This is the example code for my book Microservice patterns.

• The code is still work in progress

• It primarily illustrates the technical aspects of the microservice architecture and so the business logic is minimal

• The documentation is sparse/non-existent and you will need to look in the book

• The application consists of many services and so requires a lot of memory. It runs well, for example, on a 16GB Macbook pro.

• The application’s services and the infrastructure services, such as MySQL and Apache Kafka, are deployed using Docker containers using either Docker Compose or Kubernetes.

Please create a github issue and I’ll do my best to help you.

Not surprisingly, this application has a microservice architecture. There are the following services:

• ftgo-consumer-service - the Consumer Service

• ftgo-restaurant-service - the Restaurant Service

• ftgo-order-service - the Order Service

• ftgo-kitchen-service - the Kitchen Service

• ftgo-accounting-service - the Accounting Service

• ftgo-order-history-service - a Order History Service, which is a CQRS view

• ftgo-api-gateway - the API gateway

Key points:

• A service consists of a single Gradle module. For example, ftgo-order-service implements the Order Service

• A service is a Spring Boot application

• A service has a Swagger UI http://…​/swagger-ui.html. See open-swagger-uis.sh

• A service typically consists of the following packages:

  • domain - domain logic including aggregates

  • messaging - messaging adapters

  • web - Spring MVC controllers (HTTP adapters)

  • main - the main application

• The services use the following other frameworks

  • Eventuate Tram framework - implements transactional messaging

  • Eventuate Tram Saga framework - implements sagas

  • Eventuate Client framework - implements event sourcing

This section maps the chapters to the code.

Chapter 3 Inter-process communication in a microservice architecture

Chapter 4 Managing transactions with sagas

Chapter 5 Designing business logic in a microservice architecture

Chapter 6 Developing business logic with event sourcing

Chapter 7 Implementing queries in a microservice architecture

Chapter 8 External API patterns

Pre-requisites

Building

./gradlew buildContracts

./gradlew assemble

Running the application

./gradlew :composeUp

Using the application

Stopping the application

./gradlew :composeDown

You can find Kubernetes YAML files in the following directories: deployment/kubernetes and */src/deployment/kubernetes. There are also some helpful shell scripts.

Deploying services

./deployment/kubernetes/scripts/kubernetes-deploy-all.sh

Undeploying the services

./deployment/kubernetes/scripts/kubernetes-delete-all.sh

./deployment/kubernetes/scripts/kubernetes-delete-volumes.sh

You should not need to set any environment variables. To run the application, you certainly do not. Similarly, to do development (e.g. run tests), you typically do not need to set any environment variables. That’s because Docker containers are generally accessible (e.g. Docker for Windows/Mac) on the host via localhost. However, if Docker is running elsewhere (e.g. you are using Docker Toolbox) you will need to set DOCKER_HOST_IP.

Quick way

Long way

Verifying that DOCKER_HOST_IP is set correctly

docker run -p 8889:8888 -e DOCKER_DIAGNOSTICS_PORT=8889 -e DOCKER_HOST_IP \
     --rm eventuateio/eventuateio-docker-networking-diagnostics:0.2.0.RELEASE

Setting the environment variable in your IDE