Flockcontext

Improves fcntl.flock usage.

flock is a Unix command for file locking, the mecanism that controls access restrictions of files.

Usage

Exclusive blocking lock:

from flockcontext import FlockOpen

with FlockOpen('/tmp/my.lock', 'w') as lock:
    lock.fd.write('Locked\n')

Exclusive blocking lock with 1 second timeout:

from flockcontext import FlockOpen

with FlockOpen('/tmp/my.lock', 'w', timeout=1) as lock:
    lock.fd.write('Locked\n')

Exclusive non-blocking lock:

from flockcontext import FlockOpen

try:
    with FlockOpen('/tmp/my.lock', 'w', blocking=False) as lock:
        lock.fd.write('Locked\n')
except IOError as e:
    print('Can not acquire lock')

Shared blocking lock:

from flockcontext import Flock

with FlockOpen('/tmp/my.lock', 'w', exclusive=False) as lock:
    lock.fd.write('Locked\n')

Acquire and release within context:

from flockcontext import FlockOpen

with FlockOpen('/tmp/my.lock', 'w') as lock:
    print('Lock acquired')
    lock.fd.write('Locked\n')

    lock.release()
    print('Lock released')

    lock.acquire()
    print('Lock acquired')
    lock.fd.write('Locked\n')

Locking already opened file:

from flockcontext import Flock

with open('/tmp/my.lock', 'w') as fd:
    with Flock(fd):
        fd.write('Locked\n')

License

• Free software: BSD license