VictoriaMetrics/lib/backup/actions/restore.go

225 lines
7 KiB
Go

package actions
import (
"fmt"
"io"
"os"
"path"
"sync/atomic"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/backupnames"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/common"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/fslocal"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/metrics"
)
// Restore restores data according to the provided settings.
//
// Note that the restore works only for VictoriaMetrics backups made from snapshots.
// It works improperly on mutable files.
type Restore struct {
// Concurrency is the number of concurrent workers to run during restore.
Concurrency int
// Src is the source containing backed up data.
Src common.RemoteFS
// Dst is destination to restore the data.
//
// If dst points to existing directory, then incremental restore is performed,
// i.e. only new data is downloaded from src.
Dst *fslocal.FS
// SkipBackupCompleteCheck may be set in order to skip for `backup complete` file in Src.
//
// This may be needed for restoring from old backups with missing `backup complete` file.
SkipBackupCompleteCheck bool
}
// Run runs r with the provided settings.
func (r *Restore) Run() error {
startTime := time.Now()
// Make sure VictoriaMetrics doesn't run during the restore process.
fs.MustMkdirIfNotExist(r.Dst.Dir)
flockF := fs.MustCreateFlockFile(r.Dst.Dir)
defer fs.MustClose(flockF)
if err := createRestoreLock(r.Dst.Dir); err != nil {
return err
}
concurrency := r.Concurrency
src := r.Src
dst := r.Dst
if !r.SkipBackupCompleteCheck {
ok, err := src.HasFile(backupnames.BackupCompleteFilename)
if err != nil {
return err
}
if !ok {
return fmt.Errorf("cannot find %s file in %s; this means either incomplete backup or old backup; "+
"pass -skipBackupCompleteCheck command-line flag if you still need restoring from this backup", backupnames.BackupCompleteFilename, src)
}
}
logger.Infof("starting restore from %s to %s", src, dst)
logger.Infof("obtaining list of parts at %s", src)
srcParts, err := src.ListParts()
if err != nil {
return fmt.Errorf("cannot list src parts: %w", err)
}
logger.Infof("obtaining list of parts at %s", dst)
dstParts, err := dst.ListParts()
if err != nil {
return fmt.Errorf("cannot list dst parts: %w", err)
}
backupSize := getPartsSize(srcParts)
// Validate srcParts. They must cover the whole files.
common.SortParts(srcParts)
offset := uint64(0)
var pOld common.Part
var path string
for _, p := range srcParts {
if p.Path != path {
if offset != pOld.FileSize {
return fmt.Errorf("invalid size for %q; got %d; want %d", path, offset, pOld.FileSize)
}
pOld = p
path = p.Path
offset = 0
}
if p.Offset < offset {
return fmt.Errorf("there is an overlap in %d bytes between %s and %s", offset-p.Offset, &pOld, &p)
}
if p.Offset > offset {
if offset == 0 {
return fmt.Errorf("there is a gap in %d bytes from file start to %s", p.Offset, &p)
}
return fmt.Errorf("there is a gap in %d bytes between %s and %s", p.Offset-offset, &pOld, &p)
}
if p.Size != p.ActualSize {
return fmt.Errorf("invalid size for %s; got %d; want %d", &p, p.ActualSize, p.Size)
}
offset += p.Size
}
partsToDelete := common.PartsDifference(dstParts, srcParts)
deleteSize := uint64(0)
if len(partsToDelete) > 0 {
// Remove only files with the missing part at offset 0.
// Assume other files are partially downloaded during the previous Restore.Run call,
// so only the last part in them may be incomplete.
// The last part for partially downloaded files will be re-downloaded later.
// This addresses https://github.com/VictoriaMetrics/VictoriaMetrics/issues/487 .
pathsToDelete := make(map[string]bool)
for _, p := range partsToDelete {
if p.Offset == 0 {
pathsToDelete[p.Path] = true
}
}
logger.Infof("deleting %d files from %s", len(pathsToDelete), dst)
for path := range pathsToDelete {
logger.Infof("deleting %s from %s", path, dst)
size, err := dst.DeletePath(path)
if err != nil {
return fmt.Errorf("cannot delete %s from %s: %w", path, dst, err)
}
deleteSize += size
}
if err := dst.RemoveEmptyDirs(); err != nil {
return fmt.Errorf("cannot remove empty directories at %s: %w", dst, err)
}
}
// Re-read dstParts, since additional parts may be removed on the previous step.
dstParts, err = dst.ListParts()
if err != nil {
return fmt.Errorf("cannot list dst parts after the deletion: %w", err)
}
partsToCopy := common.PartsDifference(srcParts, dstParts)
downloadSize := getPartsSize(partsToCopy)
if len(partsToCopy) > 0 {
perPath := make(map[string][]common.Part)
for _, p := range partsToCopy {
parts := perPath[p.Path]
parts = append(parts, p)
perPath[p.Path] = parts
}
logger.Infof("downloading %d parts from %s to %s", len(partsToCopy), src, dst)
var bytesDownloaded atomic.Uint64
err = runParallelPerPath(concurrency, perPath, func(parts []common.Part) error {
// Sort partsToCopy in order to properly grow file size during downloading
// and to properly resume downloading of incomplete files on the next Restore.Run call.
common.SortParts(parts)
for _, p := range parts {
logger.Infof("downloading %s from %s to %s", &p, src, dst)
wc, err := dst.NewWriteCloser(p)
if err != nil {
return fmt.Errorf("cannot create writer for %q to %s: %w", &p, dst, err)
}
sw := &statWriter{
w: wc,
bytesWritten: &bytesDownloaded,
}
if err := src.DownloadPart(p, sw); err != nil {
return fmt.Errorf("cannot download %s to %s: %w", &p, dst, err)
}
if err := wc.Close(); err != nil {
return fmt.Errorf("cannot close reader from %s from %s: %w", &p, src, err)
}
}
return nil
}, func(elapsed time.Duration) {
n := bytesDownloaded.Load()
prc := 100 * float64(n) / float64(downloadSize)
logger.Infof("downloaded %d out of %d bytes (%.2f%%) from %s to %s in %s", n, downloadSize, prc, src, dst, elapsed)
})
if err != nil {
return err
}
}
logger.Infof("restored %d bytes from backup in %.3f seconds; deleted %d bytes; downloaded %d bytes",
backupSize, time.Since(startTime).Seconds(), deleteSize, downloadSize)
return removeRestoreLock(r.Dst.Dir)
}
type statWriter struct {
w io.Writer
bytesWritten *atomic.Uint64
}
func (sw *statWriter) Write(p []byte) (int, error) {
n, err := sw.w.Write(p)
sw.bytesWritten.Add(uint64(n))
bytesDownloadedTotal.Add(n)
return n, err
}
var bytesDownloadedTotal = metrics.NewCounter(`vm_backups_downloaded_bytes_total`)
func createRestoreLock(dstDir string) error {
lockF := path.Join(dstDir, backupnames.RestoreInProgressFilename)
f, err := os.Create(lockF)
if err != nil {
return fmt.Errorf("cannot create restore lock file %q: %w", lockF, err)
}
return f.Close()
}
func removeRestoreLock(dstDir string) error {
lockF := path.Join(dstDir, backupnames.RestoreInProgressFilename)
if err := os.Remove(lockF); err != nil {
return fmt.Errorf("cannote remove restore lock file %q: %w", lockF, err)
}
return nil
}