Mercurial > hg > AtomicWrite
comparison atomic/writer.py @ 1:a4188f41ca35 default tip
basically the thing
| author | Jeff Hammel <k0scist@gmail.com> |
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| date | Fri, 02 Jan 2015 13:22:09 -0800 |
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| children |
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| 0:dc90512b9c98 | 1:a4188f41ca35 |
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| 1 # -*- coding: utf-8 -*- | |
| 2 | |
| 3 """ | |
| 4 write a file atomically | |
| 5 """ | |
| 6 | |
| 7 # imports | |
| 8 import os | |
| 9 import shutil | |
| 10 import tempfile | |
| 11 | |
| 12 # module globals | |
| 13 __all__ = ['ensure_dir', 'write'] | |
| 14 | |
| 15 def ensure_dir(directory): | |
| 16 """ensure a directory exists""" | |
| 17 if os.path.exists(directory): | |
| 18 if not os.path.isdir(directory): | |
| 19 raise OSError("Not a directory: '{}'".format(directory)) | |
| 20 return directory | |
| 21 os.makedirs(directory) | |
| 22 return directory | |
| 23 | |
| 24 | |
| 25 def write(contents, path): | |
| 26 """atomically write a file taking advantage of move""" | |
| 27 | |
| 28 path = os.path.abspath(path) | |
| 29 fd, tmp_path = tempfile.mkstemp() | |
| 30 os.write(fd, contents) | |
| 31 os.close(fd) | |
| 32 ensure_dir(os.path.dirname(path)) | |
| 33 shutil.move(tmp_path, path) |