util.py

@contextmanager
def exploding_redis_mutex(key, timeout=10):
    r = redis.Redis(host=settings.REDIS_HOST, port=settings.REDIS_PORT, db=settings.REDIS_DB)
    mutex_key = ('mutex', key)
    while not r.setnx(mutex_key, datetime.now()):
        val = datetime.strptime(r.get(mutex_key), '%Y-%m-%d %H:%M:%S.%f')
        if (datetime.now() - val).seconds > timeout:
            r.delete(mutex_key)
        else:
            raise RedisMutexLockedError("'%s' is already locked in the mutex" % (key,))
    try:
        yield True
    finally:
        r.delete(mutex_key)
        del(r)