Fix data race in quota group routing by cloning auth in selector

[Copilot]

Race detector revealed concurrent access to auth.Runtime during quota group routing. Manager passed raw auth pointers to selector while MarkResult concurrently modified quota state.

Changes

• manager.go:671 - Clone auth objects before passing to selector

  // Before: selector receives pointer to mutable auth
  candidates = append(candidates, candidate)
  
  // After: selector receives immutable snapshot
  candidates = append(candidates, candidate.Clone())

• quota_group.go - Document that getOrCreateQuotaGroupIndex requires Manager lock (no code change)

• quota_group_race_test.go - Add race detection tests simulating production patterns:

  • TestQuotaGroupIndexManagerProtection - Verifies proper RLock/Lock usage
  • TestConcurrentQuotaPropagation - Tests parallel quota updates
  • TestQuotaGroupIndexConsistency - Validates quota index synchronization
  • TestSelectorWithQuotaGroups - End-to-end concurrent workflow

Impact

Minimal performance overhead (shallow clone + map copies). Eliminates potential crashes and incorrect routing decisions under concurrent load.

All tests pass with -race flag enabled.

Original prompt

Kiểm tra lại cơ chế routing, usage rercod xem có đang gặp vấn đề về logic hoặc gap hay xung đột không

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[nghyane]

@copilot về cơ chế routing thì sao đã kiểm tra chưa?

[Copilot]

@copilot về cơ chế routing thì sao đã kiểm tra chưa?

Đã kiểm tra đầy đủ cơ chế routing, bao gồm:

1. Provider Selection (selectProviders)

• ✅ Circuit breaker filtering hoạt động đúng
• ✅ Performance-based scoring cho multi-provider
• ✅ Fallback khi tất cả breakers open

2. Auth Selection (pickNext → selector.Pick)

• ✅ RoundRobinSelector: Round-robin + sticky sessions (60s TTL)
• ✅ QuotaAwareSelector: Quota-aware + request counting
• ✅ isAuthBlockedForModel: Kiểm tra cooldown, quota, disabled state
• ✅ Quota group index: O(1) lookup cho models chưa init

3. Retry & Failover

• ✅ Retry logic với retry budget (max 100 concurrent)
• ✅ waitForAvailableAuth khi quota exceeded
• ✅ shouldRetryAfterError xử lý user vs provider errors

4. Quota Group Propagation

• ✅ propagateQuotaToGroup: Update ModelStates + quota index
• ✅ clearQuotaGroupOnSuccess: Clear cả hai khi recover
• ✅ Đồng bộ giữa quota index và ModelStates

Data race đã fix (commit 56e8078):

• manager.go:671 - Clone auth trước khi pass cho selector
• Loại bỏ concurrent read/write vào auth.Runtime

Tất cả tests pass với -race flag.

[Copilot]

Pull request overview

This PR fixes a data race in quota group routing where concurrent access to auth.Runtime occurred between MarkResult operations (which modify quota state) and selector operations (which read quota state). The fix ensures thread-safety by cloning auth objects before passing them to selectors.

Key changes:

• Clone auth objects in manager's pickNext method to provide selectors with immutable snapshots
• Add comprehensive race detection tests covering concurrent quota operations
• Document locking requirements for quota group index operations

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/provider/manager.go	Clones auth objects under RLock before passing to selector, preventing race on Runtime pointer
internal/provider/quota_group.go	Documents that getOrCreateQuotaGroupIndex requires Manager lock protection
internal/provider/quota_group_race_test.go	Adds 4 comprehensive race tests validating Manager lock protection, concurrent quota propagation, quota group consistency, and end-to-end selector workflow

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[nghyane]

@copilot Phân tích so sánh với các best practice roubin trong go, các repo api tương tự