好吧，所以我最终用我在这里写的代码，在我的网站上链接是死的，在archive.org上查看(也可在GitHub上)。我可以以以下方式使用它:

from filelock import FileLock

with FileLock("myfile.txt"):
    # work with the file as it is now locked
    print("Lock acquired.")

锁定是平台和设备特定的，但一般来说，你有几个选择:

Use flock(), or equivalent (if your os supports it). This is advisory locking, unless you check for the lock, it's ignored. Use a lock-copy-move-unlock methodology, where you copy the file, write the new data, then move it (move, not copy - move is an atomic operation in Linux -- check your OS), and you check for the existence of the lock file. Use a directory as a "lock". This is necessary if you're writing to NFS, since NFS doesn't support flock(). There's also the possibility of using shared memory between the processes, but I've never tried that; it's very OS-specific.

对于所有这些方法，您必须使用自旋锁(失败后重试)技术来获取和测试锁。这确实为错误同步留下了一个小窗口，但它通常小到不会成为一个大问题。

如果您正在寻找跨平台的解决方案，那么您最好通过其他机制将日志记录到另一个系统(其次是上面的NFS技术)。

请注意，sqlite在NFS上受到与普通文件相同的约束，因此您不能在网络共享上写入sqlite数据库并免费获得同步。

下面是一个如何使用filelock库的例子，它类似于Evan Fossmark的实现:

from filelock import FileLock

lockfile = r"c:\scr.txt"
lock = FileLock(lockfile + ".lock")
with lock:
    file = open(path, "w")
    file.write("123")
    file.close()

with lock:块中的任何代码都是线程安全的，这意味着它将在另一个进程访问该文件之前完成。

场景是这样的: 用户请求一个文件执行某些操作。然后，如果用户再次发送相同的请求，它会通知用户在第一个请求完成之前不会完成第二个请求。这就是为什么我使用锁定机制来处理这个问题。

下面是我的工作代码:

from lockfile import LockFile
lock = LockFile(lock_file_path)
status = ""
if not lock.is_locked():
    lock.acquire()
    status = lock.path + ' is locked.'
    print status
else:
    status = lock.path + " is already locked."
    print status

return status

其他解决方案引用了大量的外部代码库。如果您更愿意自己动手，这里有一些跨平台解决方案的代码，在Linux / DOS系统上使用各自的文件锁定工具。

try:
    # Posix based file locking (Linux, Ubuntu, MacOS, etc.)
    #   Only allows locking on writable files, might cause
    #   strange results for reading.
    import fcntl, os
    def lock_file(f):
        if f.writable(): fcntl.lockf(f, fcntl.LOCK_EX)
    def unlock_file(f):
        if f.writable(): fcntl.lockf(f, fcntl.LOCK_UN)
except ModuleNotFoundError:
    # Windows file locking
    import msvcrt, os
    def file_size(f):
        return os.path.getsize( os.path.realpath(f.name) )
    def lock_file(f):
        msvcrt.locking(f.fileno(), msvcrt.LK_RLCK, file_size(f))
    def unlock_file(f):
        msvcrt.locking(f.fileno(), msvcrt.LK_UNLCK, file_size(f))


# Class for ensuring that all file operations are atomic, treat
# initialization like a standard call to 'open' that happens to be atomic.
# This file opener *must* be used in a "with" block.
class AtomicOpen:
    # Open the file with arguments provided by user. Then acquire
    # a lock on that file object (WARNING: Advisory locking).
    def __init__(self, path, *args, **kwargs):
        # Open the file and acquire a lock on the file before operating
        self.file = open(path,*args, **kwargs)
        # Lock the opened file
        lock_file(self.file)

    # Return the opened file object (knowing a lock has been obtained).
    def __enter__(self, *args, **kwargs): return self.file

    # Unlock the file and close the file object.
    def __exit__(self, exc_type=None, exc_value=None, traceback=None):        
        # Flush to make sure all buffered contents are written to file.
        self.file.flush()
        os.fsync(self.file.fileno())
        # Release the lock on the file.
        unlock_file(self.file)
        self.file.close()
        # Handle exceptions that may have come up during execution, by
        # default any exceptions are raised to the user.
        if (exc_type != None): return False
        else:                  return True        

现在，AtomicOpen可以在with块中使用，而在这里通常使用open语句。

警告:

如果在Windows上运行并且Python在调用exit之前崩溃，我不确定锁的行为是什么。 这里提供的锁定是建议的，而不是绝对的。所有潜在的竞争进程必须使用“AtomicOpen”类。 截至2020年11月9日，此代码仅锁定Posix系统上的可写文件。在发布之后的某一时刻，在此日期之前，使用fcntl是非法的。锁定只读文件。

在操作系统级别协调对单个文件的访问充满了您可能不想解决的各种问题。

最好的办法是有一个单独的进程来协调对该文件的读写访问。