Wh op ps! W hf re did my archi tf cture go? In betw ef n a m oo olith - PowerPoint PPT Presentation

Wh op ps! W hf re did my archi tf cture go? In betw ef n a m oo olith ao d a sys tf m of sys tf ms mess… � / � @ olivergierke

Background C oo sulting & engin ef ring @ Pivotal Lots of code reviews Eoin W op ds‘ talk oo InfoQ

Roadmap Divide ao d c oo quer Of l az ers ao d slices T hf modular m oo olith

Divide and conquer

Comp oo ent Single unit to underst ao d

Comp oo ent Single unit to ch ao ge

Comp oo ent Scope of r it k of ch ao ge

A B Sma lm er unit to underst ao d

A B Reduced r it k of ch ao ge

A B Cost of sf parati oo

A B Definiti oo ao d main tf n ao ce of dependencies

Of layers and slices…

Bi lm ing Inventory Order Pre sf ntati oo Service Data Access

Layers We lm underst op d Known to developers Less import ao t to business

Slices Hardly underst op d New to developers Key for business requirements

Bi lm ing Inventory Order Pre sf ntati oo Service Data Access

Monolith 
 VS. System of Systems

Order Order Bi lm ing Bi lm ing Inventory Inventory M oo olith VS. Sys tf m of Sys tf ms

Order Order Bi lm ing Bi lm ing Inventory Inventory In-process ca lm s VS. In tf r-process ca lm s

Order Order Bi lm ing Bi lm ing Inventory Inventory Perform ao ce? Over hf ad? Error scenarios?

" If you can’t build a modular monolith, why do you think microservices are the answer? — Simon Brown

How to manage modularity in different architectural contexts?

Order Order Bi lm ing Bi lm ing Inventory Inventory Me ao s to enforce c ootf xt b ov ndaries?

The modular monolith

How to implement 
 a modular monolith?

How to maintain 
 a modular monolith?

Bounded Context 
 all the things! Domain-Driven Design it a great idea! Surpr it e! In a m oo olith, t op !

Architecturally- evident code

Code analysis jDepend S oo arcube Structure 101 / S oo argraph jQAss it t ao t

A plain Java based approach

How to write code that’s less likely to deteoriate?

Bi lm ing Inventory Orders Pre sf ntati oo Service Data Access

Packages

….layer.slice ….slice.layer ….slice

….web.core ….service.core ….repository.core

….core.web ….core.service ….core.repository

….core ….customer ….account

Does it make a difference?

Dependency management

Orders Orders Bi lm ing Bi lm ing Inventory Inventory

Orders Bi lm ing Inventory A rule violati oo it just ao @Inject aw az !

You only need to manage 
 what you can refer to…

Layers first Lea kt slice in tf rna lt Lower l az ers v it ible to every oo e

N ef ds to be public :( A lm ows ot hf r code to circumvent business logic

Slices only K ef ps tf chnical div it i oo priva tf Encapsula tf s business module In tf rna lt underst op d ao yw az

A lm package pro tf c tf d Compiler induced dependency c oo trol

Bi lm ing Inventory Order Pre sf ntati oo Service Data Access

Bi lm ing Inventory Order Pre sf ntati oo Service Data Access

Resources Blogpost S oo argraph jQAss it t ao t Spring Data JPA @ GitHub

Sample Code http://github.com/olivergierke/ 
 wh op ps-archi tf cture

Thanks & Credits Eoin W op ds — Talk @ InfoQ S tf f ao Tilkov — Talk @ InfoQ