add Redis Sentinel support #9787

PHP Version

8.4

CodeIgniter4 Version

4.6.3

CodeIgniter4 Installation Method

Composer (using codeigniter4/appstarter)

Which operating systems have you tested for this bug?

Linux

Which server did you use?

apache

Database

SQLServer 2019

What happened?

CodeIgniter 4 currently supports Redis for cache and session management, but does not provide built-in support for Redis Sentinel. This limits high availability and automatic failover capabilities for applications using Redis clusters.

Steps to Reproduce

1. Configure CodeIgniter 4 to use Redis for cache or session storage.
2. Attempt to connect to a Redis cluster managed by Sentinel using the current configuration options.
3. Observe that there is no way to specify Sentinel hosts or master name, and failover is not handled automatically.

Expected Output

• CodeIgniter 4 should allow configuration of Redis Sentinel hosts and master name for cache and session management.
• The framework should automatically discover the current master node via Sentinel and handle failover seamlessly.
• Applications should remain highly available and continue to function even if the Redis master changes.
• For reference, see how Symfony implements Redis Sentinel support:
  https://symfony.com/doc/current/components/cache/adapters/redis_adapter.html#configure-the-connection

Anything else?

No response