How to achieve Redis queue per Drupal site?

igorl → changed the visibility of the branch 3353725-how-to-achieve to hidden.

That's a bug, even though it's prefixed with cache, other systems use the cache_prefix and so should queue. Add the RedisPrefixTrait trait and use the getPrefix() method it provides.

jan kellermann → made their first commit to this issue’s fork.

jan kellermann → changed the visibility of the branch 8.x-1.x to hidden.

Added prefix (and trait) to queues. Tested:

redis-cli KEYS *update_fetch_tasks:counter
1) "drupal:queue:update_fetch_tasks:counter"

redis-cli FLUSHALL

redis-cli KEYS *update_fetch_tasks:counter
1) "iFq2Dg:drupal:queue:update_fetch_tasks:counter"

Please review and feedback.

Reviewed and tested in customer project. Seems to solve the problem and works.

The fix looks good, my concern with this is that there is always a prefix even if not explicitly set, this means that all current queue items will become inaccessible with this change.

One fairly complex option would be an update function that loops over all queues, if they use the redis backend, we'd use https://redis.io/docs/latest/commands/rename/ to change it to the new prefix.

The current key prefix actually includes a hardcoded "drupal:" prefix. We could remove that, then people who were using this would have the choice to name their cache prefix just "drupal" and essentially match the current keys.

I have added another patch to allow an empty prefix so that the behavior is unchanged if the prefix is not set.
If a preset is set, it should also be applied. I doubt the sense of an update script to rename the keys, as it can lead to even more errors with shared hosting. A change request notice should be created here.

I've tested the patch and it works fine so far.