0001-utils-add-an-atomic_write-context-manager-32413.patch
passerelle/utils/files.py | ||
---|---|---|
1 |
# Copyright (C) 2018 Entr'ouvert |
|
2 |
# |
|
3 |
# This program is free software: you can redistribute it and/or modify it |
|
4 |
# under the terms of the GNU Affero General Public License as published |
|
5 |
# by the Free Software Foundation, either version 3 of the License, or |
|
6 |
# (at your option) any later version. |
|
7 |
# |
|
8 |
# This program is distributed in the hope that it will be useful, |
|
9 |
# but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
10 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
11 |
# GNU Affero General Public License for more details. |
|
12 |
# |
|
13 |
# You should have received a copy of the GNU Affero General Public License |
|
14 |
# along with this program. If not, see <http://www.gnu.org/licenses/>. |
|
15 | ||
16 |
import os.path |
|
17 |
import contextlib |
|
18 |
import tempfile |
|
19 | ||
20 | ||
21 |
@contextlib.contextmanager |
|
22 |
def atomic_write(filepath, **kwargs): |
|
23 |
'''Return a file descriptor to a temporary file using NamedTemporaryFile |
|
24 |
which will be atomically renamed to filepath if possible. |
|
25 | ||
26 |
Atomic renaming is only possible on the same filesystem, so the |
|
27 |
temporary file will be created in the same directory as the target file |
|
28 | ||
29 |
You can pass any possible argument to NamedTemporaryFile with kwargs. |
|
30 |
''' |
|
31 | ||
32 |
target_dir = kwargs.get('dir') or os.path.dirname(filepath) |
|
33 |
fd = tempfile.NamedTemporaryFile(dir=target_dir, delete=False) |
|
34 |
try: |
|
35 |
with fd: |
|
36 |
yield fd |
|
37 |
fd.flush() |
|
38 |
os.fsync(fd.fileno()) |
|
39 |
os.rename(fd.name, filepath) |
|
40 |
except Exception: |
|
41 |
os.unlink(fd.name) |
|
42 |
raise |
tests/test_utils_files.py | ||
---|---|---|
1 |
# Copyright (C) 2018 Entr'ouvert |
|
2 |
# |
|
3 |
# This program is free software: you can redistribute it and/or modify it |
|
4 |
# under the terms of the GNU Affero General Public License as published |
|
5 |
# by the Free Software Foundation, either version 3 of the License, or |
|
6 |
# (at your option) any later version. |
|
7 |
# |
|
8 |
# This program is distributed in the hope that it will be useful, |
|
9 |
# but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
10 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
11 |
# GNU Affero General Public License for more details. |
|
12 |
# |
|
13 |
# You should have received a copy of the GNU Affero General Public License |
|
14 |
# along with this program. If not, see <http://www.gnu.org/licenses/>. |
|
15 | ||
16 |
import os |
|
17 | ||
18 |
import pytest |
|
19 | ||
20 |
from passerelle.utils.files import atomic_write |
|
21 | ||
22 | ||
23 |
def test_atomic_write(tmpdir): |
|
24 |
filepath = str(tmpdir.join('test')) |
|
25 | ||
26 |
with pytest.raises(Exception): |
|
27 |
with atomic_write(filepath) as fd: |
|
28 |
fd.write('coucou') |
|
29 |
raise Exception() |
|
30 |
assert not os.path.exists(filepath) |
|
31 |
assert os.listdir(str(tmpdir)) == [] |
|
32 | ||
33 |
with atomic_write(filepath) as fd: |
|
34 |
fd.write('coucou') |
|
35 | ||
36 |
assert os.path.exists(filepath) |
|
37 |
with open(filepath) as fd: |
|
38 |
assert fd.read() == 'coucou' |
|
0 |
- |