Cache OPTIONS are not passed to the Redis client.

[Ben Picolo]

Hello! First Django interaction, so please let me know how better I can give info here.

I discovered unintentionally that there's no default socket_timeout set for Redis cache connections. This is an issue on it's own (unsafe default that's a particularly hard issue to track down), but in trying to set those timeouts, I hit some tough edges of documentation/usage.

The cache documentation says that the OPTIONS object is passed to the third-party connection class for connections backed by third-party libraries ​for connections backed by third-party libraries. This is reaffirmed for the redis cache specifically ​here.

Right now, though, these OPTIONS are passed to the ​first-party RedisCacheClient object, so you can't pass in options expected by the redis connection pool ​link. In that sense, RedisCacheClient is being treated as a "first-party" cache according to these docs, but it defers directly to the redis library.

One could do a variety of subclassing to make this work, but there's quite a few layers of indirection here, so it's hard to identify exactly what one should subclass in order to get arguments to the connection class appropriately.

(For now, my workaround is take advantage of the from_url behavior where the connection class ​pulls arguments out of the connection query string, but this isn't straightforward and feels brittle to django implementation details).

There are a couple of options here – revising documentation or changing behavior (or both).

In my ideal case, it would be great for it to be easy to pass down explicit socket and other timeouts. To me, that suggests updating behavior is ideal, because the documentation would potentially lead folk down a path of tough to navigate behavior. Passing those options in tact, or updating the RedisCacheClient to have a wider range of available options would both work out.

[Mariusz Felisiak]

Thanks for the report. Agreed, we should pass all options to the Redis client. Would you like to prepare a patch? It's probably enough to pass the OPTIONS to the underlying client, e.g.

django/core/cache/backends/redis.py

@@ -35 +35 @@
         db=None,
         pool_class=None,
         parser_class=None,
+        **options,
     ):
         import redis
 
@@ -58 +59 @@
             parser_class = import_string(parser_class)
         parser_class = parser_class or self._lib.connection.DefaultParser
 
+        self._options = options
         self._pool_options = {"parser_class": parser_class, "db": db}
 
     def _get_connection_pool_index(self, write):
@@ -81 +83 @@
         # cache client can be implemented which might require the key to select
         # the server, e.g. sharding.
         pool = self._get_connection_pool(write)
-        return self._client(connection_pool=pool)
+        return self._client(connection_pool=pool, **self._options)
 
     def add(self, key, value, timeout):
         client = self.get_client(key, write=True)

Marking as a release blocker as this is as a bug in the new feature.

[Ben Picolo]

I could probably give that a go, will see if I can take it on this weekend

[Mariusz Felisiak]

Replying to Ben Picolo:

I could probably give that a go, will see if I can take it on this weekend

Sounds good!

[Mariusz Felisiak]

​PR

[GitHub <noreply@…>]

In d27e6b23:

Fixed #33681 -- Made Redis client pass CACHESOPTIONS to a connection pool.

Thanks Ben Picolo for the report.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 5c6ebe19:

[4.0.x] Fixed #33681 -- Made Redis client pass CACHESOPTIONS to a connection pool.

Thanks Ben Picolo for the report.
Backport of d27e6b233f83c3429f21ff3c250a28ff302637ef from main