django-cache-lock

A simple lock extension for django's cache to prevent concurrent editing.

Installation

Install django-cache-lock by using pip

pip install django-cache-lock

Quick Start

You can work with django-cache-lock by using with-statement or decorator.

from django_lock import lock

with lock("global"):
    pass

@lock("global")
def foo():
    pass

A shortcut to lock model instance

from django.db import models
from django_lock import model_lock

class Foo(models.Model):
    bar = models.CharField(max_length=8)

    @lock_model
    def lock_pk(self):
        pass

    @lock_model("bar", blocking=False)
    def lock_bar(self):
        pass

    def nolock(self):
        pass

foo = Foo()
with lock_model(foo, blocking=False):
    nolock()

Configurations

key	default	desc
DJANGOLOCK_PREFIX	"lock:"	lock's key prefix stored in cache
DJANGOLOCK_SLEEP	0.1	default interval time to acquire a lock if a lock is holded by others
DJANGOLOCK_RELEASEONDEL	True	release lock when __del__ is called if True

Advanced usage

For more usages, please read the code.

Supported backends

• django.core.cache.backends.db
• django.core.cache.backends.file
• django.core.cache.backends.locmem
• django.core.cache.backends.memcached
• django-redis
• django-redis-cache

ATTENTIONS

locmem backend

• DO NOT USE locmem backend in a product environment.

memcached backend

• Memcached does not support milliseconds expire time, and its' expire time is not very exact. So memcached lock's timeout time is not as exact as other backends.

redis backend

• We didn't test distributed redis lock.

TODOS:

• use memcached's cas to release lock
• reacquire and extend lock
• database backend cache support