Tipragot
628be439b8
Cela permet de ne pas avoir de problèmes de compatibilité car python est dans le git.
170 lines
4.7 KiB
Python
170 lines
4.7 KiB
Python
"""holds locking functionality that works across processes."""
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from __future__ import annotations
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import logging
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import os
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from abc import ABCMeta, abstractmethod
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from contextlib import contextmanager, suppress
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from pathlib import Path
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from threading import Lock, RLock
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from filelock import FileLock, Timeout
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class _CountedFileLock(FileLock):
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def __init__(self, lock_file) -> None:
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parent = os.path.dirname(lock_file)
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if not os.path.isdir(parent):
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with suppress(OSError):
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os.makedirs(parent)
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super().__init__(lock_file)
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self.count = 0
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self.thread_safe = RLock()
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def acquire(self, timeout=None, poll_interval=0.05):
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if not self.thread_safe.acquire(timeout=-1 if timeout is None else timeout):
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raise Timeout(self.lock_file)
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if self.count == 0:
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super().acquire(timeout, poll_interval)
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self.count += 1
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def release(self, force=False): # noqa: FBT002
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with self.thread_safe:
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if self.count > 0:
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self.thread_safe.release()
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if self.count == 1:
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super().release(force=force)
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self.count = max(self.count - 1, 0)
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_lock_store = {}
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_store_lock = Lock()
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class PathLockBase(metaclass=ABCMeta):
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def __init__(self, folder) -> None:
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path = Path(folder)
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self.path = path.resolve() if path.exists() else path
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def __repr__(self) -> str:
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return f"{self.__class__.__name__}({self.path})"
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def __div__(self, other):
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return type(self)(self.path / other)
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def __truediv__(self, other):
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return self.__div__(other)
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@abstractmethod
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def __enter__(self):
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raise NotImplementedError
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@abstractmethod
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def __exit__(self, exc_type, exc_val, exc_tb):
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raise NotImplementedError
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@abstractmethod
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@contextmanager
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def lock_for_key(self, name, no_block=False): # noqa: FBT002
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raise NotImplementedError
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@abstractmethod
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@contextmanager
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def non_reentrant_lock_for_key(self, name):
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raise NotImplementedError
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class ReentrantFileLock(PathLockBase):
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def __init__(self, folder) -> None:
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super().__init__(folder)
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self._lock = None
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def _create_lock(self, name=""):
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lock_file = str(self.path / f"{name}.lock")
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with _store_lock:
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if lock_file not in _lock_store:
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_lock_store[lock_file] = _CountedFileLock(lock_file)
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return _lock_store[lock_file]
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@staticmethod
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def _del_lock(lock):
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if lock is not None:
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with _store_lock, lock.thread_safe:
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if lock.count == 0:
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_lock_store.pop(lock.lock_file, None)
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def __del__(self) -> None:
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self._del_lock(self._lock)
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def __enter__(self):
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self._lock = self._create_lock()
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self._lock_file(self._lock)
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def __exit__(self, exc_type, exc_val, exc_tb):
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self._release(self._lock)
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self._del_lock(self._lock)
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self._lock = None
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def _lock_file(self, lock, no_block=False): # noqa: FBT002
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# multiple processes might be trying to get a first lock... so we cannot check if this directory exist without
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# a lock, but that lock might then become expensive, and it's not clear where that lock should live.
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# Instead here we just ignore if we fail to create the directory.
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with suppress(OSError):
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os.makedirs(str(self.path))
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try:
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lock.acquire(0.0001)
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except Timeout:
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if no_block:
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raise
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logging.debug("lock file %s present, will block until released", lock.lock_file)
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lock.release() # release the acquire try from above
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lock.acquire()
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@staticmethod
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def _release(lock):
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lock.release()
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@contextmanager
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def lock_for_key(self, name, no_block=False): # noqa: FBT002
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lock = self._create_lock(name)
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try:
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try:
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self._lock_file(lock, no_block)
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yield
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finally:
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self._release(lock)
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finally:
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self._del_lock(lock)
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lock = None
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@contextmanager
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def non_reentrant_lock_for_key(self, name):
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with _CountedFileLock(str(self.path / f"{name}.lock")):
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yield
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class NoOpFileLock(PathLockBase):
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def __enter__(self):
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raise NotImplementedError
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def __exit__(self, exc_type, exc_val, exc_tb):
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raise NotImplementedError
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@contextmanager
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def lock_for_key(self, name, no_block=False): # noqa: ARG002, FBT002
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yield
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@contextmanager
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def non_reentrant_lock_for_key(self, name): # noqa: ARG002
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yield
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__all__ = [
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"NoOpFileLock",
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"ReentrantFileLock",
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"Timeout",
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]
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