feat(redis): add Redis Sentinel support for HA cache discovery

[ex0a]

• Add build_sentinel() function to discover Redis master via Sentinel
• Parse redis-sentinel://host:port,host2:port2/master_name URLs
• Query sentinels with SENTINEL GET-MASTER-ADDR-BY-NAME
• Add comprehensive logging for debugging discovery issues
• Support password auth and optional DB selection
• Route sentinel URLs from endpoint config path in cache.rs

[sylvestre]

sorry, it conflicts

[ex0a]

What would you suggest? I'm using this personally but thought it might help someone else

[AJIOB]

Hi @ex0a ,

You should rebase your changes to the latest master branch changes or just merge them to your branch - and resolve the conflicts.

Then you need to push your changes to your branch.

That's should be fine!

[AJIOB]

CC @Xuanwo

IMO, we should implement the Redis Sentinel support as a part of the OpenDAL. And just use it here.

Possibly, it's already done.

[ex0a]

Thanks for the review! I've pushed updates addressing both points:
Feature gating: redis has been restored to the all feature list and the redis crate dependency is now properly optional via dep:redis, so it won't be compiled in unless the redis feature is enabled. I've also removed the hard tracing dependency I accidentally added.
Credentials warning: Added a warn!() when username, password, or db are provided alongside a redis-sentinel:// URL, since those fields are ignored in sentinel mode (credentials should be embedded in the URL itself).
Regarding OpenDAL: I considered this approach, but OpenDAL's Redis service doesn't currently support Sentinel natively. My implementation handles discovery at the sccache layer — querying sentinels to resolve the current master address, then building a normal single-node OpenDAL connection to it. This keeps the OpenDAL layer unchanged and avoids requiring upstream OpenDAL changes. Happy to revisit if OpenDAL adds Sentinel support in the future.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 9.61538% with 94 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.54%. Comparing base (1b480c9) to head (b477146).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/cache/redis.rs	0.00%	88 Missing ⚠️
src/cache/cache.rs	62.50%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2618      +/-   ##
==========================================
- Coverage   72.74%   72.54%   -0.20%     
==========================================
  Files          68       68              
  Lines       36985    37079      +94     
==========================================
- Hits        26903    26900       -3     
- Misses      10082    10179      +97     

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[sylvestre]

please fix the jobs