Redis 6 support

[omnibs]

Hi! Thank you for writing Hedis =]

I noticed the readme says:

Hedis is intended to be used with the latest stable version of Redis (currently 5.0).

Is the readme merely outdated, or is 6.0 indeed not supported yet?

[michaelglass]

from https://raw.githubusercontent.com/antirez/redis/6.0/00-RELEASENOTES

Migrating from 5.0 to 6.0
=========================

Redis 6.0 is mostly a strict superset of 5.0, you should not have any problem
upgrading your application from 5.0 to 6.0. However this is a list of small
non-backward compatible changes introduced in the 6.0 release:

* The SPOP <count> command no longer returns null when the set key does not
  exist. Now it returns the empty set as it should and as happens when it is
  called with a 0 argument. This is technically a fix, however it changes the
  old behavior.

I'm guessing we can test out redis 6 compatibility and report back?

see: master...NoRedInk:test-redis-6

[michaelglass]

looks like tests on master here are already broken so it'll be a little tricky to test.

[k-bx]

PRs fixing all of these are very much welcome!

Tests worked for me locally last time I've checked, so it was only Travis that needed some love. Anyways, open for contributions, but don't have a lot of time for this ATM myself, unfortunately.

[michaelglass]

@k-bx you are the best. We're now running a big piece of our prod hedis load against 6.x. Will make a little PR and hopefully also figure out what's up with travis. Thank you!

[michaelglass]

preliminary info:
we upgraded our redis cluster from 5.0.6 to 6.0.4

• all existing applications were happy / stayed online / continued to talk to redis
• new apps failed during boot (??!!). will probably debug further

So maybe there's support for a single redis instance but not cluster yet? I couldn't see significant cluster changes in the changelog so a little confusing

[k-bx]

Cluster support was added in #157 , please see if that's what you're looking for

[michaelglass]

Yup! Our team (mostly jasper) wrapped up that cluster work, but we only tested against Redis 5.0 in cluster mode. Upgrading to Redis 6 in cluster mode caused some strange errors we'll try to debug.

[k-bx]

Ah, gotcha! Thanks

[aravindgopall]

@michaelglass is this still the case. we have successfully tested with juspay fork for Redis 6.

[michaelglass]

@aravindgopall sorry I'm not on the project anymore. Happy to hear it's working for you.

[omnibs]

@aravindgopall thank you so much for reporting, i'll give it a try!

[qnikst]

Please see MR #211 it provides redis 7 support for all existing functions. It does not provide support for newly added functions. Unfortunately I see no way to make the change backward compatible, my company adopted those changes, but I would love to see if anyone would give that a try before merging into the master.

[qnikst]

@aravindgopall, sorry for asking you here, but I wonder if Juspay want to contribute efforts upstream, otherwise be may get into a situations here the codebases would significally diverge making it impossible to combine features that appear in the projects.