78 lines
2.1 KiB
Python
78 lines
2.1 KiB
Python
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# coding=utf-8
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"""
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@project: MaxKB
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@Author：虎
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@file： file_lock.py
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@date：2024/8/20 10:48
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@desc:
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"""
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import errno
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import hashlib
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import os
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import time
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import six
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from common.lock.base_lock import BaseLock
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from smartdoc.const import PROJECT_DIR
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def key_to_lock_name(key):
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"""
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Combine part of a key with its hash to prevent very long filenames
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"""
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MAX_LENGTH = 50
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key_hash = hashlib.md5(six.b(key)).hexdigest()
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lock_name = key[:MAX_LENGTH - len(key_hash) - 1] + '_' + key_hash
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return lock_name
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class FileLock(BaseLock):
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"""
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File locking backend.
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"""
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def __init__(self, settings=None):
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if settings is None:
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settings = {}
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self.location = settings.get('location')
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if self.location is None:
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self.location = os.path.join(PROJECT_DIR, 'data', 'lock')
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try:
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os.makedirs(self.location)
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except OSError as error:
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# Directory exists?
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if error.errno != errno.EEXIST:
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# Re-raise unexpected OSError
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raise
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def _get_lock_path(self, key):
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lock_name = key_to_lock_name(key)
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return os.path.join(self.location, lock_name)
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def try_lock(self, key, timeout):
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lock_path = self._get_lock_path(key)
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try:
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# 创建锁文件,如果没创建成功则拿不到
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fd = os.open(lock_path, os.O_CREAT | os.O_EXCL)
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except OSError as error:
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if error.errno == errno.EEXIST:
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# File already exists, check its modification time
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mtime = os.path.getmtime(lock_path)
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ttl = mtime + timeout - time.time()
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if ttl > 0:
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return False
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else:
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# 如果超时时间已到,直接上锁成功继续执行
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os.utime(lock_path, None)
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return True
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else:
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return False
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else:
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os.close(fd)
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return True
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def un_lock(self, key):
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lock_path = self._get_lock_path(key)
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os.remove(lock_path)
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