channeldb+migration27: patch balance fields for historical chan

This commit adds a new migration to patch the two balance fields,
`InitialLocalBalance` and `InitialRemoteBalance` for the historical
channels. Because they are not saved previously, for historical channels
prior to the revocation log PR, these fields will be empty.

Author: yyforyongyu

channeldb/db.go

@@ -21,6 +21,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb/migration24"
 	"github.com/lightningnetwork/lnd/channeldb/migration25"
 	"github.com/lightningnetwork/lnd/channeldb/migration26"
+	"github.com/lightningnetwork/lnd/channeldb/migration27"
 	"github.com/lightningnetwork/lnd/channeldb/migration_01_to_11"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -219,6 +220,12 @@ var (
 			number:    26,
 			migration: migration26.MigrateBalancesToTlvRecords,
 		},
+		{
+			// Patch the initial local/remote balance fields with
+			// empty values for historical channels.
+			number:    27,
+			migration: migration27.MigrateHistoricalBalances,
+		},
 	}
 
 	// Big endian is the preferred byte order, due to cursor scans over

channeldb/migration27/channel.go

@@ -0,0 +1,233 @@
+package migration27
+
+import (
+	"bytes"
+	"fmt"
+
+	lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
+	mig25 "github.com/lightningnetwork/lnd/channeldb/migration25"
+	mig26 "github.com/lightningnetwork/lnd/channeldb/migration26"
+	mig "github.com/lightningnetwork/lnd/channeldb/migration_01_to_11"
+	"github.com/lightningnetwork/lnd/kvdb"
+	"github.com/lightningnetwork/lnd/tlv"
+)
+
+const (
+	// A tlv type definition used to serialize and deserialize a KeyLocator
+	// from the database.
+	keyLocType tlv.Type = 1
+
+	// A tlv type used to serialize and deserialize the
+	// `InitialLocalBalance` field.
+	initialLocalBalanceType tlv.Type = 2
+
+	// A tlv type used to serialize and deserialize the
+	// `InitialRemoteBalance` field.
+	initialRemoteBalanceType tlv.Type = 3
+)
+
+var (
+	// chanInfoKey can be accessed within the bucket for a channel
+	// (identified by its chanPoint). This key stores all the static
+	// information for a channel which is decided at the end of  the
+	// funding flow.
+	chanInfoKey = []byte("chan-info-key")
+
+	// localUpfrontShutdownKey can be accessed within the bucket for a
+	// channel (identified by its chanPoint). This key stores an optional
+	// upfront shutdown script for the local peer.
+	localUpfrontShutdownKey = []byte("local-upfront-shutdown-key")
+
+	// remoteUpfrontShutdownKey can be accessed within the bucket for a
+	// channel (identified by its chanPoint). This key stores an optional
+	// upfront shutdown script for the remote peer.
+	remoteUpfrontShutdownKey = []byte("remote-upfront-shutdown-key")
+
+	// lastWasRevokeKey is a key that stores true when the last update we
+	// sent was a revocation and false when it was a commitment signature.
+	// This is nil in the case of new channels with no updates exchanged.
+	lastWasRevokeKey = []byte("last-was-revoke")
+
+	// ErrNoChanInfoFound is returned when a particular channel does not
+	// have any channels state.
+	ErrNoChanInfoFound = fmt.Errorf("no chan info found")
+)
+
+// OpenChannel embeds a mig26.OpenChannel with the extra update-to-date
+// serialization and deserialization methods.
+//
+// NOTE: doesn't have the Packager field as it's not used in current migration.
+type OpenChannel struct {
+	mig26.OpenChannel
+
+	// chanStatus is the current status of this channel. If it is not in
+	// the state Default, it should not be used for forwarding payments.
+	chanStatus mig25.ChannelStatus
+}
+
+// FetchChanInfo deserializes the channel info based on the legacy boolean.
+func FetchChanInfo(chanBucket kvdb.RBucket, c *OpenChannel, legacy bool) error {
+	infoBytes := chanBucket.Get(chanInfoKey)
+	if infoBytes == nil {
+		return ErrNoChanInfoFound
+	}
+	r := bytes.NewReader(infoBytes)
+
+	var (
+		chanType   mig.ChannelType
+		chanStatus mig.ChannelStatus
+	)
+
+	if err := mig.ReadElements(r,
+		&chanType, &c.ChainHash, &c.FundingOutpoint,
+		&c.ShortChannelID, &c.IsPending, &c.IsInitiator,
+		&chanStatus, &c.FundingBroadcastHeight,
+		&c.NumConfsRequired, &c.ChannelFlags,
+		&c.IdentityPub, &c.Capacity, &c.TotalMSatSent,
+		&c.TotalMSatReceived,
+	); err != nil {
+		return fmt.Errorf("ReadElements got: %v", err)
+	}
+
+	c.ChanType = mig25.ChannelType(chanType)
+	c.chanStatus = mig25.ChannelStatus(chanStatus)
+
+	// For single funder channels that we initiated and have the funding
+	// transaction to, read the funding txn.
+	if c.FundingTxPresent() {
+		if err := mig.ReadElement(r, &c.FundingTxn); err != nil {
+			return fmt.Errorf("read FundingTxn got: %v", err)
+		}
+	}
+
+	if err := mig.ReadChanConfig(r, &c.LocalChanCfg); err != nil {
+		return fmt.Errorf("read LocalChanCfg got: %v", err)
+	}
+	if err := mig.ReadChanConfig(r, &c.RemoteChanCfg); err != nil {
+		return fmt.Errorf("read RemoteChanCfg got: %v", err)
+	}
+
+	// Retrieve the boolean stored under lastWasRevokeKey.
+	lastWasRevokeBytes := chanBucket.Get(lastWasRevokeKey)
+	if lastWasRevokeBytes == nil {
+		// If nothing has been stored under this key, we store false in
+		// the OpenChannel struct.
+		c.LastWasRevoke = false
+	} else {
+		// Otherwise, read the value into the LastWasRevoke field.
+		revokeReader := bytes.NewReader(lastWasRevokeBytes)
+		err := mig.ReadElements(revokeReader, &c.LastWasRevoke)
+		if err != nil {
+			return fmt.Errorf("read LastWasRevoke got: %v", err)
+		}
+	}
+
+	// Make the tlv stream based on the legacy param.
+	var (
+		ts            *tlv.Stream
+		err           error
+		localBalance  uint64
+		remoteBalance uint64
+	)
+
+	keyLocRecord := mig25.MakeKeyLocRecord(
+		keyLocType, &c.RevocationKeyLocator,
+	)
+
+	// If it's legacy, create the stream with a single tlv record.
+	if legacy {
+		ts, err = tlv.NewStream(keyLocRecord)
+	} else {
+		// Otherwise, for the new format, we will encode the balance
+		// fields in the tlv stream too.
+		ts, err = tlv.NewStream(
+			keyLocRecord,
+			tlv.MakePrimitiveRecord(
+				initialLocalBalanceType, &localBalance,
+			),
+			tlv.MakePrimitiveRecord(
+				initialRemoteBalanceType, &remoteBalance,
+			),
+		)
+	}
+	if err != nil {
+		return fmt.Errorf("create tlv stream got: %v", err)
+	}
+
+	if err := ts.Decode(r); err != nil {
+		return fmt.Errorf("decode tlv stream got: %v", err)
+	}
+
+	// For the new format, attach the balance fields.
+	if !legacy {
+		c.InitialLocalBalance = lnwire.MilliSatoshi(localBalance)
+		c.InitialRemoteBalance = lnwire.MilliSatoshi(remoteBalance)
+	}
+
+	// Finally, read the optional shutdown scripts.
+	if err := mig25.GetOptionalUpfrontShutdownScript(
+		chanBucket, localUpfrontShutdownKey, &c.LocalShutdownScript,
+	); err != nil {
+		return fmt.Errorf("local shutdown script got: %v", err)
+	}
+
+	return mig25.GetOptionalUpfrontShutdownScript(
+		chanBucket, remoteUpfrontShutdownKey, &c.RemoteShutdownScript,
+	)
+}
+
+// PutChanInfo serializes the channel info based on the legacy boolean.
+func PutChanInfo(chanBucket kvdb.RwBucket, c *OpenChannel, legacy bool) error {
+	var w bytes.Buffer
+	if err := mig.WriteElements(&w,
+		mig.ChannelType(c.ChanType), c.ChainHash, c.FundingOutpoint,
+		c.ShortChannelID, c.IsPending, c.IsInitiator,
+		mig.ChannelStatus(c.chanStatus), c.FundingBroadcastHeight,
+		c.NumConfsRequired, c.ChannelFlags,
+		c.IdentityPub, c.Capacity, c.TotalMSatSent,
+		c.TotalMSatReceived,
+	); err != nil {
+		return err
+	}
+
+	// For single funder channels that we initiated, and we have the
+	// funding transaction, then write the funding txn.
+	if c.FundingTxPresent() {
+		if err := mig.WriteElement(&w, c.FundingTxn); err != nil {
+			return err
+		}
+	}
+
+	if err := mig.WriteChanConfig(&w, &c.LocalChanCfg); err != nil {
+		return err
+	}
+	if err := mig.WriteChanConfig(&w, &c.RemoteChanCfg); err != nil {
+		return err
+	}
+
+	// Make the tlv stream based on the legacy param.
+	tlvStream, err := mig26.MakeTlvStream(&c.OpenChannel, legacy)
+	if err != nil {
+		return err
+	}
+
+	if err := tlvStream.Encode(&w); err != nil {
+		return err
+	}
+
+	if err := chanBucket.Put(chanInfoKey, w.Bytes()); err != nil {
+		return err
+	}
+
+	// Finally, add optional shutdown scripts for the local and remote peer
+	// if they are present.
+	if err := mig25.PutOptionalUpfrontShutdownScript(
+		chanBucket, localUpfrontShutdownKey, c.LocalShutdownScript,
+	); err != nil {
+		return err
+	}
+
+	return mig25.PutOptionalUpfrontShutdownScript(
+		chanBucket, remoteUpfrontShutdownKey, c.RemoteShutdownScript,
+	)
+}

channeldb/migration27/log.go

@@ -0,0 +1,14 @@
+package migration27
+
+import (
+	"github.com/btcsuite/btclog"
+)
+
+// log is a logger that is initialized as disabled.  This means the package will
+// not perform any logging by default until a logger is set.
+var log = btclog.Disabled
+
+// UseLogger uses a specified Logger to output package logging info.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}