func (n *Node) saveSnapshot(snapshot raftpb.Snapshot, keepOldSnapshots uint64) error {
err := n.wal.SaveSnapshot(walpb.Snapshot{
Index: snapshot.Metadata.Index,
Term: snapshot.Metadata.Term,
})
if err != nil {
return err
}
err = n.snapshotter.SaveSnap(snapshot)
if err != nil {
return err
}
err = n.wal.ReleaseLockTo(snapshot.Metadata.Index)
if err != nil {
return err
}
// Delete any older snapshots
curSnapshot := fmt.Sprintf("%016x-%016x%s", snapshot.Metadata.Term, snapshot.Metadata.Index, ".snap")
dirents, err := ioutil.ReadDir(n.snapDir())
if err != nil {
return err
}
var snapshots []string
for _, dirent := range dirents {
if strings.HasSuffix(dirent.Name(), ".snap") {
snapshots = append(snapshots, dirent.Name())
}
}
// Sort snapshot filenames in reverse lexical order
sort.Sort(sort.Reverse(sort.StringSlice(snapshots)))
// Ignore any snapshots that are older than the current snapshot.
// Delete the others. Rather than doing lexical comparisons, we look
// at what exists before/after the current snapshot in the slice.
// This means that if the current snapshot doesn't appear in the
// directory for some strange reason, we won't delete anything, which
// is the safe behavior.
curSnapshotIdx := -1
var (
removeErr error
oldestSnapshot string
)
for i, snapFile := range snapshots {
if curSnapshotIdx >= 0 && i > curSnapshotIdx {
if uint64(i-curSnapshotIdx) > keepOldSnapshots {
err := os.Remove(filepath.Join(n.snapDir(), snapFile))
if err != nil && removeErr == nil {
removeErr = err
}
continue
}
} else if snapFile == curSnapshot {
curSnapshotIdx = i
}
oldestSnapshot = snapFile
}
if removeErr != nil {
return removeErr
}
// Remove any WAL files that only contain data from before the oldest
// remaining snapshot.
if oldestSnapshot == "" {
return nil
}
// Parse index out of oldest snapshot's filename
var snapTerm, snapIndex uint64
_, err = fmt.Sscanf(oldestSnapshot, "%016x-%016x.snap", &snapTerm, &snapIndex)
if err != nil {
return errors.Wrapf(err, "malformed snapshot filename %s", oldestSnapshot)
}
// List the WALs
dirents, err = ioutil.ReadDir(n.walDir())
if err != nil {
return err
}
var wals []string
for _, dirent := range dirents {
if strings.HasSuffix(dirent.Name(), ".wal") {
wals = append(wals, dirent.Name())
}
}
// Sort WAL filenames in lexical order
sort.Sort(sort.StringSlice(wals))
found := false
deleteUntil := -1
for i, walName := range wals {
var walSeq, walIndex uint64
_, err = fmt.Sscanf(walName, "%016x-%016x.wal", &walSeq, &walIndex)
if err != nil {
return errors.Wrapf(err, "could not parse WAL name %s", walName)
}
if walIndex >= snapIndex {
deleteUntil = i - 1
found = true
break
}
}
// If all WAL files started with indices below the oldest snapshot's
// index, we can delete all but the newest WAL file.
if !found && len(wals) != 0 {
deleteUntil = len(wals) - 1
}
for i := 0; i < deleteUntil; i++ {
walPath := filepath.Join(n.walDir(), wals[i])
l, err := fileutil.TryLockFile(walPath, os.O_WRONLY, fileutil.PrivateFileMode)
if err != nil {
return errors.Wrapf(err, "could not lock old WAL file %s for removal", wals[i])
}
err = os.Remove(walPath)
l.Close()
if err != nil {
return errors.Wrapf(err, "error removing old WAL file %s", wals[i])
}
}
return nil
}
func openAtIndex(dirpath string, snap walpb.Snapshot, write bool) (*WAL, error) {
names, err := readWalNames(dirpath)
if err != nil {
return nil, err
}
nameIndex, ok := searchIndex(names, snap.Index)
if !ok || !isValidSeq(names[nameIndex:]) {
return nil, ErrFileNotFound
}
// open the wal files
rcs := make([]io.ReadCloser, 0)
rs := make([]io.Reader, 0)
ls := make([]*fileutil.LockedFile, 0)
for _, name := range names[nameIndex:] {
p := path.Join(dirpath, name)
if write {
l, err := fileutil.TryLockFile(p, os.O_RDWR, fileutil.PrivateFileMode)
if err != nil {
closeAll(rcs...)
return nil, err
}
ls = append(ls, l)
rcs = append(rcs, l)
} else {
rf, err := os.OpenFile(p, os.O_RDONLY, fileutil.PrivateFileMode)
if err != nil {
closeAll(rcs...)
return nil, err
}
ls = append(ls, nil)
rcs = append(rcs, rf)
}
rs = append(rs, rcs[len(rcs)-1])
}
closer := func() error { return closeAll(rcs...) }
// create a WAL ready for reading
w := &WAL{
dir: dirpath,
start: snap,
decoder: newDecoder(rs...),
readClose: closer,
locks: ls,
}
if write {
// write reuses the file descriptors from read; don't close so
// WAL can append without dropping the file lock
w.readClose = nil
if _, _, err := parseWalName(path.Base(w.tail().Name())); err != nil {
closer()
return nil, err
}
w.fp = newFilePipeline(w.dir, SegmentSizeBytes)
}
return w, nil
}
// GC garbage collects snapshots and wals older than the provided index and term
func (e *EncryptedRaftLogger) GC(index uint64, term uint64, keepOldSnapshots uint64) error {
// Delete any older snapshots
curSnapshot := fmt.Sprintf("%016x-%016x%s", term, index, ".snap")
snapshots, err := ListSnapshots(e.snapDir())
if err != nil {
return err
}
// Ignore any snapshots that are older than the current snapshot.
// Delete the others. Rather than doing lexical comparisons, we look
// at what exists before/after the current snapshot in the slice.
// This means that if the current snapshot doesn't appear in the
// directory for some strange reason, we won't delete anything, which
// is the safe behavior.
curSnapshotIdx := -1
var (
removeErr error
oldestSnapshot string
)
for i, snapFile := range snapshots {
if curSnapshotIdx >= 0 && i > curSnapshotIdx {
if uint64(i-curSnapshotIdx) > keepOldSnapshots {
err := os.Remove(filepath.Join(e.snapDir(), snapFile))
if err != nil && removeErr == nil {
removeErr = err
}
continue
}
} else if snapFile == curSnapshot {
curSnapshotIdx = i
}
oldestSnapshot = snapFile
}
if removeErr != nil {
return removeErr
}
// Remove any WAL files that only contain data from before the oldest
// remaining snapshot.
if oldestSnapshot == "" {
return nil
}
// Parse index out of oldest snapshot's filename
var snapTerm, snapIndex uint64
_, err = fmt.Sscanf(oldestSnapshot, "%016x-%016x.snap", &snapTerm, &snapIndex)
if err != nil {
return errors.Wrapf(err, "malformed snapshot filename %s", oldestSnapshot)
}
wals, err := ListWALs(e.walDir())
if err != nil {
return err
}
found := false
deleteUntil := -1
for i, walName := range wals {
var walSeq, walIndex uint64
_, err = fmt.Sscanf(walName, "%016x-%016x.wal", &walSeq, &walIndex)
if err != nil {
return errors.Wrapf(err, "could not parse WAL name %s", walName)
}
if walIndex >= snapIndex {
deleteUntil = i - 1
found = true
break
}
}
// If all WAL files started with indices below the oldest snapshot's
// index, we can delete all but the newest WAL file.
if !found && len(wals) != 0 {
deleteUntil = len(wals) - 1
}
for i := 0; i < deleteUntil; i++ {
walPath := filepath.Join(e.walDir(), wals[i])
l, err := fileutil.TryLockFile(walPath, os.O_WRONLY, fileutil.PrivateFileMode)
if err != nil {
return errors.Wrapf(err, "could not lock old WAL file %s for removal", wals[i])
}
err = os.Remove(walPath)
l.Close()
if err != nil {
return errors.Wrapf(err, "error removing old WAL file %s", wals[i])
}
}
return nil
}
