API

A platform independent file lock that supports the with-statement.

exception filelock.Timeout(lock_file)

Bases: OSError

Raised when the lock could not be acquired in timeout seconds.

lock_file

The path of the file lock.

class filelock.BaseFileLock(lock_file, timeout=- 1)

Bases: object

Implements the base class of a file lock.

property lock_file

The path to the lock file.

property timeout

You can set a default timeout for the filelock. It will be used as fallback value in the acquire method, if no timeout value (None) is given. If you want to disable the timeout, set it to a negative value. A timeout of 0 means, that there is exactly one attempt to acquire the file lock.

New in version 2.0.0.

property is_locked

True, if the object holds the file lock.

Changed in version 2.0.0: This was previously a method and is now a property.

acquire(timeout=None, poll_intervall=0.05)

Acquires the file lock or fails with a Timeout error.

# You can use this method in the context manager (recommended)
with lock.acquire():
    pass

# Or use an equivalent try-finally construct:
lock.acquire()
try:
    pass
finally:
    lock.release()

Parameters

• timeout (float) – The maximum time waited for the file lock. If timeout < 0, there is no timeout and this method will block until the lock could be acquired. If timeout is None, the default timeout is used.

• poll_intervall (float) – We check once in poll_intervall seconds if we can acquire the file lock.

Raises

Timeout – if the lock could not be acquired in timeout seconds.

Changed in version 2.0.0: This method returns now a proxy object instead of self, so that it can be used in a with statement without side effects.

release(force=False)

Releases the file lock.

Please note, that the lock is only completely released, if the lock counter is 0.

Also note, that the lock file itself is not automatically deleted.

Parameters

force (bool) – If true, the lock counter is ignored and the lock is released in every case.

class filelock.WindowsFileLock(lock_file, timeout=- 1)

Bases: BaseFileLock

Uses the msvcrt.locking() function to hard lock the lock file on windows systems.

class filelock.UnixFileLock(lock_file, timeout=- 1)

Bases: BaseFileLock

Uses the fcntl.flock() to hard lock the lock file on unix systems.

class filelock.SoftFileLock(lock_file, timeout=- 1)

Bases: BaseFileLock

Simply watches the existence of the lock file.

filelock.FileLock

alias of UnixFileLock

class filelock.AcquireReturnProxy(lock)

Bases: object