CQRS and Event Sourcing Implementation with Kafka and MySQL (JBDC)

Introduction

The aim of this small project is to illustrate the possibility of applying CQRS, Domain-Driven Design and Event Sourcing in a simple way, enabling Reactive architecture and leveraging Kafka as a distributed message broker

See: https://speakerdeck.com/vgoldin/es-and-kafka

Structure

Module	Purpose
`services-core`	core marker interfaces shared between all other modules
`services-infrastructure-eventstore`	multiple event store implementations (JDBM 2.0 and MySQL JDBC)
`services-infrastructure-messaging`	event publisher and command listener implementation with Kafka
`services-intentoryitem-schema`	json-schema's of all the events and commands used in API and Domain services
`services-inventoryitem-api`	API micro-service, exposing RESTfull API, creating Projectin with Hazelcast and dispatching commands to Kafka
`services-inventoryitem-domain`	Domain micro-service, encapsulating Aggregate Root, handling commands and publishing events

Pre-Requisities

JDK 1.8
Maven 3.3.x
(optional) Docker (for Kafka)

Building

mvn clean install

Running Services

Docker Compose

docker-compose build
docker-compose up -d

Standalone

Kafka

docker run -p 2181:2181 -p 9092:9092 --env ADVERTISED_HOST=127.0.0.1 --env ADVERTISED_PORT=9092 spotify/kafka

API Micro-Service

cd services-inventoryitem-api/target
java -jar services-inventoryitem-api-1.0-SNAPSHOT.jar server classes/application-local.yml

Domain Micro-Service

with local jdbm database

cd services-inventoryitem-domain/target
java -jar services-inventoryitem-domain-1.0-SNAPSHOT.jar server classes/application.yml

with MySQL running on 127.0.0.1:3306 (see docker-compose.yml)

cd services-inventoryitem-domain/target
java -jar services-inventoryitem-domain-1.0-SNAPSHOT.jar server classes/application-jdbc.yml

Exposed APIs

GET     /inventory-items (io.plumery.inventoryitem.api.resources.InventoryItemResource)
POST    /inventory-items (io.plumery.inventoryitem.api.resources.InventoryItemResource)
GET     /inventory-items/events.stream (io.plumery.inventoryitem.api.resources.InventoryItemResource)
PUT     /inventory-items/{id} (io.plumery.inventoryitem.api.resources.InventoryItemResource)
POST    /inventory-items/{id}/deactivate (io.plumery.inventoryitem.api.resources.InventoryItemResource)

Swagger API

Download swagger ui from https://github.com/swagger-api/swagger-ui
Extract the zip
Change to dist folder
Open index.html
Point to:

http://localhost:9901/swagger.json

Replaying Projection

Download and unzip Kafka
Change to KAFKA_HOME
Stop API Micro-Service
Execute the following command:

./bin/kafka-streams-application-reset.sh --application-id InventoryItemsDenormalizationApplication \
                                      --input-topics InventoryItem \
                                      --bootstrap-servers localhost:9092 \
                                      --zookeeper localhost:2181

TODO

Get rid of ID.class
~~Generate all the events and commands from JSON schema~~
Implement UI Micro-Service

yesmukhamedoff / cqrs-eventsourcing-kafka