dipc

Distributed Inter-Process Communication Library implemented in Python and Memcached. server

Using dipc

dipc library has two classes for distributed lock and semaphore, MemcacheLock and MemcacheSemaphore

Both of those clases has a first argument which is a list of memcached servers, name of lock/semaphore, ttl - timeout (in seconds). MemcacheSemaphore class has additional parameter value - which is number of processes that can access critical section.

acquire() method will wait forever until lock will be granted. You can specify argument blocking=False, and then will this methid will return True/False depending on if lock was granted or not.

>>> from dipc import MemcacheLock
... ml = MemcacheLock(["localhost:11211"], "lock", ttl=60)
... ml.acquire()
... # critical section
... ml.release()

>>> from dipc import MemcacheSemaphore
... ml = MemcacheSemaphore(["localhost:11211"], "semaphore", value=10, ttl=60)
... ml.acquire()
... # critical section
... ml.release()

There are also decorators available: distributed_lock and distributed_semaphore First argument is a list of hosts, but it also can be a function that returns list of hosts (for those environments that have config file read in a lazy manner)

>>> from dipc.decorators import distributed_lock
...
... @distributed_lock(["localhost:11211"], "lock", ttl=60)
... def foo():
...     # body

>>> from dipc.decorators import distributed_semaphore
...
... @distributed_semaphore(["localhost:11211"], "semaphore", value=10, ttl=60)
... def bar():
...     # body