Pin redis image version in docker compose file

[Bomme]

Currently we use the redis:alpine image tag which might resolve to a different image (with a "new" redis version on pull)
We should instead use a redis:<version>-alpine tag.
See the list of supported versions/tags

[Bomme]

@ffont could you let me know what version we should pin to match the one currently running in production?

[ffont]

Hi, in production we use an image called registry.sb.upf.edu/mtg/redis:6.2.5 which I suspect is redis 6.2.5, however, for some strange reason I can't find any code that generates this image so at this point I'm not sure why we're using this custom redis thing. To solve this issue you can pin to 6.2.5, but I'm a bit confused now as per why we're not using the standard redis image in production and whether we could switch to it. Do you remember anything about that @alastair?

[alastair]

The version of redis on the upf registry is exactly the same as the one on docker hub, we mirror it to prevent rate limit pull issues from docker hub.

Regarding the local version of redis - this is only used for development, and we don't have any volumes to save the database anyway. Because of this, I'm not too worried about the version unexpectedly being upgraded. If there was a data issue, this would be resolved by docker compose down (deleting the container) and docker compose up again.
I'm happy to pin it to some recent-ish version and leave it there. We only use very basic cache methods so I don't think it's even necessary to pin to exactly the same version as we have on prod

[Bomme]

Does this mean we now run version 7 aka latest?

I think it would still be helpful to pin or mark a version somehow somewhere to know what version of redis-py we should use.