Design principles for an event driven architecture Madrid Apache Kafka Meetup Luis García & Pablo Ruiz - ING October 2019 

Introduction 2 There is a perfect pairing between microservice-based architectures, Domain Driven Design (DDD) and event-driven architectures 

3 

Event Taxonomy 4 Purpose Driven Technical Meaning Driven Business Domain Raw Native Standardized Atomic raw domain Derived (*) business 

Taxonomy at microservice level 5 (*) each bus represents one specific topic in the Event Bus Domain API BB viewed from the outside Business Technical API Storage Bus Connector CORE Raw Domain Building Block internals Business Technical 

Standard language 6 API Call API Call Ubiquitous Language Ubiquitous Language Ubiquitous Language Standard Language 

Bounded Context Bounded Context Cohesion (strong) 7 Producer Consumer Schema Registry Send Schema Read Schema DB DB 

Reference Data 8 Building Block A Building Block B Master Reference Data Building Block C Datalake 

Coupling (loose) 9 Product A transaction received Fraud Engine transaction received Fraud Alert!! Communications transaction received Contact customer!! Channel Gateway Contact customer!! 

Correlation & Inference 10 Domain A Event A Domain B Domain C Event B Domain A Event A Domain B Domain C A & B A & NOT B 

Traceability & Lineage 11 Domain A Event Id: 1 TraceID: 1 Domain B Domain C Event Id: 2 TraceID: 1 Event Id: 3 TraceID: 1 Event Id: 4 TraceID: 1 Domain D Event Id: 5 TraceID: 5 

Aggregation / enrichment 12 Domain A Domain B Domain C Name: Peter Surname: Parker Job: Photographer Name: Peter Surname: Parker Alias: Spiderman Domain D Name: Peter Surname: Parker 

Orchestration 13 Orchestrator Generate Monthly Extract Product A Product B Document Mgm Product A movements Product B movements Statement request with Product A&B movements 

Choreography 14 Product A transaction received Category Service transaction received transaction categorized Customer Reporting transaction received transaction categorized 

Reconciliation 15 Domain A Domain B Domain C Domain D Reconciliation? Reconciliation? 

Privacy / Data Segregation 16 Producer Clear Message Clear Message Producer Consumer Name: Clark Surname Kent Income: 1234.00 Name: Clark Surname Kent Income: 1234.00 Other Consumer Name: **** Surname ***** Income: 1234.00 Consumer Other Consumer 

Technical/Business Monitoring 17 Domain A Domain B Domain C Alerting 

How EDA impacts a microservice based architecture 18 Feature EDA impact Loosely coupled Location transparency Strong cohesion Organized around business capabilities Each service is independently deployable Highly maintainable – Easy to maintain Highly testable – Easy to test Each service is as simple as possible Data Management Transaction Management 

Thank you!! Questions? 19