zee-solution/docs/architecture.md

GUIDE

This document outlines the technical architecture and organization of the project. It details the high-level architectural design, the rationale behind the codebase structure, descriptions of key functional components, and illustrates primary data flows within the system. The aim is to provide a clear and comprehensive guide for developers and architects involved with the project.

FORMAT

Title: [Application/Website Name]

app_ver: [app_ver] doc_ver: [doc_ver]

1. Architecture Overview

[Explanation of the overall architecture model (e.g., Microservices, Monolithic, Layered). Brief description of the main parts of the system and their high-level relationships. Can include a high-level architecture diagram (if available).]

2. Project Structure

[Brief overview of how the directory structure organizes the codebase and the reasoning behind this organization.]

Directory Tree

A/ ├── B/ │   ├── C/        # [Brief explanation] │   │   ├── C1/   # [Brief explanation] │   │   └── C2/   # [Brief explanation] │   ├── D/        # [Brief explanation] │   │   ├── D1/ # [Brief explanation]

Structure Explanation

[More detailed explanation of the roles and responsibilities of the main layers and directories. Why this structure was chosen.]

3. Key Components

[Numerical order]. [Component Name]

• Description: [Detailed description of the component's function and responsibilities.]
• Location in Directory Tree (if relevant): [Directory path]
• Dependencies: [List of components this component depends on]
• Interactions with Other Components: [Description of how this component interacts with other parts of the system.]

4. Main Data Flow

[Description of the most important data flows in the system, such as user creation flow, order processing flow. Can use a Mermaid diagram for visualization.]

[mermaid flow chart here]

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CONTENT

Title: ZEE Quiz Application

app_ver: 1.0.0 doc_ver: A1

1. Architecture Overview

1.1. System Architecture

The ZEE Quiz Application follows a modular monolith architecture with Domain-Driven Design (DDD) principles. This approach provides the right balance between maintainability and development velocity while keeping the system simple to deploy and operate.

Key Architectural Principles:

• Domain-Driven Design (DDD) for clear domain boundaries
• Clean Architecture for separation of concerns
• Container-First design for cloud-native deployment

1.2. High-Level Architecture

graph TD
    Client[Web Client] --> HTTP[HTTP Transport Layer]
    HTTP --> Handler[Request Handlers]
    Handler --> Service[Business Services]
    
    subgraph Internal Resources
        Service --> User[User Resource]
        Service --> Role[Role Resource]
    end
    
    subgraph Infrastructure
        User --> DB[(PostgreSQL)]
        Role --> DB
        User --> Cache[(Redis)]
        Service --> Logger[Logger]
    end
    
    subgraph Helpers
        Handler --> Config[Config Helper]
        Service --> Feature[Feature Flags]
        DB --> DBUtil[Database Utils]
    end

Component Responsibilities:

1. Transport Layer

   • HTTP request/response handling
   • Route management
   • Middleware (auth, logging, etc.)
   • DTO validation

2. Business Services

   • Core business logic implementation
   • Transaction management
   • Resource coordination
   • Event handling

3. Internal Resources

   • User management
   • Role and permissions
   • Domain logic encapsulation

4. Infrastructure

   • PostgreSQL for persistent storage
   • Redis for caching
   • Structured logging

5. Helper Utilities

   • Configuration management
   • Database utilities
   • Feature flag management
   • Common helper functions

2. Project Structure

2.1. Directory Structure

zee/
├── cmd/                      # Application entry points
│   └── app/                  # Main application server
│
├── configs/                  # Configuration files
│
├── docs/                     # Documentation files
│
├── internal/                 # Private application code
│   ├── adapter/              # External adapters
│   │   └── postgres/         # PostgreSQL adapter
│   ├── helper/               # Helper utilities
│   │   ├── config/          # Configuration helpers
│   │   ├── database/        # Database utilities
│   │   ├── feature/         # Feature flags
│   │   └── logger/          # Logging utilities
│   ├── pkg/                  # Internal packages
│   │   └── lifecycle/       # Application lifecycle
│   ├── resource/             # Domain resources
│   │   ├── role/           # Role management
│   │   └── user/           # User management
│   ├── service/              # Business services
│   └── transport/            # Transport layer
│       └── http/            # HTTP handlers
│           ├── dto/        # Data transfer objects
│           ├── handler/    # Request handlers
│           └── middleware/ # HTTP middleware
│
├── migrations/              # Database migrations
│
└── templates/               # Template files
│   ├── interfaces/        # Interface adapters
│   │   ├── http/          # HTTP handlers
│   │   │   ├── v1/        # API v1 routes
│   │   │   └── middleware # HTTP middleware
│   │   └── repository/    # Repository implementations
│   │
│   └── pkg/              # Shared packages
│       ├── auth/          # Authentication
│       ├── logger/        # Logging
│       └── validator/     # Input validation
│
├── pkg/                   # Public packages
│   ├── errors/            # Common errors
│   └── uuid/              # UUID utilities
│
├── migrations/           # Database migrations
├── web/                   # Frontend assets
├── configs/               # Configuration files
├── scripts/               # Utility scripts
├── .github/               # GitHub workflows
├── docs/                  # Documentation
├── go.mod                 # Go module definition
└── Makefile               # Common tasks

2.2. Structure Explanation

• cmd/api: Contains the application's entry point and server setup
• internal/domain: Core domain models and business logic (DDD)
• internal/application: Application services and use cases
• internal/interfaces: Adapters for external communication (HTTP, repositories)
• internal/pkg: Shared infrastructure code
• pkg: Public reusable packages
• migrations: Database schema migrations
• web: Frontend assets and templates
• configs: Configuration files for different environments

3. Key Components

3.1. API Gateway

• Description: Single entry point for all client requests
• Location: internal/interfaces/http
• Dependencies: Application services, Authentication, Rate limiting
• Responsibilities:
  • Request/response handling
  • Authentication & Authorization
  • Request validation
  • Rate limiting
  • CORS handling

3.2. User Management

• Description: Handles user registration, authentication, and profile management
• Location: internal/domain/user, internal/application/commands/user
• Dependencies: JWT, Password hashing, Email service
• Key Features:
  • User registration with email verification
  • JWT-based authentication
  • Profile management
  • Role-based access control

3.3. Quiz Engine

• Description: Core quiz functionality
• Location: internal/domain/quiz, internal/application/commands/quiz
• Dependencies: Question repository, User repository
• Features:
  • Question management
  • Quiz session handling
  • Timer management
  • Answer validation

3.4. Result Processing

• Description: Handles quiz results and scoring
• Location: internal/domain/result, internal/application/queries/result
• Dependencies: Quiz repository, User repository
• Features:
  • Score calculation
  • Leaderboard generation
  • Result caching
  • Analytics

4. Main Data Flows

4.1. User Registration Flow

sequenceDiagram
    participant C as Client
    participant A as API Gateway
    participant U as User Service
    participant D as Database
    participant E as Email Service

    C->>A: POST /api/v1/register
    A->>U: RegisterUserCommand
    U->>D: Begin Transaction
    U->>D: Check if email exists
    U->>D: Create user
    U->>E: Send verification email
    U->>D: Commit Transaction
    U-->>A: User created
    A-->>C: 201 Created

4.2. Quiz Submission Flow

sequenceDiagram
    participant C as Client
    participant A as API Gateway
    participant Q as Quiz Service
    participant R as Result Service
    participant D as Database
    participant K as Cache (Redis)

    C->>A: POST /api/v1/quizzes/submit
    A->>Q: SubmitQuizCommand
    Q->>D: Load quiz session
    Q->>Q: Validate answers
    Q->>R: CalculateScoreCommand
    R->>D: Save results
    R->>K: Update leaderboard
    R-->>Q: Score calculated
    Q-->>A: Quiz result
    A-->>C: 200 OK with result

5. Technology Stack

5.1. Backend

• Language: Go 1.24.3
• Web Framework: Gin-Gonic Router
• ORM: GORM
• Migrations: GORM Migrate
• Validation: go-playground/validator
• Logging: zap
• Configuration: viper
• Testing: testify, gomock

5.2. Frontend

• HTMX for dynamic UI updates
• TailwindCSS for styling
• Alpine.js for client-side interactions
• HTMX Extensions for advanced functionality

5.3. Infrastructure

• Containerization: Docker
• Orchestration: Docker Compose (local), Kubernetes (production)
• Database: PostgreSQL 14
• Caching: Redis
• Storage: AWS S3
• CI/CD: Gitea Actions
• Monitoring: Prometheus, Grafana
• Logging: ELK Stack

6. Deployment Architecture

6.1. Development Environment

• Local Docker Compose setup
• Hot-reload for development
• Development database with sample data

6.2. Production Environment

• Container orchestration with Kubernetes
• Auto-scaling based on load
• Multi-AZ deployment for high availability
• Automated backups and disaster recovery

7. Security Considerations

7.1. Authentication & Authorization

• JWT-based authentication
• Role-based access control (RBAC)
• Secure password hashing (bcrypt)
• Rate limiting
• CORS policy

7.2. Data Protection

• TLS 1.3 for all communications
• Sensitive data encryption at rest
• Regular security audits
• GDPR compliance

8. Performance Considerations

8.1. Caching Strategy

• Redis for frequently accessed data
• HTTP caching headers
• Database query result caching

8.2. Database Optimization

• Proper indexing
• Query optimization
• Connection pooling
• Read replicas for scaling reads

9. Monitoring & Observability

9.1. Metrics

• Request/response times
• Error rates
• Database query performance
• System resource usage

9.2. Logging

• Structured logging with correlation IDs
• Log levels (debug, info, warn, error)
• Centralized log management

9.3. Alerting

• Error rate thresholds
• Response time thresholds
• System resource alerts
• Business metrics alerts

10. Future Considerations

10.1. Scalability

• Sharding for database scaling
• Event sourcing for audit trail
• CQRS for read/write scaling

10.2. Features

• Real-time leaderboard updates
• Social sharing
• Offline quiz support
• Mobile app integration

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Last Updated: 2025-06-06 Document Version: A1