agola/internal/objectstorage/common/atomic.go
Simone Gotti b3867fb7ca objectstorage: add posix standard storage
rename the previous posix storage to posixflat and make it currently not user
selectable (since I'm not sure it's really worth using it).

The new posix storage uses the filesystem without any escaping so it's not a
real flat namespace.

This isn't a real issue since also minio is not a flat namespace and we are so
forced to use it like a hierarchycal filesystem.
2019-05-21 15:17:53 +02:00

85 lines
2.0 KiB
Go

// Copyright 2019 Sorint.lab
//
// 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 common
import (
"io"
"io/ioutil"
"os"
"path/filepath"
"strings"
)
// WriteFileAtomicFunc atomically writes a file, it achieves this by creating a
// temporary file and then moving it. writeFunc is the func that will write
// data to the file.
// TODO(sgotti) remove left over tmp files if process crashes before calling
// os.Remove
func WriteFileAtomicFunc(p, baseDir, tmpDir string, perm os.FileMode, persist bool, writeFunc func(f io.Writer) error) error {
f, err := ioutil.TempFile(tmpDir, "tmpfile")
if err != nil {
return err
}
err = writeFunc(f)
if persist && err == nil {
err = f.Sync()
}
if closeErr := f.Close(); err == nil {
err = closeErr
}
if permErr := os.Chmod(f.Name(), perm); err == nil {
err = permErr
}
if err == nil {
err = os.Rename(f.Name(), p)
}
if err != nil {
os.Remove(f.Name())
return err
}
if !persist {
return nil
}
// sync parent dirs
pdir := filepath.Dir(p)
for {
if !strings.HasPrefix(pdir, baseDir) {
break
}
f, err := os.Open(pdir)
if err != nil {
f.Close()
return nil
}
if err := f.Sync(); err != nil {
f.Close()
return nil
}
f.Close()
pdir = filepath.Dir(pdir)
}
return nil
}
func WriteFileAtomic(filename, baseDir, tmpDir string, perm os.FileMode, persist bool, data []byte) error {
return WriteFileAtomicFunc(filename, baseDir, tmpDir, perm, persist,
func(f io.Writer) error {
_, err := f.Write(data)
return err
})
}