Tag: event sourcing

Introducing the Eventuate Local Console

We are super excited to announce that the Eventuate Local event store now has a simple console. It lets you browse the aggregate types and view aggregate instances. You can also see  a real-time view of the events as they are saved in the event store.

Here is a screenshot showing the TodoAggregate instances:

aggregateinstances

Here is a screenshot showing recent events:

aggregateevents

The UI is implemented using ReactJS UI and a NodeJS-based server. It is packaged as a Docker container image and can be run by defining the following container in your project’s docker-compose.yml:

consoleserver:
 image: eventuateio/eventuateio-local-console:0.12.0
 links:
 - mysql
 - zookeeper
 ports:
 - "8085:8080"
 environment:
 SPRING_DATASOURCE_URL: jdbc:mysql://mysql/eventuate
 SPRING_DATASOURCE_USERNAME: mysqluser
 SPRING_DATASOURCE_PASSWORD: mysqlpw
 EVENTUATELOCAL_ZOOKEEPER_CONNECTION_STRING: zookeeper:2181

Run the Eventuate Todo example application to see it in action.

JavaOne 2016: Handling Eventual Consistency in JVM Microservices with Event Sourcing

Last week at JavaOne 2016, Chris Richardson, founder of Eventuate, Inc, and Kenny Bastani, developer advocate at Pivotal, gave a talk on using Event Sourcing to maintain data consistency in a microservices architecture.

Example code

Here is the code for the sample Spring Boot application that Kenny developed for the talk. What is especially exciting is that the microservices demo is built using Eventuate!

Slides

Here are the slides:

Learn more about Eventuate

To find out more about Eventuate:

 

Developing microservices with #DDD aggregates (SpringOne platform, #s1p)

Last week at Spring One Platform, our founder Chris Richardson gave a talk on developing microservices with Domain-Driven Design aggregates.

 

Slides

Here are the slides:

Example code

Here is the code for the Orders and Customers example.

Learn more about Eventuate

To find out more about Eventuate:

Microservices and Redis – a keynote at #redisconf

Yesterday, Chris Richardson, the founder of Eventuate, gave a keynote about microservices and Redis at RedisConf 2016. Chris described the microservices architecture, explained why you should use it and discussed where Redis fits in.

Slides

Here are the slides:

Example code

There is also an sample application consists of event-driven microservices built using event sourcing and CQRS that uses Redis as a CQRS view.

Learn more about Eventuate

To find out more about Eventuate:

 

Real-time, collaborative Kanban board example built with event sourcing, microservices, @springboot and @docker

We are super excited about the latest Eventuate sample application. It is a real-time, collaborative Kanban board. The application uses Websockets to deliver events published by the Eventuate event store to each user’s browser. This ensures that every user viewing a Kanban board sees the same consistent view . It is a great example of how event sourcing is an excellent choice for real-time collaborative applications.

The following diagram shows the architecture.

The application has an AngularJS front-end. Each of the microservices as well as the API Gateway are written in Java and use Spring Boot. The system-of-record is the Eventuate event store. MongoDB is used as a CQRS view of boards and tasks. The microservices , the API gateway and MongoDB are deployed using Docker.

Event sourcing is a good choice for this kind of collaborative application. That is because whenever the state of the application – i.e. a board or a task – changes an event is published. Those events can then update the information displayed to the users. In this application the events are transformed into WebSocket messages and delivered each user’s browser.

Learn more about Eventuate

To find out more about Eventuate:

 

The Eventuate Todo List application: #microservices, @SpringBoot, #EventSourcing, #CQRS

It is a challenge to write a simple yet meaningful example application that illustrates how to develop event-driven microservices using the Eventuate platform. That is because the microservices architecture requires you to have at least two services. The Money Transfer application has, for example, three (soon to be at least 4) separate services. Even though it is a great example of how to write event-driven microservices using event sourcing and CQRS it is not the easiest introduction to the topic.

To make the getting started experience easier we have created the Todo List application. This application is a Java and Spring Boot application built using Eventuate™’s Event Sourcing based programming model. The application has a HATEAOS-style REST API for creating, querying, updating and deleting a todo list. The API design is inspired by the Todo backend project. The principle difference is that unlike the original version this API is eventually consistent.

The application has a CQRS-based architecture. Creates, updates and deletes are handled by the command side service, which consists of a Todo Aggregate that is persisted using event sourcing. Queries are handled by the query side service, which maintains a materialized view of the todo list in a SQL database.

There are two versions of the application. The simplest version is a single module Gradle project that builds monolithic version of the application of the API. It is a great way to learn the Eventuate API.

The other version of the application is a multi-module Gradle project, which can be deployed as either a monolith or as two microservices: a command-side service and a query-side service.

Both versions come with a Docker Compose file that can be used to launch the application along with a MySQL database.

To get started take a look at the README.md.

Learn more about Eventuate

To find out more about how you can use the Eventuate platform to build event-driven microservices:

#hacksummit 2016 – event-driven microservices – Events on the outside, on the inside and at the core

A couple of days ago at the virtual conference Hacksummit 2016, Chris Richardson, the founder of Eventuate, gave a talk on event-driven microservices. Here is the abstract:

This presentation looks at the importance of events and the role that they play in applications. We describe how events are a key application integration mechanism and how they are used by applications to communicate with the outside world. You will learn how the microservices inside a system can use events to maintain data consistency. We discuss how easy it is to implement both of these mechanisms by developing your core business logic using an event-centric approach known as event sourcing.

The talk describes how to build event-centric business logic using event sourcing. The events emitted by DDD aggregates are used within an application to maintain data consistency across services. They are also used to integrate applications using the patterns of enterprise integration. Events are used to generate notifications (SMS, email, mobile push etc) that are sent to users.

Here are the slides:

And, here is the video

Learn more about Eventuate

To find out more about how you can use the Eventuate platform to build event-driven microservices:

Presentation on event-driven microservices – Events on the outside, on the inside and at the core

A couple of weeks ago at JFokus 2016, Chris Richardson, the founder of Eventuate, gave a talk on event-driven microservices. Here is the abstract:

This presentation looks at the importance of events and the role that they play in applications. We describe how events are a key application integration mechanism and how they are used by applications to communicate with the outside world. You will learn how the microservices inside a system can use events to maintain data consistency. We discuss how easy it is to implement both of these mechanisms by developing your core business logic using an event-centric approach known as event sourcing.

The talk describes how to build event-centric business logic using event sourcing. The events emitted by DDD aggregates are used within an application to maintain data consistency across services. They are also used to integrate applications using the patterns of enterprise integration. Events are used to generate notifications (SMS, email, mobile push etc) that are sent to users.

Here are the slides:

Learn more about Eventuate

To find out more about how you can use the Eventuate platform to build event-driven microservices: