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1 # -*- coding: utf-8 -*-
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2
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3 """
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4 write a file atomically
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5 """
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6
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7 # imports
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8 import os
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9 import shutil
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10 import tempfile
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11
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12 # module globals
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13 __all__ = ['ensure_dir', 'write']
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14
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15 def ensure_dir(directory):
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16 """ensure a directory exists"""
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17 if os.path.exists(directory):
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18 if not os.path.isdir(directory):
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19 raise OSError("Not a directory: '{}'".format(directory))
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20 return directory
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21 os.makedirs(directory)
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22 return directory
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23
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24
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25 def write(contents, path):
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26 """atomically write a file taking advantage of move"""
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27
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28 path = os.path.abspath(path)
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29 fd, tmp_path = tempfile.mkstemp()
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30 os.write(fd, contents)
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31 os.close(fd)
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32 ensure_dir(os.path.dirname(path))
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33 shutil.move(tmp_path, path)
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