Fixes jazzband#691 - Obsolete THUMBNAIL_KVSTORE

CHANGES.rst

@@ -2,6 +2,10 @@
 Changes
 =======
 
+Unreleased
+==========
+* Deprecated ``THUMBNAIL_KVSTORE``. Only the Django cache-based store will be
+  used in a future version.
 * Add support for Django 5.0 and 5.1
 * Drop support for Django 3.2, 4.0 and 4.1
 

docs/reference/settings.rst

@@ -31,13 +31,20 @@ your own implementation.
 
 - Default: ``'sorl.thumbnail.kvstores.cached_db_kvstore.KVStore'``
 
+.. deprecated:: 12.11.0
+
+    Using any other KVStore than the Cached Db KVStore is deprecated.
+    Please configure the cache that suits your use case at Django level and set
+    this cache alias in ``THUMBNAIL_CACHE``.
+
 sorl-thumbnail needs a Key Value Store to :doc:`/operation`.
 sorl-thumbnail ships with support for three Key Value Stores:
 
 Cached DB
 ---------
 ``sorl.thumbnail.kvstores.cached_db_kvstore.KVStore``. This is the default and
-preferred Key Value Store.
+preferred Key Value Store. It uses the cache configured at the Django project
+level.
 
 Features
 ^^^^^^^^
@@ -50,6 +57,11 @@ Features
 
 Redis
 -----
+From Django 4.0, you can configure a Redis cache at Django level and then use
+the Cached DB store while using the configured cache alias in the
+``THUMBNAIL_CACHE`` setting. Therefore the Redis store in sorl-thumbnail and its
+associated ``THUMBNAIL_REDIS*`` settings maybe removed in the future.
+
 ``sorl.thumbnail.kvstores.redis_kvstore.KVStore``. It requires you to install a
 Redis server as well as a `redis python client
 <https://github.com/andymccurdy/redis-py/>`_.
@@ -241,8 +253,11 @@ Only applicable for the Cached DB Key Value Store.
 
 - Default: ``'default'``
 
-Cache configuration for Cached DB Key Value Store. Defaults to the ``'default'`` cache
-but some applications might have multiple cache clusters.
+Django configured cache alias to use for Cached DB Key Value Store. Defaults to
+the ``'default'`` cache but you can use any other cache configured in the Django
+project.
+
+- ``https://docs.djangoproject.com/en/stable/topics/cache/``
 
 
 ``THUMBNAIL_KEY_PREFIX``

docs/requirements.rst

@@ -18,10 +18,13 @@ a **cached database** which requires no special installation to your normal
 Django setup besides installing a proper cache like memcached **or** you can
 setup **redis** which requires a little bit more work.
 
+Since Django 4.0, the Redis cache can be configured at Django level, so any
+alternative Key Value Store in sorl-thumbnail is now deprecated.
+
 Cached DB
 ---------
 All you need to use the cached database key value store is a database and `cache
-<https://docs.djangoproject.com/en/dev/topics/cache/>`_ setup properly using
+<https://docs.djangoproject.com/en/stable/topics/cache/>`_ setup properly using
 memcached. This cache needs to be really fast so **using anything else than
 memcached is not recommended**.
 

sorl/thumbnail/kvstores/base.py

@@ -1,3 +1,5 @@
+import warnings
+
 from sorl.thumbnail.conf import settings
 from sorl.thumbnail.helpers import ThumbnailError, deserialize, serialize
 from sorl.thumbnail.images import deserialize_image_file, serialize_image_file
@@ -18,6 +20,15 @@ def del_prefix(key):
 
 
 class KVStoreBase:
+    def __init__(self):
+        if not getattr(self, '_cached_db_kvstore', False):
+            warnings.warn(
+                "Using any other KVStore than Cached Db KVStore is deprecated. "
+                "Please configure the cache that suits your use case at Django "
+                "level and set this cache alias in THUMBNAIL_CACHE.",
+                DeprecationWarning
+            )
+
     def get(self, image_file):
         """
         Gets the ``image_file`` from store. Returns ``None`` if not found.

sorl/thumbnail/kvstores/cached_db_kvstore.py

@@ -10,8 +10,7 @@ class EMPTY_VALUE:
 
 
 class KVStore(KVStoreBase):
-    def __init__(self):
-        super().__init__()
+    _cached_db_kvstore = True
 
     @property
     def cache(self):