feat: add redis and redis-cluster in limit-conn

[theweakgod]

Description

Fixes #10501 (#10501)

Add options for redis and redis-cluster in the limit-conn plugin, and use redis as the counter for the leaky bucket algorithm.

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[shreemaan-abhishek]

Let's bring support for limit-conn first then you can raise another PR for limit-req it's easier to review.

[theweakgod]

Let's bring support for limit-conn first then you can raise another PR for limit-req it's easier to review.

I'll split it into two pull requests. I encountered an issue during development related to the management of Redis keys. I noticed that APISIX generates a significant number of Redis keys. I'm considering consolidating these keys into a hash for better management. What are your thoughts on this?

[theweakgod]

@shreemaan-abhishek @monkeyDluffy6017 I have a problem now. I need to write a test case to test the plugin, but what address should I fill in for the redis cluster? How to fill in the cluster with password and the cluster without password? How to fill in the address of the redis singleton with password and without password?

[shreemaan-abhishek]

@theweakgod you will find redis servers (singleton and cluster) defined as docker compose applications in ci directory. You can use them or create new ones. You can also take inspiration from existing test cases for redis policy in limit count plugin.

[theweakgod]

@theweakgod you will find redis servers (singleton and cluster) defined as docker compose applications in ci directory. You can use them or create new ones. You can also take inspiration from existing test cases for redis policy in limit count plugin.

Ok.I see, thank u.

[theweakgod]

@shreemaan-abhishek @monkeyDluffy6017 I'm ready to review

[kayx23]

@shreemaan-abhishek I checked the doc and no more comments from me.