shreemaan-abhishek opened a new pull request, #13579:
URL: https://github.com/apache/apisix/pull/13579
### Description
The `limit-count` redis-cluster path executes the rate-limit script via
`evalsha` with a fallback to `eval` when the server returns `NOSCRIPT` (added
in #13363).
However, the bundled `resty-redis-cluster = 1.05-1` treats **any** command
error other than `MOVED`/`ASK`/`CLUSTERDOWN` (including `NOSCRIPT`) as a
possible node failure and triggers a full cluster slot refresh:
```lua
elseif string.sub(err, 1, 11) == "CLUSTERDOWN" then
return nil, "Cannot executing command, cluster status is failed!"
else
--There might be node fail, we should also refresh slot cache
self:refresh_slots() -- NOSCRIPT lands here
return nil, err
end
```
So in cluster mode every `NOSCRIPT` (first call on a fresh node, after
`SCRIPT FLUSH`, or after failover to a replica that does not yet have the
script cached) forces an unnecessary `refresh_slots()` over the whole cluster
before the `eval` fallback runs. The request still succeeds, but each cache
miss pays for a needless cluster-wide topology refresh.
`lua-resty-redis-cluster = 1.3.3-0` handles `NOSCRIPT` explicitly and
returns the error without refreshing slots, which matches the plugin's
`evalsha` fallback:
```lua
elseif string.sub(err, 1, 8) == "NOSCRIPT" then
return nil, err
```
This PR upgrades the dependency accordingly and adds a cluster test that
flushes the script cache and verifies the request still succeeds through the
`eval` fallback.
Note: APISIX already depends on the API7-maintained
`api7-lua-resty-redis-connector`, so adopting the maintained
`lua-resty-redis-cluster` fork (published on luarocks.org) is consistent with
existing dependencies.
### Checklist
- [x] I have explained the need for this PR and the problem it solves
- [x] I have explained the changes or the new features added to this PR
- [x] I have added tests corresponding to this change
- [ ] I have updated the documentation to reflect this change
- [x] I have verified that this change is backward compatible (if not,
please discuss on the [APISIX mailing
list](https://github.com/apache/apisix/tree/master#community) first)
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