feat(router): enable using redis clusters for rate limiting and apq

[df-wg]

Motivation and Context

Previously, users were only able to provide a single redis instance to Cosmo for both APQ/Rate Limiting. This didn't take advantage of Redis' built-in cluster mode, which takes care of horizontal scaling for the users.

This PR enables that. In order to do it, users can provide a list of their cluster URLs instead of the singular URL they used to provide, in the now renamed urls field. In order to opt in to cluster mode, users have to set cluster_enabled: true in their configuration for both APQ and Rate Limiting

Warning

As part of the preparations for Cosmo V1, targeted for release in Q1 2025, this pull request introduces essential changes to enhance long-term stability and maintainability. While we strive to minimize breaking changes, they are sometimes necessary to lay the foundation for a more robust and scalable system.

Before:

rate_limit:
  enabled: true
  strategy: "simple"
  storage:
    url: "testuser:testpass@localhost:8000"
    key_prefix: "cosmo_rate_limit"  

storage_providers:
  redis:
    - id: "my_redis"
      url: "test:testpass@localhost:8000"

After

rate_limit:
  enabled: true
  strategy: "simple"
  storage:
    cluster_enabled: true
    urls:
      - "testuser:testpass@localhost:8000"
      - "test2:testpass@localhost:8001"
    key_prefix: "cosmo_rate_limit"  

storage_providers:
  redis:
    - id: "my_redis"
      cluster_enabled: true
      urls:
        - "test:testpass@localhost:8000"
        - "test2:testpass@localhost:8001"

Migration Path:

[ ] Rename storage_providers.redis.url to storage_providers.redis.urls, and rate_limit.storage.url to rate_limit.storage.urls, as the first value of a list

Checklist

• I have discussed my proposed changes in an issue and have received approval to proceed.
• I have followed the coding standards of the project.
• Tests or benchmarks have been added or updated.
• Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• I have read the Contributors Guide.

[github-actions]

Router image scan passed

✅ No security vulnerabilities found in image:

ghcr.io/wundergraph/cosmo/router:sha-eaafdace83a5d516c3369dac1d11b808af5646dd

[StarpTech]

LGTM