add publishing to core

[yisraelU]

closes #1049

• This is a big change, which breaks binary compatibility, as it moves publishing and pubsub stats out of the streams module into the effects module.

Background - Redis has a pubsub feature that when activated changes the Connection from a standard connection to a "PubSub" connection. A "PubSub" connection cannot run standard Redis commands nor does it obey the RESP semantics of Req->Reply. To this end Publishing and Stats were implemented in a separate module.

Problem - This is too limiting as , publishing itself (not subscribe) and stats are standard Redis commands and should be accessible within the standard Redis Connection.

Solution - This pr creates moves the abstract publish and stats traits to the effects module and provides a standard implementation. The pubsub feature available in the streaming module , makes use of that implementation too

[mmienko]

I think it might make sense for the pubsub api to depend on RedisCommands, rather than have an intermediate LivePubSubStats abstraction. The streams impl already does that, see here.

[yisraelU]

RedisCommands would give access to all Redis commands , which is unsafe for a pubsub connection as once the connection is in "Subscribe" mode , redis will not respect the standard RESP

[mmienko]

True, and this is also the same for the streams, which provides a nice fs2 abstraction over the commands. It doesn’t call those extra commands. However, subscribe is different as it changes the connection state, whereas xread can be used on connection sharing the other commands.

[mmienko]

Wondering if a single trait is fine here, though I like the break out of stats since Redis namespaces the stats with "pubsub" which is different the the publish commands

[yisraelU]

Redis puts publish under pubsub too https://redis.io/docs/latest/commands/publish/ , hence I grouped it together , but I'm ok with either way

[mmienko]

Yea it’s fine, was more so curious your thoughts

[mmienko]

Might be cleaner/safer to share a deferred/queue between the main fiber and subscribing fiber

[yisraelU]

@Mergifyio rebase!

[mergify]

rebase !

❌ Base branch update has failed

Details

Git reported the following error:

Rebasing (1/7)
Auto-merging modules/effects/src/main/scala/dev/profunktor/redis4cats/commands.scala
Auto-merging modules/effects/src/main/scala/dev/profunktor/redis4cats/redis.scala
Auto-merging modules/tests/src/test/scala/dev/profunktor/redis4cats/Redis4CatsFunSuite.scala
CONFLICT (content): Merge conflict in modules/tests/src/test/scala/dev/profunktor/redis4cats/Redis4CatsFunSuite.scala
Auto-merging site/docs/effects/index.md
error: could not apply a6465ff... add publishing to core
hint: Resolve all conflicts manually, mark them as resolved with
hint: "git add/rm <conflicted_files>", then run "git rebase --continue".
hint: You can instead skip this commit: run "git rebase --skip".
hint: To abort and get back to the state before "git rebase", run "git rebase --abort".
Could not apply a6465ff... add publishing to core

[yisraelU]

@Mergifyio rebase!

[mergify]

rebase !

✅ Branch has been successfully rebased