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Todo List example application

The Todo List application is the hello world application for the Eventuate™ event sourcing. It illustrates how you can use the platform to write an application with a microservices architecture that uses Event Sourcing and Command Query Responsibility Segregation (CQRS). The Todo List application lets users maintain a todo list.

The Todo List application is a Java and Spring Boot application built using Eventuate™'s Event Sourcing based programming model. Todos are implemented by an Event Sourcing-based TodoAggregate. The aggregate's events are persisted in the Eventuate event store. The application also maintains a materialized view of the data in MySQL.

Don't forget to take a look at the other Eventuate example applications.

Got questions?

Don't hesitate to create an issue or see


The Todo application has a microservice architecture. It is written using the Eventuate Client Framework for Java, which provides an event sourcing based programming model. The following diagram shows the Todo List application architecture:

The application consists of the following:

  • Todo service - a Java and Spring Boot-based service that has a HATEOAS-style REST API for creating, updating and querying todo list items. It uses Eventuate to persist aggregates using event sourcing.
  • Todo view service - a Java and Spring Boot-based service that provides a REST API for querying todos. It implements a Command Query Responsibility Segregation (CQRS) view of todos using MySQL. MySQL is kept up to date by subscribing to events produced by the Todo service.
  • MySQL database - stores the CQRS view of todo list items.

Note: for simplicity, the Todo list application can be deployed as a monolithic application.

Building and running the application

First, build the application

./gradlew assemble

Next, launch the services using Docker Compose:

export DOCKER_HOST_IP=...
./gradlew <database-mode>ComposeBuild
./gradlew <database-mode>ComposeUp

Where database-mode is one of:

  • mysqlbinlog - use MySQL with Binlog-based event publishing
  • postgreswal - use Postgres with Postgres WAL-based event publishing
  • postgrespolling - use Postgres with generic JDBC polling-based event publishing

Note: You need to set DOCKER_HOST_IP before running Docker Compose. This must be an IP address or resolvable hostname. It cannot be localhost. See this guide to setting DOCKER_HOST_IP for more information.

Using the application

Once the application has started, you can use the application via the Swagger UI.

  • http://${DOCKER_HOST_IP}:8081/swagger-ui.html - the command-side service
  • http://${DOCKER_HOST_IP}:8082/swagger-ui.html - the query-side service

Got questions?

Don't hesitate to create an issue or see


A Java and Spring Boot Todo list application built using Eventuate







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