multi: extract address source into interface

As a preparation to have the method for querying the addresses of a node
separate from the channel state, we extract that method out into its own
interface.

chanbackup/backup.go

@@ -21,7 +21,11 @@ type LiveChannelSource interface {
 	// passed chanPoint. Optionally an existing db tx can be supplied.
 	FetchChannel(tx kvdb.RTx, chanPoint wire.OutPoint) (
 		*channeldb.OpenChannel, error)
+}
 
+// AddressSource is an interface that allows us to query for the set of
+// addresses a node can be connected to.
+type AddressSource interface {
 	// AddrsForNode returns all known addresses for the target node public
 	// key.
 	AddrsForNode(nodePub *btcec.PublicKey) ([]net.Addr, error)
@@ -31,15 +35,15 @@ type LiveChannelSource interface {
 // passed open channel. The backup includes all information required to restore
 // the channel, as well as addressing information so we can find the peer and
 // reconnect to them to initiate the protocol.
-func assembleChanBackup(chanSource LiveChannelSource,
+func assembleChanBackup(addrSource AddressSource,
 	openChan *channeldb.OpenChannel) (*Single, error) {
 
 	log.Debugf("Crafting backup for ChannelPoint(%v)",
 		openChan.FundingOutpoint)
 
 	// First, we'll query the channel source to obtain all the addresses
-	// that are are associated with the peer for this channel.
-	nodeAddrs, err := chanSource.AddrsForNode(openChan.IdentityPub)
+	// that are associated with the peer for this channel.
+	nodeAddrs, err := addrSource.AddrsForNode(openChan.IdentityPub)
 	if err != nil {
 		return nil, err
 	}
@@ -52,8 +56,8 @@ func assembleChanBackup(chanSource LiveChannelSource,
 // FetchBackupForChan attempts to create a plaintext static channel backup for
 // the target channel identified by its channel point. If we're unable to find
 // the target channel, then an error will be returned.
-func FetchBackupForChan(chanPoint wire.OutPoint,
-	chanSource LiveChannelSource) (*Single, error) {
+func FetchBackupForChan(chanPoint wire.OutPoint, chanSource LiveChannelSource,
+	addrSource AddressSource) (*Single, error) {
 
 	// First, we'll query the channel source to see if the channel is known
 	// and open within the database.
@@ -66,7 +70,7 @@ func FetchBackupForChan(chanPoint wire.OutPoint,
 
 	// Once we have the target channel, we can assemble the backup using
 	// the source to obtain any extra information that we may need.
-	staticChanBackup, err := assembleChanBackup(chanSource, targetChan)
+	staticChanBackup, err := assembleChanBackup(addrSource, targetChan)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create chan backup: %v", err)
 	}
@@ -76,7 +80,9 @@ func FetchBackupForChan(chanPoint wire.OutPoint,
 
 // FetchStaticChanBackups will return a plaintext static channel back up for
 // all known active/open channels within the passed channel source.
-func FetchStaticChanBackups(chanSource LiveChannelSource) ([]Single, error) {
+func FetchStaticChanBackups(chanSource LiveChannelSource,
+	addrSource AddressSource) ([]Single, error) {
+
 	// First, we'll query the backup source for information concerning all
 	// currently open and available channels.
 	openChans, err := chanSource.FetchAllChannels()
@@ -89,7 +95,7 @@ func FetchStaticChanBackups(chanSource LiveChannelSource) ([]Single, error) {
 	// channel.
 	staticChanBackups := make([]Single, 0, len(openChans))
 	for _, openChan := range openChans {
-		chanBackup, err := assembleChanBackup(chanSource, openChan)
+		chanBackup, err := assembleChanBackup(addrSource, openChan)
 		if err != nil {
 			return nil, err
 		}

chanbackup/backup_test.go

@@ -124,7 +124,9 @@ func TestFetchBackupForChan(t *testing.T) {
 		},
 	}
 	for i, testCase := range testCases {
-		_, err := FetchBackupForChan(testCase.chanPoint, chanSource)
+		_, err := FetchBackupForChan(
+			testCase.chanPoint, chanSource, chanSource,
+		)
 		switch {
 		// If this is a valid test case, and we failed, then we'll
 		// return an error.
@@ -167,7 +169,7 @@ func TestFetchStaticChanBackups(t *testing.T) {
 	// With the channel source populated, we'll now attempt to create a set
 	// of backups for all the channels. This should succeed, as all items
 	// are populated within the channel source.
-	backups, err := FetchStaticChanBackups(chanSource)
+	backups, err := FetchStaticChanBackups(chanSource, chanSource)
 	if err != nil {
 		t.Fatalf("unable to create chan back ups: %v", err)
 	}
@@ -184,7 +186,7 @@ func TestFetchStaticChanBackups(t *testing.T) {
 	copy(n[:], randomChan2.IdentityPub.SerializeCompressed())
 	delete(chanSource.addrs, n)
 
-	_, err = FetchStaticChanBackups(chanSource)
+	_, err = FetchStaticChanBackups(chanSource, chanSource)
 	if err == nil {
 		t.Fatalf("query with incomplete information should fail")
 	}
@@ -193,7 +195,7 @@ func TestFetchStaticChanBackups(t *testing.T) {
 	// source at all, then we'll fail as well.
 	chanSource = newMockChannelSource()
 	chanSource.failQuery = true
-	_, err = FetchStaticChanBackups(chanSource)
+	_, err = FetchStaticChanBackups(chanSource, chanSource)
 	if err == nil {
 		t.Fatalf("query should fail")
 	}

rpcserver.go

@@ -6469,7 +6469,7 @@ func (r *rpcServer) ExportChannelBackup(ctx context.Context,
 	// the database. If this channel has been closed, or the outpoint is
 	// unknown, then we'll return an error
 	unpackedBackup, err := chanbackup.FetchBackupForChan(
-		chanPoint, r.server.chanStateDB,
+		chanPoint, r.server.chanStateDB, r.server.addrSource,
 	)
 	if err != nil {
 		return nil, err
@@ -6639,7 +6639,7 @@ func (r *rpcServer) ExportAllChannelBackups(ctx context.Context,
 	// First, we'll attempt to read back ups for ALL currently opened
 	// channels from disk.
 	allUnpackedBackups, err := chanbackup.FetchStaticChanBackups(
-		r.server.chanStateDB,
+		r.server.chanStateDB, r.server.addrSource,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("unable to fetch all static chan "+
@@ -6766,7 +6766,7 @@ func (r *rpcServer) SubscribeChannelBackups(req *lnrpc.ChannelBackupSubscription
 			// we'll obtains the current set of single channel
 			// backups from disk.
 			chanBackups, err := chanbackup.FetchStaticChanBackups(
-				r.server.chanStateDB,
+				r.server.chanStateDB, r.server.addrSource,
 			)
 			if err != nil {
 				return fmt.Errorf("unable to fetch all "+

server.go

@@ -224,6 +224,8 @@ type server struct {
 
 	chanStateDB *channeldb.DB
 
+	addrSource chanbackup.AddressSource
+
 	htlcSwitch *htlcswitch.Switch
 
 	interceptableSwitch *htlcswitch.InterceptableSwitch
@@ -433,6 +435,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		cfg:            cfg,
 		graphDB:        dbs.graphDB.ChannelGraph(),
 		chanStateDB:    dbs.chanStateDB,
+		addrSource:     dbs.chanStateDB,
 		cc:             cc,
 		sigPool:        lnwallet.NewSigPool(cfg.Workers.Sig, cc.Signer),
 		writePool:      writePool,
@@ -1246,7 +1249,9 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		addrs:        s.chanStateDB,
 	}
 	backupFile := chanbackup.NewMultiFile(cfg.BackupFilePath)
-	startingChans, err := chanbackup.FetchStaticChanBackups(s.chanStateDB)
+	startingChans, err := chanbackup.FetchStaticChanBackups(
+		s.chanStateDB, s.addrSource,
+	)
 	if err != nil {
 		return nil, err
 	}