mirror of https://github.com/alerta/alerta.git
36 lines
1.1 KiB
Python
36 lines
1.1 KiB
Python
import contextlib
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import os
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@contextlib.contextmanager
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def mod_env(*remove, **update):
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"""
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See https://stackoverflow.com/questions/2059482#34333710
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Temporarily updates the ``os.environ`` dictionary in-place.
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The ``os.environ`` dictionary is updated in-place so that the modification
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is sure to work in all situations.
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:param remove: Environment variables to remove.
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:param update: Dictionary of environment variables and values to add/update.
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"""
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env = os.environ
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update = update or {}
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remove = remove or []
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# List of environment variables being updated or removed.
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stomped = (set(update.keys()) | set(remove)) & set(env.keys())
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# Environment variables and values to restore on exit.
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update_after = {k: env[k] for k in stomped}
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# Environment variables and values to remove on exit.
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remove_after = frozenset(k for k in update if k not in env)
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try:
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env.update(update)
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[env.pop(k, None) for k in remove]
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yield
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finally:
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env.update(update_after)
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[env.pop(k) for k in remove_after]
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