feat: ai rate limiting redis support

[beardnick]

Description

Which issue(s) this PR fixes:

Fixes #12482

Notice

• I have updated the limit-count-redis.lua and limit-count-redis-cluster.lua files to ensure they now support rate-limiting during the log phase.
• I referred to the limit-conn-redis.lua file as a guide while implementing rate-limiting in the log phase.
• To ensure a clean testing environment, I added the require("lib.test_redis").flush_all() function to every Redis rate-limiting test case. Without this addition, the tests could fail unpredictably.
• I have adjusted the expected results in limit-req-redis.t and limit-req-redis-cluster.t test cases. After thorough verification, the correct behavior is [200, 403, 403, 403]. Previously, the results appeared as [403, 403, 403, 403] due to Redis not being properly cleaned beforehand.

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)

[beardnick]

@Baoyuantop PTAL

[membphis]

@beardnick many thx for your contribution, some CI tests are failed, you can fix them

[nic-6443]

Look like the changes in this PR should be limited to the ai-rate-limiting plugin and minor tweaks to the limit-count plugin. The current PR modifies too much code and test cases for other rate limiting plugins, expanding its scope. We should minimize unnecessary code changes.

[Baoyuantop]

Hi @beardnick, please check these comments.

[Baoyuantop]

Hi @beardnick, following up on the previous review comments. Please let us know if you have any updates. Thank you.

[Copilot]

Pull request overview

This PR extends the ai-rate-limiting plugin to support Redis / Redis Cluster backed counters (to share token quotas across APISIX replicas and persist across restarts), refactors the limit-count Redis backends to support log-phase token commits via timers, and updates docs/tests accordingly.

Changes:

• Add policy + Redis/Redis Cluster configuration to ai-rate-limiting and pass those settings through to limit-count.
• Refactor limit-count Redis implementations (single + cluster) and introduce a shared Lua-script utility.
• Add Redis / Redis Cluster coverage to ai-rate-limiting tests and document the new configuration options in EN/ZH docs.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
t/plugin/ai-rate-limiting.t	Adds test cases for ai-rate-limiting with policy=redis and policy=redis-cluster.
docs/en/latest/plugins/ai-rate-limiting.md	Documents Redis/Redis Cluster-backed quota sharing and new config fields.
docs/zh/latest/plugins/ai-rate-limiting.md	Same as EN docs, in Chinese.
apisix/plugins/limit-count/util.lua	New shared Redis EVAL script helpers for limit-count Redis backends.
apisix/plugins/limit-count/limit-count-redis.lua	Adds log-phase support via timers and uses the shared util script.
apisix/plugins/limit-count/limit-count-redis-cluster.lua	Same as single-Redis backend, for Redis Cluster.
apisix/plugins/ai-rate-limiting.lua	Adds schema fields for Redis policies and forwards Redis configuration into limit-count.

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[moonming]

Hi @beardnick, thank you for the AI rate limiting Redis support! This has received 26 reviews, showing significant community interest.

Since this has extensive review history:

1. Could you rebase on the latest master?
2. Please confirm all 26 review comments have been addressed
3. Provide a summary of the key design decisions made during the review process

The feature itself is important — token-based rate limiting for AI workloads needs a distributed backend like Redis. Looking forward to getting this across the finish line!

[Baoyuantop]

Hi @beardnick, for all the review comments above, please reply or mark them as resolved if you have already addressed them.

[Baoyuantop]

Hi @beardnick, I re-run CI, but some tests are still failing. Please fix it.

[beardnick]

Hi @beardnick, I re-run CI, but some tests are still failing. Please fix it.

The failed tests don't seem related to my PR.

[beardnick]

Hi @beardnick, thank you for the AI rate limiting Redis support! This has received 26 reviews, showing significant community interest.

Since this has extensive review history:

1. Could you rebase on the latest master?
2. Please confirm all 26 review comments have been addressed
3. Provide a summary of the key design decisions made during the review process

The feature itself is important — token-based rate limiting for AI workloads needs a distributed backend like Redis. Looking forward to getting this across the finish line!

1. I squashed my commits and rebased on master.
2. They are all addressed.
3. This PR updates the limit-count-redis plugin to support recording limits during the log phase. However, it will not add response headers as it does in the access phase.