Software Design & System Design

Table of Contents

• Introduction
• System Design
  • Basic Principles of System Design
  • Documentations
  • Databases
  • Communication Between Components
  • Practical Case Studies
  • Recommended Reading
• Software Design
  • Basic Principles of Software Design
  • Design Patterns
  • Introduction to Domain-Driven Design (DDD)
  • Recommended Reading

Introduction

• Software Design vs Software Architecture

• System Design vs Software Design

• Importance of understanding both for software engineers

• Overview of the topics covered in this document

System Design

Basic Principles of System Design

• Tiers vs layers

• System components: front-end, back-end, databases, caches

• Scalability: vertical vs horizontal

• Latency and throughput: how to optimize both

Documentations

• How to document a system design

• Use of diagrams (UML, C4 model)

• Importance of clear and concise documentation

• Documentation as code — Why documentation as code is important?

Databases

• SQL

• NoSQL

• NewSQL

• CAP / PACELC

• ETL (Extract, Transform, Load)

• ELT (Extract, Load, Transform)

• Data warehousing and data lakes

• Designing Scalable Systems — Data partitioning (sharding) — Load balancers — Use of caches (Redis, Memcached) for optimization — Distributed databases and replication

Communication Between Components

• Synchronous APIs (REST, gRPC)

• Asynchronous communication with queues and message brokers (Kafka, RabbitMQ)

• Robust interface design for integration

• High Availability and Fault Tolerance — Resilient projects with Circuit Breakers and retries — Replication and failover strategies — Tools for monitoring and automatic recovery (auto-healing)

Practical Case Studies

• High-scale e-commerce (like Amazon)

• Reservation system (like Uber or Booking)

• Social media feed (like Instagram or Twitter)

Recommended Reading

• Xu, A. (2020). System Design Interview – An Insider’s Guide. ByteByteGo. https://www.amazon.com.br/dp/B08B3FWYBX/

• Xu, A. (2021). System Design Interview – An Insider’s Guide, Volume 2. ByteByteGo. https://www.amazon.com.br/dp/1736049119/

Software Design

Basic Principles of Software Design

• Why? — The cost of bad software design

• SOLID principles

• Single Responsibility Principle (SRP)

• Open/Closed Principle (OCP)

• Liskov Substitution Principle (LSP)

• Interface Segregation Principle (ISP)

• Dependency Inversion Principle (DIP)

• DRY (Don’t Repeat Yourself)

• KISS (Keep It Simple, Stupid)

• YAGNI (You Aren’t Gonna Need It)

• Separation of Concerns

• Composition over Inheritance

• Law of Demeter (Principle of Least Knowledge)

• Coupling and Cohesion

• Encapsulation

• Code readability and maintainability

• Testability and TDD (Test-Driven Development)

• Refactoring and code smells

Design Patterns

• Why use design patterns?

• Singleton

• Factory

• Strategy

• Observer

• Builder

• Prototype

• Adapter

• Decorator

• Proxy

Introduction to Domain-Driven Design (DDD)

Strategic DDD

• Bounded Context

• Context Mapping

• Ubiquitous Language

• Patterns of integrations

Tactical DDD

• Patterns

• Overview

• Entity

• Aggregator

• Repository

• Coupling/Decoupling

• Refactoring

Recommended Reading

• Martin, R. C. (2008). Clean Code: A Handbook of Agile Software Craftsmanship. Prentice Hall.

• Ousterhout, J. (2021). A Philosophy of Software Design (2nd ed.). Yaknyam Press.

• Khononov, V. (2021). Balancing Coupling in Software Design: Universal Design Principles for Architecting Modular Software Systems. Manning Publications.

• Fowler, M. (2018). Refactoring: Improving the Design of Existing Code (2nd ed.). Addison-Wesley.

• Beck, K. (2023). Tidy First?: A Personal Exercise in Empirical Software Design. Oddprint.