Background

Multiple systems in the kcenon ecosystem maintain their own Dependency Injection (DI) container implementations:

The common_system::service_container is the most feature-complete implementation, providing:

• Thread-safe registration and resolution
• Service lifetimes: singleton, transient, scoped
• Circular dependency detection
• Container freezing for security
• Global singleton instance

Having multiple DI containers creates:

1. Cognitive overhead — developers must learn different registration patterns per system
2. Integration friction — cross-system service resolution requires adapter boilerplate
3. Inconsistent lifecycle management — each container handles lifetimes differently
4. Testing complexity — mock injection differs across systems

Scope

Phase 1: Audit and compatibility analysis

• Catalog all DI container usages in logger_system, monitoring_system, and database_system
• Identify feature gaps between service_container and system-specific containers
• Document required service_container enhancements (if any)

Phase 2: Enhance common_system service_container (if needed)

• Add any missing features identified in Phase 1
• Ensure lightweight registration path for systems with minimal DI needs
• Add ecosystem module registration helpers

Phase 3: Migrate logger_system

• Replace lightweight_di_container with service_container registration
• Update writer/formatter/filter factory patterns
• Verify all logger_system tests pass

Phase 4: Migrate monitoring_system

• Replace service_registration with service_container integration
• Update collector and exporter factories
• Verify all monitoring_system tests pass

Phase 5: Migrate database_system

• Refactor database_context to use service_container for backend resolution
• Update adapter initialization patterns
• Verify all database_system tests pass

Acceptance Criteria

• common_system::service_container is the single DI container used across all systems
• System-specific DI containers are removed (no dead code)
• Cross-system service resolution works through a single container instance
• All tests pass across all affected systems under ASAN and TSAN
• No regressions in CI across all platforms
• Migration guide documented for downstream consumers

Related Files

common_system:

• include/kcenon/common/di/service_container.h
• include/kcenon/common/di/service_container_interface.h

logger_system:

• src/impl/di/lightweight_di_container.h

monitoring_system:

• include/kcenon/monitoring/di/service_registration.h

database_system:

• database/integrated/core/database_coordinator.h
• database/integrated/adapters/

Related Systems

• kcenon/logger_system — has own lightweight DI
• kcenon/monitoring_system — has own service registration
• kcenon/database_system — has own database_context DI pattern