prometheus/fileutil/fileutil.go

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// Copyright 2018 The Prometheus 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.
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// Package fileutil provides utility methods used when dealing with the filesystem in tsdb.
// It is largely copied from github.com/coreos/etcd/pkg/fileutil to avoid the
// dependency chain it brings with it.
// Please check github.com/coreos/etcd for licensing information.
package fileutil
import (
"io/ioutil"
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"os"
"path/filepath"
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"sort"
"strings"
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)
// CopyDirs copies all directories, subdirectories and files recursively including the empty folders.
// Source and destination must be full paths.
func CopyDirs(src, dest string) error {
if err := os.MkdirAll(dest, 0777); err != nil {
return err
}
files, err := readDirs(src)
if err != nil {
return err
}
for _, f := range files {
dp := filepath.Join(dest, f)
sp := filepath.Join(src, f)
stat, err := os.Stat(sp)
if err != nil {
return err
}
// Empty directories are also created.
if stat.IsDir() {
if err := os.MkdirAll(dp, 0777); err != nil {
return err
}
continue
}
if err := copyFile(sp, dp); err != nil {
return err
}
}
return nil
}
func copyFile(src, dest string) error {
data, err := ioutil.ReadFile(src)
if err != nil {
return err
}
err = ioutil.WriteFile(dest, data, 0644)
if err != nil {
return err
}
return nil
}
// readDirs reads the source directory recursively and
// returns relative paths to all files and empty directories.
func readDirs(src string) ([]string, error) {
var files []string
var err error
err = filepath.Walk(src, func(path string, f os.FileInfo, err error) error {
relativePath := strings.TrimPrefix(path, src)
if len(relativePath) > 0 {
files = append(files, relativePath)
}
return nil
})
if err != nil {
return nil, err
}
return files, nil
}
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// ReadDir returns the filenames in the given directory in sorted order.
func ReadDir(dirpath string) ([]string, error) {
dir, err := os.Open(dirpath)
if err != nil {
return nil, err
}
defer dir.Close()
names, err := dir.Readdirnames(-1)
if err != nil {
return nil, err
}
sort.Strings(names)
return names, nil
}
// Rename safely renames a file.
func Rename(from, to string) error {
if err := os.Rename(from, to); err != nil {
return err
}
// Directory was renamed; sync parent dir to persist rename.
pdir, err := OpenDir(filepath.Dir(to))
if err != nil {
return err
}
if err = Fsync(pdir); err != nil {
pdir.Close()
return err
}
return pdir.Close()
}
// Replace moves a file or directory to a new location and deletes any previous data.
// It is not atomic.
func Replace(from, to string) error {
if err := os.RemoveAll(to); err != nil {
return err
}
if err := os.Rename(from, to); err != nil {
return err
}
// Directory was renamed; sync parent dir to persist rename.
pdir, err := OpenDir(filepath.Dir(to))
if err != nil {
return err
}
if err = Fsync(pdir); err != nil {
pdir.Close()
return err
}
return pdir.Close()
}