Enforce Layer Boundaries in Architecture

[wen-templari]

Problem Statement

The current codebase has layer boundary violations that compromise the clean architecture:

• Router layer directly calls Repository layer, bypassing Service layer
• Business logic mixed in Router layer instead of being encapsulated in Service layer
• Global singletons creating tight coupling and testing difficulties

Examples of Violations

// router/member.go:96 - Direct repo call
memberId, err := repo.GetMemberIdByLogtoId(user.Id)

// router/member.go:105-117 - Business logic in router
logto_roles, err := service.LogtoServiceApp.FetchUserRole(user.Id)
mappedRole := service.MemberServiceApp.MapLogtoUserRole(logto_roles)

Proposed Solution

Implement a 4-phase plan to enforce proper layer boundaries:

Phase 1: Analysis & Interface Design (Week 1)

• Audit current layer boundary violations
• Create service interface definitions
• Map business logic currently in router layer

Phase 2: Refactor Router Layer (Week 2-3)

• Eliminate all direct repository calls from router
• Move business logic from router to service layer
• Standardize router handler patterns

Phase 3: Service Layer Enhancement (Week 3-4)

• Implement dependency injection to replace global singletons
• Consolidate business logic in service layer
• Create proper service constructors with interface dependencies

Phase 4: Architectural Safeguards (Week 4-5)

• Create architecture tests to prevent future violations
• Implement CI checks for layer boundary compliance
• Update documentation with layer boundary rules

Benefits

• Improved Testability: Each layer can be unit tested independently
• Better Maintainability: Clear separation of concerns
• Reduced Coupling: Dependency injection eliminates global state
• Consistent Patterns: Standardized approach across all handlers

Implementation Strategy

• Service-by-Service Migration: Refactor one service at a time
• Backward Compatibility: Maintain existing functionality during transition
• Comprehensive Testing: Ensure no regression during refactoring

Success Criteria

• Zero direct repository calls from router layer
• All business logic encapsulated in service layer
• Dependency injection implemented for all services
• Architecture tests passing in CI
• Documentation updated with layer boundary guidelines

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Priority: High
Effort: ~4-5 weeks
Impact: Significant improvement in code maintainability and testability

[wen-templari]

Progress Update - Phase 1 & 2 Partial Completion

✅ Completed Tasks

Phase 1: Analysis & Interface Design

• Comprehensive violation audit completed
• Service interfaces created in /service/interfaces.go

Phase 2: Router Layer Refactoring (Partial)

• Critical violation fixed: Eliminated direct repo.GetMemberIdByLogtoId() call in router/member.go:96
• Business logic moved to service: Created AuthenticateAndSyncMember() method in MemberService
• Router simplified: CreateTokenViaLogtoToken function reduced from 55 lines to 8 lines
• Removed repo import from router/member.go

🔧 Technical Changes Made

New Service Methods Added:

// service/member.go
func (service *MemberService) GetOrCreateMemberByLogtoId(logtoId string) (model.Member, error)
func (service *MemberService) AuthenticateAndSyncMember(logtoToken string) (model.Member, string, error)
func (service *MemberService) SyncMemberProfile(member model.Member, logtoUser *FetchLogtoUsersResponse) error

Router Refactoring:

• Before: Complex 55-line authentication logic mixed in router
• After: Clean 8-line delegation to service layer

🎯 Impact Achieved

• Layer boundary violation eliminated: No more direct repo calls from router
• Business logic centralized: Authentication flow now properly encapsulated in service layer
• Code maintainability improved: Complex logic moved to appropriate layer
• Testing readiness: Service methods can now be unit tested independently

📋 Next Steps

• Continue with event router layer violations
• Implement dependency injection for service layer
• Create architecture tests to prevent future violations

Build Status: ✅ Application compiles successfully after changes