I have a Django 3.1.3 server that uses Redis for its cache via django-redis 4.12.1. I know that cache locks can generally be set via the following:
with cache.lock('my_cache_lock_key'):
# Execute some logic here, such as:
cache.set('some_key', 'Hello world', 3000)
Generally, the cache lock releases when the with
block completes execution. However, I have some custom logic in my code that sometimes does not release the cache lock (which is fine for my own reasons).
My question: is there a way to set a timeout value for Django cache locks, much in the same way as you can set timeouts for setting cache values (cache.set('some_key', 'Hello world', 3000)
)?
I've answered my own question. The following arguments are available for cache.lock()
:
def lock(
self,
key,
version=None,
timeout=None,
sleep=0.1,
blocking_timeout=None,
client=None,
thread_local=True,
):
Cross referencing that with comments from the Python Redis source, which uses the same arguments:
``timeout`` indicates a maximum life for the lock.
By default, it will remain locked until release() is called.
``timeout`` can be specified as a float or integer, both representing
the number of seconds to wait.
``sleep`` indicates the amount of time to sleep per loop iteration
when the lock is in blocking mode and another client is currently
holding the lock.
``blocking`` indicates whether calling ``acquire`` should block until
the lock has been acquired or to fail immediately, causing ``acquire``
to return False and the lock not being acquired. Defaults to True.
Note this value can be overridden by passing a ``blocking``
argument to ``acquire``.
``blocking_timeout`` indicates the maximum amount of time in seconds to
spend trying to acquire the lock. A value of ``None`` indicates
continue trying forever. ``blocking_timeout`` can be specified as a
float or integer, both representing the number of seconds to wait.
Therefore, to set the maximum time period of 2 seconds for which a cache lock takes effect, do something like this:
with cache.lock(key='my_cache_lock_key', timeout=2):
# Execute some logic here, such as:
cache.set('some_key', 'Hello world', 3000)