching a specified confirmation depth, and to catch
 	// counterparty's broadcasting revoked commitment states.
-	// TODO(roasbeef): needs to be stripped out from wallet
-	ChainNotifier chainntnfs.ChainNotifier
+	chainNotifier chainntnfs.ChainNotifier
 
 	// The core wallet, all non Lightning Network specific interaction is
 	// proxied to the internal wallet.
@@ -279,7 +276,12 @@ type LightningWallet struct {
 // NewLightningWallet creates/opens and initializes a LightningWallet instance.
 // If the wallet has never been created (according to the passed dataDir), first-time
 // setup is executed.
-func NewLightningWallet(config *Config, cdb *channeldb.DB) (*LightningWallet, error) {
+//
+// NOTE: The passed channeldb, and ChainNotifier should already be fully
+// initialized/started before being passed as a function arugment.
+func NewLightningWallet(config *Config, cdb *channeldb.DB,
+	notifier chainntnfs.ChainNotifier) (*LightningWallet, error) {
+
 	// Ensure the wallet exists or create it when the create flag is set.
 	netDir := networkDir(config.DataDir, config.NetParams)
 
@@ -344,26 +346,8 @@ func NewLightningWallet(config *Config, cdb *channeldb.DB) (*LightningWallet, er
 		return nil, err
 	}
 
-	// Using the same authentication info, create a config for a second
-	// rpcclient which will be used by the current default chain
-	// notifier implemenation.
-	rpcConfig := &btcrpcclient.ConnConfig{
-		Host:                 config.RpcHost,
-		Endpoint:             "ws",
-		User:                 config.RpcUser,
-		Pass:                 config.RpcPass,
-		Certificates:         config.CACert,
-		DisableTLS:           false,
-		DisableConnectOnNew:  true,
-		DisableAutoReconnect: false,
-	}
-	chainNotifier, err := btcdnotify.NewBtcdNotifier(rpcConfig)
-	if err != nil {
-		return nil, err
-	}
-
 	return &LightningWallet{
-		ChainNotifier: chainNotifier,
+		chainNotifier: notifier,
 		rpc:           rpcc,
 		Wallet:        wallet,
 		channelDB:     cdb,
@@ -393,17 +377,8 @@ func (l *LightningWallet) Startup() error {
 	}
 	l.Start()
 
-	// Start the notification server. This is used so channel managment
-	// goroutines can be notified when a funding transaction reaches a
-	// sufficient number of confirmations, or when the input for the funding
-	// transaction is spent in an attempt at an uncooperative close by the
-	// counter party.
-	if err := l.ChainNotifier.Start(); err != nil {
-		return err
-	}
-
-	// Pass the rpc client into the wallet so it can sync up to the current
-	// main chain.
+	// Pass the rpc client into the wallet so it can sync up to the
+	// current main chain.
 	l.SynchronizeRPC(l.rpc)
 
 	l.wg.Add(1)
@@ -426,8 +401,6 @@ func (l *LightningWallet) Shutdown() error {
 
 	l.rpc.Shutdown()
 
-	l.ChainNotifier.Stop()
-
 	close(l.quit)
 	l.wg.Wait()
 	return nil
@@ -1251,7 +1224,7 @@ func (l *LightningWallet) handleChannelOpen(req *channelOpenMsg) {
 
 	// Finally, create and officially open the payment channel!
 	// TODO(roasbeef): CreationTime once tx is 'open'
-	channel, _ := NewLightningChannel(l, l.ChainNotifier, l.channelDB,
+	channel, _ := NewLightningChannel(l, l.chainNotifier, l.channelDB,
 		res.partialState)
 
 	res.chanOpen <- channel
@@ -1266,7 +1239,7 @@ func (l *LightningWallet) openChannelAfterConfirmations(res *ChannelReservation)
 	// transaction reaches `numConfs` confirmations.
 	txid := res.fundingTx.TxSha()
 	numConfs := uint32(res.numConfsToOpen)
-	confNtfn, _ := l.ChainNotifier.RegisterConfirmationsNtfn(&txid, numConfs)
+	confNtfn, _ := l.chainNotifier.RegisterConfirmationsNtfn(&txid, numConfs)
 
 	walletLog.Infof("Waiting for funding tx (txid: %v) to reach %v confirmations",
 		txid, numConfs)
@@ -1293,7 +1266,7 @@ out:
 
 	// Finally, create and officially open the payment channel!
 	// TODO(roasbeef): CreationTime once tx is 'open'
-	channel, _ := NewLightningChannel(l, l.ChainNotifier, l.channelDB,
+	channel, _ := NewLightningChannel(l, l.chainNotifier, l.channelDB,
 		res.partialState)
 	res.chanOpen <- channel
 }

lnwallet/wallet_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/boltdb/bolt"
+	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/roasbeef/btcd/chaincfg"
 	"github.com/roasbeef/btcutil/txsort"
@@ -338,7 +339,15 @@ func createTestWallet(miningNode *rpctest.Harness, netParams *chaincfg.Params) (
 		return "", nil, err
 	}
 
-	wallet, err := NewLightningWallet(config, cdb)
+	chainNotifier, err := btcdnotify.New(&rpcConfig)
+	if err != nil {
+		return "", nil, err
+	}
+	if err := chainNotifier.Start(); err != nil {
+		return "", nil, err
+	}
+
+	wallet, err := NewLightningWallet(config, cdb, chainNotifier)
 	if err != nil {
 		return "", nil, err
 	}

log.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/btcsuite/btclog"
 	"github.com/btcsuite/seelog"
-	"github.com/lightningnetwork/lnd/chainntfs"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )

peer.go

@@ -218,7 +218,7 @@ func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) error {
 	for _, dbChan := range chans {
 		chanID := dbChan.ChanID
 		lnChan, err := lnwallet.NewLightningChannel(p.server.lnwallet,
-			p.server.lnwallet.ChainNotifier, p.server.chanDB, dbChan)
+			p.server.chainNotifier, p.server.chanDB, dbChan)
 		if err != nil {
 			return err
 		}
@@ -673,8 +673,7 @@ func (p *peer) handleLocalClose(req *closeLinkReq) {
 	// confirmation.
 	go func() {
 		// TODO(roasbeef): add param for num needed confs
-		notifier := p.server.lnwallet.ChainNotifier
-		confNtfn, err := notifier.RegisterConfirmationsNtfn(txid, 1)
+		confNtfn, err := p.server.chainNotifier.RegisterConfirmationsNtfn(txid, 1)
 		if err != nil {
 			req.err <- err
 			return

server.go

@@ -8,6 +8,7 @@ import (
 	"sync/atomic"
 
 	"github.com/btcsuite/fastsha256"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lndc"
 	"github.com/lightningnetwork/lnd/lnrpc"
@@ -40,9 +41,9 @@ type server struct {
 	listeners []net.Listener
 	peers     map[int32]*peer
 
-	rpcServer *rpcServer
-	// TODO(roasbeef): add chan notifier also
-	lnwallet *lnwallet.LightningWallet
+	rpcServer     *rpcServer
+	chainNotifier chainntnfs.ChainNotifier
+	lnwallet      *lnwallet.LightningWallet
 
 	// TODO(roasbeef): add to constructor
 	fundingMgr *fundingManager
@@ -63,8 +64,8 @@ type server struct {
 
 // newServer creates a new instance of the server which is to listen using the
 // passed listener address.
-func newServer(listenAddrs []string, wallet *lnwallet.LightningWallet,
-	chanDB *channeldb.DB) (*server, error) {
+func newServer(listenAddrs []string, notifier chainntnfs.ChainNotifier,
+	wallet *lnwallet.LightningWallet, chanDB *channeldb.DB) (*server, error) {
 
 	privKey, err := getIdentityPrivKey(chanDB, wallet)
 	if err != nil {
@@ -81,19 +82,20 @@ func newServer(listenAddrs []string, wallet *lnwallet.LightningWallet,
 
 	serializedPubKey := privKey.PubKey().SerializeCompressed()
 	s := &server{
-		chanDB:       chanDB,
-		fundingMgr:   newFundingManager(wallet),
-		htlcSwitch:   newHtlcSwitch(),
-		invoices:     newInvoiceRegistry(),
-		lnwallet:     wallet,
-		identityPriv: privKey,
-		lightningID:  fastsha256.Sum256(serializedPubKey),
-		listeners:    listeners,
-		peers:        make(map[int32]*peer),
-		newPeers:     make(chan *peer, 100),
-		donePeers:    make(chan *peer, 100),
-		queries:      make(chan interface{}),
-		quit:         make(chan struct{}),
+		chainNotifier: notifier,
+		chanDB:        chanDB,
+		fundingMgr:    newFundingManager(wallet),
+		htlcSwitch:    newHtlcSwitch(),
+		invoices:      newInvoiceRegistry(),
+		lnwallet:      wallet,
+		identityPriv:  privKey,
+		lightningID:   fastsha256.Sum256(serializedPubKey),
+		listeners:     listeners,
+		peers:         make(map[int32]*peer),
+		newPeers:      make(chan *peer, 100),
+		donePeers:     make(chan *peer, 100),
+		queries:       make(chan interface{}),
+		quit:          make(chan struct{}),
 	}
 
 	// TODO(roasbeef): remove
@@ -110,10 +112,10 @@ func newServer(listenAddrs []string, wallet *lnwallet.LightningWallet,
 
 // Start starts the main daemon server, all requested listeners, and any helper
 // goroutines.
-func (s *server) Start() {
+func (s *server) Start() error {
 	// Already running?
 	if atomic.AddInt32(&s.started, 1) != 1 {
-		return
+		return nil
 	}
 
 	// Start all the listeners.
@@ -122,12 +124,30 @@ func (s *server) Start() {
 		go s.listener(l)
 	}
 
-	s.fundingMgr.Start()
-	s.htlcSwitch.Start()
+	// Start the notification server. This is used so channel managment
+	// goroutines can be notified when a funding transaction reaches a
+	// sufficient number of confirmations, or when the input for the
+	// funding transaction is spent in an attempt at an uncooperative
+	// close by the counter party.
+	if err := s.chainNotifier.Start(); err != nil {
+		return err
+	}
+
+	if err := s.rpcServer.Start(); err != nil {
+		return err
+	}
+	if err := s.fundingMgr.Start(); err != nil {
+		return err
+	}
+	if err := s.htlcSwitch.Start(); err != nil {
+		return err
+	}
 	s.routingMgr.Start()
 
 	s.wg.Add(1)
 	go s.queryHandler()
+
+	return nil
 }
 
 // Stop gracefully shutsdown the main daemon server. This function will signal
@@ -146,10 +166,14 @@ func (s *server) Stop() error {
 		}
 	}
 
+	// Shutdown the wallet, funding manager, and the rpc server.
+	s.chainNotifier.Stop()
 	s.rpcServer.Stop()
-	s.lnwallet.Shutdown()
 	s.fundingMgr.Stop()
 	s.routingMgr.Stop()
+	s.htlcSwitch.Stop()
+
+	s.lnwallet.Shutdown()
 
 	// Signal all the lingering goroutines to quit.
 	close(s.quit)