Ports & Adapters Architecture - XP Days 2017
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Ports & Adapters Architecture Inside & Outside Application Thinking Nathan Johnstone - Technical Pathfinder @ Coolblue
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Transcript of Ports & Adapters Architecture - XP Days 2017
Ports & Adapters Architecture
Inside & Outside Application Thinking
Nathan Johnstone - Technical Pathfinder @ Coolblue
Focus
A Bit About Me ...
A Bit About Me ...
Pigs != Pegs
The Starting Point
Joining a Team
Infrastructure Dependencies
Web APIMessage Service Scheduler
Application Assemblies
Web APIMessage Service Scheduler
Data Access Domain Common
Application Dependencies
Web APIMessage Service Scheduler
Data Access Domain Common
Class Library Dependencies
Web APIMessage Service Scheduler
Data Access Domain Common
N-Tier
Web API
Data Access
Domain
Isn't Something Missing ?
Pain
Leakage
DRY - Reuse Reuse Reuse !
Test Coverage
Unit Tests
Component Tests
Acceptance Tests
Integration Tests
Implementing Integration Tests
Interfaces Colocated With Implementations
Data Access Domain
PurchaseOrderSubmitServiceIPurchaseOrderRetriever
PurchaseOrderRetriever
?
Who Owns The Interface ?
Colocation Problems
Data Access Domain
PurchaseOrderSubmitServiceIPurchaseOrderRetriever
PurchaseOrderPurchaseOrderDocument
Isolation Violation
PurchaseOrderDocument
Domain
Reference Direction vs Control Direction
Presentation Layer
Data AccessLayer
Business LogicLayer
Reference DirectionControl Direction
Ports & Adapters Introduction
Allow an application to equally be driven by users, programs, automated test or batch scripts, and to be developed and tested in isolation from its eventual run-time devices and databases.
Hexagonal Architecture
Inside Outside Architecture
First Port - Persistence
Web APIMessage Service Scheduler
Data Access Domain Common
PersistenceAdapter
Mikado Method
Second Port - Commands
Web APIMessage Service Scheduler
Data Access Domain
PersistenceAdapter
CommandAdapter
Upstream & Downstream Ports
Third Port - Notification
Web APIMessage Service Scheduler
Data Access Domain
PersistenceAdapter
CommandAdapter
NotificationAdapter
Clean Up
Web APIMessage Service Scheduler
Data Access Domain
PersistenceAdapter
CommandAdapter
NotificationAdapter
Hexagonal - Domain
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Hexagonal - Persistence Port
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Hexagonal - Command Port
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Hexagonal - Notification Port
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Notification Port
Hosts Are Types of Adapters
Web Service
Test Harness
Command Line
Daemon
Windows Service
Graphical UI
Hexagonal - Host Port
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Notification Port
Host Port
Advantages - Domain Testability
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Notification Port
Host Port
Advantages - Boundaries
Web APIMessage Service Scheduler
Domain
PersistenceAdapter
CommandAdapter
NotificationAdapter
Advantages - Alternative Adapters
Domain
Web APIMessage Service Scheduler
Persistence.Adapter Command.Adapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Notification Port
Host Port
Persistence.AdapterCsv
Command.AdapterFile
Notification via SMTP
Domain
Web APIMessage Service Scheduler
PersistenceAdapter
CommandAdapter
NotificationAdapter
Persistence
Port
Com
man
d Po
rt
Notification Port
Host Port
Code Examples - Book Ordering Service
Book Ordering Service - Client 1
● REST endpoints for adding books,
approving and submitting
● Notification to supplier to be via SMTP
● Persistence to MySQL
Book Ordering Service - Client 2
● RabbitMq message for adding books
● REST endpoints for adding approving and
submitting
● Notification to supplier to be via
RabbitMq message
● Persistence to MySQL
Book Ordering Service - Architecture
Domain
Host
Web APIClient 1
Web API Client 2
Pers
isten
ce
MySQLNotification
SMTPRabbitMq
Comm
andRabbitMq
Warning Live Code Demo Ahead !
Takeaways● Ports are just a name given to a common group of abstractions in your
domain
● Adapters are a group of specific implementations of a given port
● Onion Architecture, Clean Architecture and Ports & Adapters are essentially the same thing
● Example repository on github for .NET
● Ports & Adapters is an architectural style that will produce applications that are independent of infrastructure details
Links● http://alistair.cockburn.us/Hexagonal+architecture
● http://blog.ploeh.dk/2013/12/03/layers-onions-ports-adapters-its-all-the-same/
● https://github.com/nrjohnstone/ports-adapters-examples
● https://www.linkedin.com/in/nrjohnstone
● https://nathanjohnstone.wordpress.com/
