架構師訓練營 week10 總結

10.1 微服务：服务本身的设计、维护以及治理

monolithic problems

• Hard to complier and deploy 

• Hard to manage code

• Database connection

• Hard to add new features



Web Service - Weaknesses

• bloated register mechanism

• XML low-efficiency serializer

• Slow HTTP connection

• Complicated deployment and maintenance



Microservice requirement

• Failover

• Load balancer

• High-efficiency Communication

• the least injection for an original application

• Versioning





Service mesh



10.2 微服务：落地实践的策略与思路



微服務架構落地

• Business first, figure out business boundary and dependance first. Tech is a means, not a goal

• independent module first, then distributed service

• Seriously look into how to refactor high coupling and complicated system

• What is the purpose? Reuse? Clear development boundary? Distributed system to enhance performance



CQRS - Command and Query Responsibility Segregation

• Clear domain model

• Can performance tunning for read and write



Event tracking

• recover

• monitor



Breaker

• Error handling



Service retry and timeout



The most important thing is requirement

10.3 微服务网关的技术架构

API gateway structure



• Unified access

• Flow control and fault tolerance

• Protocol adapter

• Security



Register center, consumer and service provider





No business logic, mainly focus on validation 



async structure 



• API interface

• Protocol adapter

• security

• Audit: monitor, count

• routing

• Flow - hide internal detail, provide united interface 



Oauth2



10.4 领域驱动设计DDD



貧血模型 (anaemic domain model)

• Service 和 Dao 只有方法，沒有數值成員變量



充血模型 (rich domain model)

• 包含了對象的數據和計算邏輯



DDD 戰略設計

• 限界上下文：限界上下文和子域具有一對一的關係，用來控制子域的邊界，保證子域內的慨念統一性

• 上下文映射圖：不同的限界上下文，也就是不同的仔細或模塊之間會有各種的交互作用，DDD使用上下文映射圖來設計這種關連



DDD 戰術設計

• 實體：把握住實體的特徵是什麼，實體應該承擔什麼職責，分析時要放在業務場景和限界上下文中

• 值對象：DDD推薦盡可能將對象設計為值對象 - 不變性









10.5 软件组件设计原则

內聚原則

• 複用發佈等同原則

• 共同封閉原則

• 共同複用原則

• 不是被共同依賴的類，就不應該放在同一個組件中



耦合原則

• 無循環依賴原則

• 穩定依賴原則

• 穩定抽象原則

• 穩定的組件應該是抽象的

• 不穩定的組件應該是具體的

10.6 案例：用领域驱动设计驱动系统重构