k3s/vendor/go.etcd.io/etcd/etcdserver/api/snap/db.go

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2020-05-07 05:09:19 +00:00
// Copyright 2015 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package snap
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"time"
"go.etcd.io/etcd/pkg/fileutil"
humanize "github.com/dustin/go-humanize"
"go.uber.org/zap"
)
var ErrNoDBSnapshot = errors.New("snap: snapshot file doesn't exist")
// SaveDBFrom saves snapshot of the database from the given reader. It
// guarantees the save operation is atomic.
func (s *Snapshotter) SaveDBFrom(r io.Reader, id uint64) (int64, error) {
start := time.Now()
f, err := ioutil.TempFile(s.dir, "tmp")
if err != nil {
return 0, err
}
var n int64
n, err = io.Copy(f, r)
if err == nil {
fsyncStart := time.Now()
err = fileutil.Fsync(f)
snapDBFsyncSec.Observe(time.Since(fsyncStart).Seconds())
}
f.Close()
if err != nil {
os.Remove(f.Name())
return n, err
}
fn := s.dbFilePath(id)
if fileutil.Exist(fn) {
os.Remove(f.Name())
return n, nil
}
err = os.Rename(f.Name(), fn)
if err != nil {
os.Remove(f.Name())
return n, err
}
if s.lg != nil {
s.lg.Info(
"saved database snapshot to disk",
zap.String("path", fn),
zap.Int64("bytes", n),
zap.String("size", humanize.Bytes(uint64(n))),
)
} else {
plog.Infof("saved database snapshot to disk [total bytes: %d]", n)
}
snapDBSaveSec.Observe(time.Since(start).Seconds())
return n, nil
}
// DBFilePath returns the file path for the snapshot of the database with
// given id. If the snapshot does not exist, it returns error.
func (s *Snapshotter) DBFilePath(id uint64) (string, error) {
if _, err := fileutil.ReadDir(s.dir); err != nil {
return "", err
}
fn := s.dbFilePath(id)
if fileutil.Exist(fn) {
return fn, nil
}
if s.lg != nil {
s.lg.Warn(
"failed to find [SNAPSHOT-INDEX].snap.db",
zap.Uint64("snapshot-index", id),
zap.String("snapshot-file-path", fn),
zap.Error(ErrNoDBSnapshot),
)
}
return "", ErrNoDBSnapshot
}
func (s *Snapshotter) dbFilePath(id uint64) string {
return filepath.Join(s.dir, fmt.Sprintf("%016x.snap.db", id))
}