| 42 | } |
| 43 | |
| 44 | func writeTempFileAtomicImp(fsi fsInterface, dirname string, data []byte) (filename string, err error) { |
| 45 | // write to a temp file to avoid race where two processes are writing at the same time. |
| 46 | tf, err2 := fsi.CreateTemp(dirname, "tmp") |
| 47 | if err2 != nil { |
| 48 | if os.IsNotExist(err2) { |
| 49 | if mdErr := fsi.MkdirAll(dirname, cache.DirMode); mdErr != nil { |
| 50 | return "", stderrors.Join(errors.Wrap(mdErr, "cannot create parent directory for temp file"), |
| 51 | errors.Wrap(err2, "cannot create temp file")) |
| 52 | } |
| 53 | |
| 54 | tf, err2 = fsi.CreateTemp(dirname, "tmp") |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | if err2 != nil { |
| 59 | return "", errors.Wrap(err2, "can't create tmp file") |
| 60 | } |
| 61 | |
| 62 | defer func() { |
| 63 | if cerr := tf.Close(); cerr != nil { |
| 64 | err = stderrors.Join(err, errors.Wrap(cerr, "can't close tmp file")) |
| 65 | } |
| 66 | |
| 67 | if err != nil { |
| 68 | // remove tmp file on error to avoid leaving them behind |
| 69 | if rerr := fsi.Remove(tf.Name()); rerr != nil { |
| 70 | err = stderrors.Join(err, errors.Wrap(rerr, "can't remove tmp file")) |
| 71 | } |
| 72 | |
| 73 | filename = "" |
| 74 | } |
| 75 | }() |
| 76 | |
| 77 | if _, err2 := tf.Write(data); err2 != nil { |
| 78 | return "", errors.Wrap(err2, "can't write to temp file") |
| 79 | } |
| 80 | |
| 81 | if err2 := tf.Sync(); err2 != nil { |
| 82 | return "", errors.Wrapf(err2, "cannot sync temporary file in dir %s", dirname) |
| 83 | } |
| 84 | |
| 85 | return tf.Name(), nil |
| 86 | } |