khodowany
57 lines
2.2 KiB
Python
57 lines
2.2 KiB
Python
"""Publish validated build directories with rollback on a failed replacement."""
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import contextlib
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import pathlib
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import shutil
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import tempfile
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def has_symlink(path):
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path = pathlib.Path(path).absolute()
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return any(parent.is_symlink() for parent in (path, *path.parents))
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@contextlib.contextmanager
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def publish_directories(replacements):
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pairs = [(pathlib.Path(source).absolute(), pathlib.Path(target).absolute()) for source, target in replacements]
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paths = [path for pair in pairs for path in pair]
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for path in paths:
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if has_symlink(path):
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raise ValueError(f'publication paths must not contain symlinks: {path}')
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pairs = [(source.resolve(), target.resolve()) for source, target in pairs]
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paths = [path for pair in pairs for path in pair]
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for index, path in enumerate(paths):
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if any(path == other or path.is_relative_to(other) or other.is_relative_to(path) for other in paths[:index]):
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raise ValueError('publication paths must not overlap')
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for source, target in pairs:
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if not source.is_dir() or (target.exists() and not target.is_dir()):
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raise ValueError('publication requires directories')
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target.parent.mkdir(parents=True, exist_ok=True)
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if source.stat().st_dev != target.parent.stat().st_dev:
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raise ValueError('publication must remain on the same filesystem')
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installed, backups, recovery = [], [], []
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try:
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for source, target in pairs:
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temporary = pathlib.Path(tempfile.mkdtemp(prefix='.publish_', dir=target.parent))
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recovery.append(temporary)
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if target.exists():
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backup = temporary / 'previous'
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target.rename(backup)
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backups.append((backup, target))
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source.rename(target)
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installed.append(target)
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yield
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except BaseException:
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try:
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for target in reversed(installed):
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if target.exists():
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shutil.rmtree(target)
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for backup, target in reversed(backups):
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backup.rename(target)
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except BaseException as error:
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raise RuntimeError(f'publication rollback failed; recovery directories retained: {recovery}') from error
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for temporary in recovery:
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shutil.rmtree(temporary)
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raise
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else:
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for temporary in recovery:
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shutil.rmtree(temporary)
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