locks

POSIX file system locking using flock.

Getting started

Install this package with

pip install locks

Usage

The simplest usage is to block indefinitely until the lock is acquired

from locks import Mutex

with Mutex('/tmp/file.lock'):
    # do exclusive stuff here

Alternatively, block until a timeout is reached

from locks import Mutex

try:
    with Mutex('/tmp/file.lock', timeout=0.5):
        # do exclusive stuff here
except BlockingIOError:
    # handle the failure to acquire the lock

Finally, a common paradigm is to attempt to acquire the lock without blocking, do something, and then block indefinitely. Here callback will be called once if we cannot immediately acquire the lock, and then we will block indefinitely.

def callback():
    print("Blocking: waiting for file lock on '/tmp/file.lock'")

with Mutex('/tmp/file.lock', callback=callback):
    # do exclusive stuff here

If both callback and timeout are used then we will attempt to acquire the lock until the timeout is reached, and then we will block indefinitely.

License

This project is licensed under the MIT License. See the LICENSE file.