AuthZService: improve authz caching

[everettbu]

Test 2

Summary by CodeRabbit

• New Features

  • Introduced a permission denial cache to improve performance by quickly returning denied responses for repeated permission checks.
  • Enhanced permission caching logic for more efficient authorization checks and permission listing.

• Bug Fixes

  • Improved cache handling to ensure accurate permission results and prevent outdated cache entries from allowing unauthorized access.

• Tests

  • Added comprehensive tests for permission check and list methods with cache scenarios.
  • Removed redundant cache test to streamline the test suite.

[coderabbitai]

Walkthrough

The changes introduce a permission denial cache to the RBAC authorization service, enabling immediate denial responses for cached denials. The code refactors cache handling for permission checks, adds a unified method for retrieving cached permissions, and updates related tests. A new no-op cache implementation and a cache key generator for denials are also added.

Changes

File(s)	Change Summary
pkg/services/authz/rbac.go	Refactored RBAC client instantiation; removed helper, added NoopCache, and updated cache usage.
pkg/services/authz/rbac/cache.go	Added userPermDenialCacheKey function for generating denial cache keys.
pkg/services/authz/rbac/service.go	Added permDenialCache, unified cache retrieval, updated Check/List methods, and denial caching logic.
pkg/services/authz/rbac/service_test.go	Added tests for denial and permission caches, removed redundant cache test, updated setup.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant Service
    participant DenialCache
    participant PermCache
    participant Store

    Client->>Service: Check(namespace, user, action, name, parent)
    Service->>DenialCache: Get(denialKey)
    alt Denial found
        DenialCache-->>Service: Denied
        Service-->>Client: Denied (cached)
    else Denial not found
        Service->>PermCache: Get(permKey)
        alt Permission found and allows
            PermCache-->>Service: Allowed
            Service-->>Client: Allowed (cached)
        else Permission not found or denied
            Service->>Store: Fetch permissions
            Store-->>Service: Permissions
            alt Denied
                Service->>DenialCache: Set(denialKey, true)
                Service-->>Client: Denied
            else Allowed
                Service-->>Client: Allowed
            end
        end
    end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

A cache for denials, a hop for the best,
Now rabbits can rest when permissions are stressed.
With keys made precise and a Noop in the mix,
The service is nimble with clever new tricks.
Hooray for the caches, both deny and allow—
This bunny approves of the changes right now!
🐇✨

Note

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between e650fa7 and d9dc93c.

📒 Files selected for processing (4)

• pkg/services/authz/rbac.go (3 hunks)
• pkg/services/authz/rbac/cache.go (1 hunks)
• pkg/services/authz/rbac/service.go (6 hunks)
• pkg/services/authz/rbac/service_test.go (3 hunks)

🔇 Additional comments (10)

pkg/services/authz/rbac/cache.go (1)

30-32: LGTM! Cache key function follows established patterns.

The new userPermDenialCacheKey function correctly follows the existing naming convention and key structure pattern used by other cache key functions in this file.

pkg/services/authz/rbac.go (2)

101-105: Good refactoring - direct client instantiation improves clarity.

Removing the helper function and directly calling authzlib.NewClient with explicit options makes the code more readable and explicit about the caching strategy for in-process clients.

---

239-251: NoopCache implementation is correct and well-designed.

The NoopCache correctly implements the cache interface with no-op methods. Returning cache.ErrNotFound from Get ensures proper cache miss behavior, while Set and Delete appropriately do nothing.

pkg/services/authz/rbac/service_test.go (3)

893-996: Comprehensive test coverage for cache behavior.

The TestService_CacheCheck function provides excellent coverage of the caching scenarios including:

• Cache hits for allowed permissions
• Fallback behavior on cache misses
• Handling of outdated cache entries
• Explicit denial cache functionality

The tests are well-structured and verify the expected behavior thoroughly.

---

1291-1323: Good test coverage for cached list operations.

The TestService_CacheList function properly tests the caching behavior for list operations, verifying that cached permissions are correctly used.

---

1336-1336: Setup function correctly updated.

The setupService helper properly initializes the new permDenialCache field.

pkg/services/authz/rbac/service.go (4)

56-61: LGTM! Denial cache field properly added to Service struct.

The permDenialCache field is correctly typed and follows the same pattern as other cache fields in the struct.

---

116-121: Excellent optimization - early denial check improves performance.

Checking the denial cache before attempting any permission lookups is an effective optimization that short-circuits denied requests immediately. The metrics are correctly updated to track cache usage.

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153-155: Good caching strategy for denied permissions.

Caching denied permissions after a failed check will help optimize subsequent denial checks for the same permission.

---

342-368: Well-designed unified cache retrieval method.

The getCachedIdentityPermissions method effectively consolidates cache retrieval logic for different identity types. The method correctly:

• Handles each identity type appropriately
• Returns cache.ErrNotFound for render service (which doesn't use caching)
• Retrieves user identifiers before checking user cache
• Returns proper error types for cache misses

This unification improves code maintainability and consistency.

✨ Finishing Touches

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• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch authz-service-improve-caching-pr

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[everettbu]

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[github-actions]

This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 2 weeks if no further activity occurs. Please feel free to give a status update or ping for review. Thank you for your contributions!

[github-actions]

This pull request has been automatically closed because it has not had any further activity in the last 2 weeks. Thank you for your contributions!