Architecture - .NET Project Architecture Design Framework

🧭 Step 1: Understand the Business and Technical Requirements

🧩 Step 2: Choose the Right .NET Application Type

🧱 Step 3: Select an Architecture Style

🧠 Step 4: Define Solution Structure (Clean Architecture Example)

⚙️ Step 5: Choose Technologies

🧰 Step 6: CI/CD with AWS DevOps

🔒 Step 7: Security & Compliance

🧪 Step 8: Testing, Quality & Observability

📘 Step 9: Documentation & Governance

🔁 Step 10: Iterate and Improve

🧭 Step 1: Understand the Business and Technical Requirements

Before starting, gather and document:

• Functional and non-functional requirements.
• User personas, traffic expectations, and performance needs.
• Compliance, security, and availability goals.
• Integration needs with internal systems or third-party APIs.

🎯 Output: A clear understanding of system goals and constraints.

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🧩 Step 2: Choose the Right .NET Application Type

Application Type	Framework / Tech Stack	Use Case
Web API / Microservice	ASP.NET Core Web API	Backend REST APIs, integrations
Web App (UI)	ASP.NET Core MVC / Razor Pages / Blazor	Full-stack web apps
Background Processing	Worker Service / AWS Lambda	Jobs, scheduling, event processing
Desktop App	WPF / WinUI / MAUI	Desktop or cross-platform apps
Cloud-Native App	ASP.NET Core + Containers (Docker, ECS, EKS)	Scalable distributed systems

🎯 Output: Application type and high-level stack selection.

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🧱 Step 3: Select an Architecture Style

Architecture	Description	Use When
Layered (N-tier)	Simple separation into UI, business, and data layers.	Small to medium monoliths.
Clean / Hexagonal / Onion	Domain-focused, testable, decoupled.	Modern enterprise solutions.
Microservices	Independent, API-based services.	Large, distributed applications.
Modular Monolith	Monolith organized into modules.	Mid-sized apps; future-ready.
Event-driven	Uses AWS SQS/SNS/EventBridge for async comms.	Real-time or decoupled systems.

💡 Recommendation: Start with Clean Architecture for modularity and maintainability.

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🧠 Step 4: Define Solution Structure (Clean Architecture Example)

src/

├── Presentation (API/UI)

│ └── Controllers, Views

├── Application

│ └── Business logic, CQRS, DTOs, Validation

├── Domain

│ └── Entities, Value Objects, Domain Events, Interfaces

├── Infrastructure

│ └── EF Core, AWS SDK integrations, Logging, External Services

└── Tests

└── Unit, Integration, and API tests

Dependency flow: Presentation → Application → Domain → Infrastructure (implementing domain interfaces)

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⚙️ Step 5: Choose Technologies

Backend 

Framework: .NET 8 (LTS)

API: ASP.NET Core Web API / Minimal API

ORM: Entity Framework Core / Dapper

Authentication: JWT, Cognito, or OAuth2

Validation: FluentValidation

Mapping: AutoMapper

Frontend (optional):

React, Angular, Blazor, or Razor Pages

Communicate via REST/gRPC

Database

Amazon RDS (SQL Server, PostgreSQL)

DynamoDB (NoSQL)

EF Core Migrations for schema evolution

Caching

Amazon ElastiCache (Redis)

Messaging / Events

AWS SQS, SNS, EventBridge, or Kinesis Streams

File Storage

Amazon S3

Logging & Monitoring

ILogger (built-in), Serilog, Amazon CloudWatch, X-Ray

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🧰 Step 6: CI/CD with AWS DevOps

• Version control: Git (GitHub / CodeCommit)
• CI/CD: AWS CodePipeline, CodeBuild, GitHub Actions or Harness
• Stages:
• Build and test
• Static analysis (SonarQube / Checkmarx)
• Deploy to dev/test/prod
• Infrastructure as Code (IaC): AWS CloudFormation / Terraform
• Container orchestration: ECS or EKS (Kubernetes)

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🔒 Step 7: Security & Compliance

• Use AWS Identity and Access Management (IAM) for roles and permissions.

• Secure secrets via AWS Secrets Manager or Parameter Store.

• Enable HTTPS using AWS Certificate Manager.

• Apply OWASP Top 10 principles and encryption at rest (KMS).

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🧪 Step 8: Testing, Quality & Observability

• Testing: Unit, Integration, API, and Performance tests.

• Static Code Analysis: SonarQube / Checkmarx.

• Observability: CloudWatch, X-Ray, Serilog.

• Metrics: Track latency, throughput, and error rates.

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📘 Step 9: Documentation & Governance

• Document APIs using Swagger/OpenAPI.

• Maintain Architecture Decision Records (ADRs).

• Use consistent Git branching and code review practices.

• Reassess architecture periodically for improvements.

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🔁 Step 10: Iterate and Improve

• Start with MVP, evolve as usage grows.

• Review scaling patterns regularly.

• Encourage feedback and innovation from the team.

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🧱 Clean Architecture Overview

+---------------------------+

| Presentation |

| (Controllers / API Layer) |

+------------+--------------+

↓

+---------------------------+

| Application |

| (Use Cases, CQRS, DTOs) |

+------------+--------------+

↓

+---------------------------+

| Domain |

| (Entities, Interfaces) |

+------------+--------------+

↓

+---------------------------+

| Infrastructure |

| (EF Core, AWS SDK, etc.) |

+---------------------------+

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✅ Summary Principles

Principle	Description
SOLID	Maintainable and scalable design
KISS & DRY	Simplicity and no duplication
Dependency Inversion	Depend on abstractions
Separation of Concerns	Isolated business logic
Testability	Unit and integration ready
Scalability & Resilience	AWS-native scaling and fault tolerance

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Outcome: A scalable, testable, and secure .NET 8 application leveraging AWS-native services for CI/CD, observability, and automation.