Fix MBA-171: Implement REST communication between Spring Boot and Micronaut services

[devin-ai-integration]

Fix MBA-171: Implement REST Communication Between Spring Boot and Micronaut Services

Summary

This PR implements the missing REST communication layer between Spring Boot and Micronaut services to resolve the issue where micronautService field in BankingServiceFacade was always null. The solution includes:

Micronaut Service (REST API):

• Refactored all endpoints from GET with query parameters to POST with request bodies
• Added proper DTO classes for request/response serialization (AccountRequest, AccountResponse, etc.)
• Implemented @SerdeImport annotations for JPA entity serialization
• Added comprehensive error handling with proper HTTP status codes

Spring Boot Service (Feign Client):

• Connected BankingServiceFacade to use the existing MicronautBankingServiceClient with @Autowired
• Configured Feign client properties (timeouts, circuit breaker, logging)
• Added environment variable configuration for Micronaut service URL
• Created matching DTO classes for API communication

Infrastructure:

• Updated Docker Compose to use build contexts and proper service networking
• Added MICRONAUT_SERVICE_URL environment variable for service discovery
• Configured database environment variables consistently across services

Review & Testing Checklist for Human

⚠️ HIGH RISK - 5 Critical Items to Verify

• End-to-End Testing: Start both services with docker-compose up and test full banking operations (register account, deposit, withdraw, transfer) to ensure REST communication works correctly
• JPA Entity Serialization: Verify that Account and Transaction entities serialize properly across service boundaries, especially given Account implements UserDetails and has JPA relationships
• API Contract Alignment: Confirm Feign client method signatures exactly match Micronaut controller endpoints - check request/response DTOs, HTTP methods, and URL paths
• Database Consistency: Test concurrent operations to ensure both services accessing the same MySQL database doesn't cause transaction conflicts or data inconsistencies
• Fallback Mechanism: Stop the Micronaut service and verify Spring Boot gracefully falls back to local AccountService with proper error logging

Notes

• The integration test currently tests injection and fallback scenarios but may need enhancement for full end-to-end validation
• Circuit breaker is enabled in Feign configuration for resilience
• All banking operations now use POST endpoints with request bodies instead of GET with query parameters for better REST design

Link to Devin run: https://app.devin.ai/sessions/9a08bd7858a84228a7a70cb106b513e1
Requested by: @satwik-cog

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring