func readWAL(waldir string, snap walpb.Snapshot) (w *wal.WAL, id, cid types.ID, st raftpb.HardState, ents []raftpb.Entry) {
var (
err error
wmetadata []byte
)
repaired := false
for {
if w, err = wal.Open(waldir, snap); err != nil {
plog.Fatalf("open wal error: %v", err)
}
if wmetadata, st, ents, err = w.ReadAll(); err != nil {
w.Close()
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
plog.Fatalf("read wal error (%v) and cannot be repaired", err)
}
if !wal.Repair(waldir) {
plog.Fatalf("WAL error (%v) cannot be repaired", err)
} else {
plog.Infof("repaired WAL error (%v)", err)
repaired = true
}
continue
}
break
}
var metadata pb.Metadata
pbutil.MustUnmarshal(&metadata, wmetadata)
id = types.ID(metadata.NodeID)
cid = types.ID(metadata.ClusterID)
return
}
// ReadRepairWAL opens a WAL for reading, and attempts to read it. If we can't read it, attempts to repair
// and read again.
func ReadRepairWAL(
ctx context.Context,
walDir string,
walsnap walpb.Snapshot,
factory WALFactory,
) (WAL, WALData, error) {
var (
reader WAL
metadata []byte
st raftpb.HardState
ents []raftpb.Entry
err error
)
repaired := false
for {
if reader, err = factory.Open(walDir, walsnap); err != nil {
return nil, WALData{}, errors.Wrap(err, "failed to open WAL")
}
if metadata, st, ents, err = reader.ReadAll(); err != nil {
if closeErr := reader.Close(); closeErr != nil {
return nil, WALData{}, closeErr
}
if _, ok := err.(encryption.ErrCannotDecrypt); ok {
return nil, WALData{}, errors.Wrap(err, "failed to decrypt WAL")
}
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
return nil, WALData{}, errors.Wrap(err, "irreparable WAL error")
}
if !wal.Repair(walDir) {
return nil, WALData{}, errors.Wrap(err, "WAL error cannot be repaired")
}
log.G(ctx).WithError(err).Info("repaired WAL error")
repaired = true
continue
}
break
}
return reader, WALData{
Metadata: metadata,
HardState: st,
Entries: ents,
}, nil
}
func (n *Node) readWAL(ctx context.Context, snapshot *raftpb.Snapshot, forceNewCluster bool) (err error) {
var (
walsnap walpb.Snapshot
metadata []byte
st raftpb.HardState
ents []raftpb.Entry
)
if snapshot != nil {
walsnap.Index = snapshot.Metadata.Index
walsnap.Term = snapshot.Metadata.Term
}
repaired := false
for {
if n.wal, err = wal.Open(n.walDir(), walsnap); err != nil {
return fmt.Errorf("open WAL error: %v", err)
}
if metadata, st, ents, err = n.wal.ReadAll(); err != nil {
if err := n.wal.Close(); err != nil {
return err
}
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
return fmt.Errorf("read WAL error (%v) and cannot be repaired", err)
}
if !wal.Repair(n.walDir()) {
return fmt.Errorf("WAL error (%v) cannot be repaired", err)
}
log.G(ctx).Infof("repaired WAL error (%v)", err)
repaired = true
continue
}
break
}
defer func() {
if err != nil {
if walErr := n.wal.Close(); walErr != nil {
n.Config.Logger.Errorf("error closing raft WAL: %v", walErr)
}
}
}()
var raftNode api.RaftMember
if err := raftNode.Unmarshal(metadata); err != nil {
return fmt.Errorf("error unmarshalling WAL metadata: %v", err)
}
n.Config.ID = raftNode.RaftID
// All members that are no longer part of the cluster must be added to
// the removed list right away, so that we don't try to connect to them
// before processing the configuration change entries, which could make
// us get stuck.
for _, ent := range ents {
if ent.Index <= st.Commit && ent.Type == raftpb.EntryConfChange {
var cc raftpb.ConfChange
if err := cc.Unmarshal(ent.Data); err != nil {
return fmt.Errorf("error unmarshalling config change: %v", err)
}
if cc.Type == raftpb.ConfChangeRemoveNode {
n.cluster.RemoveMember(cc.NodeID)
}
}
}
if forceNewCluster {
// discard the previously uncommitted entries
for i, ent := range ents {
if ent.Index > st.Commit {
log.G(context.Background()).Infof("discarding %d uncommitted WAL entries ", len(ents)-i)
ents = ents[:i]
break
}
}
// force append the configuration change entries
toAppEnts := createConfigChangeEnts(getIDs(snapshot, ents), uint64(n.Config.ID), st.Term, st.Commit)
// All members that are being removed as part of the
// force-new-cluster process must be added to the
// removed list right away, so that we don't try to
// connect to them before processing the configuration
// change entries, which could make us get stuck.
for _, ccEnt := range toAppEnts {
if ccEnt.Type == raftpb.EntryConfChange {
var cc raftpb.ConfChange
if err := cc.Unmarshal(ccEnt.Data); err != nil {
return fmt.Errorf("error unmarshalling force-new-cluster config change: %v", err)
}
if cc.Type == raftpb.ConfChangeRemoveNode {
n.cluster.RemoveMember(cc.NodeID)
}
}
}
ents = append(ents, toAppEnts...)
// force commit newly appended entries
err := n.wal.Save(st, toAppEnts)
if err != nil {
log.G(context.Background()).Fatalf("%v", err)
}
if len(toAppEnts) != 0 {
st.Commit = toAppEnts[len(toAppEnts)-1].Index
}
}
if snapshot != nil {
if err := n.raftStore.ApplySnapshot(*snapshot); err != nil {
return err
}
}
if err := n.raftStore.SetHardState(st); err != nil {
return err
}
if err := n.raftStore.Append(ents); err != nil {
return err
}
return nil
}
func (n *Node) readWAL(ctx context.Context, snapshot *raftpb.Snapshot, forceNewCluster bool) (err error) {
var (
walsnap walpb.Snapshot
metadata []byte
st raftpb.HardState
ents []raftpb.Entry
)
if snapshot != nil {
walsnap.Index = snapshot.Metadata.Index
walsnap.Term = snapshot.Metadata.Term
}
repaired := false
for {
if n.wal, err = wal.Open(n.walDir(), walsnap); err != nil {
return fmt.Errorf("open wal error: %v", err)
}
if metadata, st, ents, err = n.wal.ReadAll(); err != nil {
if err := n.wal.Close(); err != nil {
return err
}
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
return fmt.Errorf("read wal error (%v) and cannot be repaired", err)
}
if !wal.Repair(n.walDir()) {
return fmt.Errorf("WAL error (%v) cannot be repaired", err)
}
log.G(ctx).Infof("repaired WAL error (%v)", err)
repaired = true
continue
}
break
}
defer func() {
if err != nil {
if walErr := n.wal.Close(); walErr != nil {
n.Config.Logger.Errorf("error closing raft WAL: %v", walErr)
}
}
}()
var raftNode api.RaftMember
if err := raftNode.Unmarshal(metadata); err != nil {
return fmt.Errorf("error unmarshalling wal metadata: %v", err)
}
n.Config.ID = raftNode.RaftID
if forceNewCluster {
// discard the previously uncommitted entries
for i, ent := range ents {
if ent.Index > st.Commit {
log.G(context.Background()).Infof("discarding %d uncommitted WAL entries ", len(ents)-i)
ents = ents[:i]
break
}
}
// force append the configuration change entries
toAppEnts := createConfigChangeEnts(getIDs(snapshot, ents), uint64(n.Config.ID), st.Term, st.Commit)
ents = append(ents, toAppEnts...)
// force commit newly appended entries
err := n.wal.Save(st, toAppEnts)
if err != nil {
log.G(context.Background()).Fatalf("%v", err)
}
if len(toAppEnts) != 0 {
st.Commit = toAppEnts[len(toAppEnts)-1].Index
}
}
if snapshot != nil {
if err := n.raftStore.ApplySnapshot(*snapshot); err != nil {
return err
}
}
if err := n.raftStore.SetHardState(st); err != nil {
return err
}
if err := n.raftStore.Append(ents); err != nil {
return err
}
return nil
}