index.md

title	Code Architecture Overview
description	Understanding the architecture and design principles of IDP-Core

IDP Core is a Spring Boot app built following the principles of the Hexagonal Architecture.

Key Technologies

• Spring Boot 4
• Spring Security
• Spring Data JPA & PostgreSQL
• Docker & Testcontainers library
• Flyway

Sections

• 🏢 Domain & Infrastructure

  Separation of concerns and folder structure.

• ⚠️ Exception Handling

  Global strategy and error response formats.

• ✅ Validations

  DTO vs Entity validation rules.

• 🎨 Code Conventions

  Coding standards and style guide.

• ⭐ Best Practices

  Checklist for architecture, DB, and security.

Architecture Principles

We strictly separate the Domain (Business Logic) from the Infrastructure (Technical concerns).

Hexagonal Architecture

flowchart LR
    A[Infrastructure - Input Ports] --> B[Domain - Core]
    B --> C[Infrastructure - Output Ports]

    subgraph A[Infrastructure - Input Ports]
        A1[REST API]
        A2[Controllers]
        A3[DTOs]
    end

    subgraph B[Domain - Core]
        B1[Entities]
        B2[Services]
        B3[Exceptions]
    end

    subgraph C[Infrastructure - Output Ports]
        C1[Database]
        C2[Repositories]
        C3[External APIs]
    end

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Core Rules

1. Dependency Rule: Infrastructure depends on Domain. Domain depends on nothing.
2. Testing: Domain is unit-tested. Infrastructure is integration-tested in addition.