1// Copyright 2015 The etcd Authors 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15package ioutil 16 17import ( 18 "io" 19 "os" 20 21 "github.com/coreos/etcd/pkg/fileutil" 22) 23 24// WriteAndSyncFile behaves just like ioutil.WriteFile in the standard library, 25// but calls Sync before closing the file. WriteAndSyncFile guarantees the data 26// is synced if there is no error returned. 27func WriteAndSyncFile(filename string, data []byte, perm os.FileMode) error { 28 f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm) 29 if err != nil { 30 return err 31 } 32 n, err := f.Write(data) 33 if err == nil && n < len(data) { 34 err = io.ErrShortWrite 35 } 36 if err == nil { 37 err = fileutil.Fsync(f) 38 } 39 if err1 := f.Close(); err == nil { 40 err = err1 41 } 42 return err 43} 44