aitbc/docs/MICROSERVICES_ARCHITECTURE_EVALUATION.md

Microservices Architecture Evaluation

Date: 2026-05-09
Purpose: Evaluate whether AITBC should evolve toward a microservices architecture

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Current Architecture Assessment

Current State

AITBC currently uses a monolithic architecture with the following characteristics:

Components:

• Blockchain node (single service)
• Agent daemon (single service)
• API gateway (single service)
• Wallet service (single service)
• Marketplace service (single service)
• Monitoring service (single service)

Data Layer:

• SQLite databases per service
• Redis for caching
• S3 for object storage

Communication:

• HTTP/REST APIs
• Event bus for async communication
• Direct blockchain RPC calls

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Evaluation Criteria

1. Service Independence

Current Status: Partial

• Services share some code (aitbc package)
• Some services have tight coupling (wallet + blockchain)
• Event bus provides some decoupling

Assessment: Medium service independence. Some refactoring needed for full independence.

2. Data Ownership

Current Status: Shared

• Each service has its own SQLite database
• Some cross-service data access required
• No clear data ownership boundaries

Assessment: Data ownership is not clearly defined. This would be a major challenge for microservices.

3. Deployment Independence

Current Status: Low

• Services deployed together in most environments
• Shared infrastructure dependencies
• Coordinated deployments required

Assessment: Low deployment independence. Significant infrastructure changes needed.

4. Scaling Requirements

Current Status: Low

• Most services are not horizontally scalable
• Blockchain node has specific scaling needs
• Current load does not require independent scaling

Assessment: Scaling requirements are minimal. Microservices would add complexity without clear benefit.

5. Team Size

Current Status: Small team

• Development team is small
• Clear ownership of components
• Communication overhead is low

Assessment: Small team size doesn't justify microservices complexity. Monolith is more suitable.

6. Technology Diversity

Current Status: Low

• All services use Python
• Shared libraries and dependencies
• Consistent tech stack

Assessment: Low technology diversity. No need for microservices to enable different tech stacks.

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Microservices Pros/Cons

Pros

1. Independent Scaling: Each service can scale independently
2. Fault Isolation: Failure in one service doesn't affect others
3. Technology Flexibility: Different services can use different technologies
4. Faster Development: Smaller teams can work independently
5. Easier Deployment: Deploy individual services without full redeploy

Cons

1. Increased Complexity: More moving parts to manage
2. Network Latency: Inter-service communication adds latency
3. Data Consistency: Distributed transactions are complex
4. Operational Overhead: More infrastructure to monitor and maintain
5. Testing Complexity: Integration testing becomes harder

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Recommendation

Recommendation: Remain Monolithic with Modular Architecture

Rationale:

1. Team Size: Small development team doesn't benefit from microservices complexity
2. Scaling Needs: Current load doesn't require independent scaling
3. Data Complexity: Shared data access patterns make microservices difficult
4. Operational Overhead: Current team lacks DevOps capacity for microservices
5. Maturity: Monolith is more mature and stable

Alternative: Modular Monolith

Instead of full microservices, implement a modular monolith:

Benefits:

• Clear module boundaries (similar to microservices)
• Single deployment unit (simpler operations)
• Shared database (avoid distributed transactions)
• Easier to evolve to microservices if needed later

Implementation:

1. Define clear module boundaries based on domain
2. Implement service layer for each module
3. Use event bus for inter-module communication
4. Maintain shared database with clear ownership
5. Implement feature flags for gradual feature rollout

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Migration Path (If Microservices Needed Later)

If future requirements dictate microservices architecture, follow this path:

Phase 1: Modularization (Current)

• Define clear module boundaries
• Implement service layers
• Add feature flags
• Improve monitoring

Phase 2: Database Separation

• Identify data ownership per module
• Implement database per service
• Add data migration scripts
• Implement API-based data access

Phase 3: Service Extraction

• Extract one service at a time
• Start with low-risk services (monitoring)
• Use feature flags for gradual rollout
• Maintain dual-write during migration

Phase 4: Full Microservices

• Complete service extraction
• Implement service mesh (if needed)
• Add distributed tracing
• Implement circuit breakers

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Conclusion

AITBC should remain a monolithic application with modular architecture.

The current architecture is appropriate for the team size, scaling requirements, and operational capacity. Implementing a modular monolith provides most microservices benefits without the complexity overhead.

Revisit this evaluation when:

• Team size grows beyond 10 developers
• Independent scaling becomes necessary
• Different technology stacks are required
• Service failure isolation becomes critical

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Next Steps

1. Implement Modular Monolith

   • Continue current modularization efforts
   • Define clear module boundaries
   • Implement service layers

2. Improve Monitoring

   • Add distributed tracing (completed)
   • Improve metrics collection
   • Add alerting

3. Enhance Deployment

   • Implement blue-green deployments (completed)
   • Add feature flags (completed)
   • Improve rollback capabilities

4. Prepare for Future

   • Document module boundaries
   • Identify data ownership
   • Plan for potential future migration