GitHub - microservices-patterns/ftgo-application: Example code for the book Microservice patterns

Please note

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.

Got questions?

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

Application architecture

Service design

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

Chapter by chapter

This section maps the chapters to the code.

Chapter 3 Inter-process communication in a microservice architecture

The services have a REST API
The services also communicate using the Apache Kafka message broker via the Eventuate Tram framework

Chapter 7 Implementing queries in a microservice architecture

ftgo-order-history-service is an example of a CQRS view
ftgo-api-gateway uses API composition to implement the REST endpoint for retrieving the order history

Building and running the application

Pre-requisites

Java 8+
Docker and Docker Compose
Internet access so that Gradle and Docker can download dependencies and container images

Building

Temporary: Build the Spring Cloud Contracts using this command:

Build the services using this command:

Running the application

Run the application using this command:

Note: the ':'

This can take a while.

Stopping the application

Stop the application using this command:

Deploying the application on Kubernetes

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

You can run this command

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

Undeploying the services

You can run the script to undeploy the services:

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

If you want to delete the persistent volumes for Apache Kafka, Zookeeper and MySQL please run the command:

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

Setting environment variables to do development

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

A quick way to set the environment variables is to run the script ./set-env.sh.

Long way

The value of DOCKER_HOST_IP must be meaningful to both Java services/tests running on your desktop/laptop and to Docker containers. Please do NOT set it to the unresolvable hostname of your machine, localhost or 127.0.0.1 since the Docker containers will probably not work correctly.

Verifying that DOCKER_HOST_IP is set correctly

You can verify that DOCKER_HOST_IP is set correctly by running this command:

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

If you want to run Java services/tests within your IDE on your desktop/laptop AND the Docker containers are not accessible via localhost THEN you will need to set DOCKER_HOST_IP within your IDE. How to do this depends on your operating system and IDE. For example, I find it convenient to launch my IDE from the command line and after setting this environment variable.