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 theEventuate Tram framework

Chapter 4 Managing transactions with sagas

Theftgo-order-service uses sagas to maintain data consistency:

• CreateOrderSaga

• CancelOrderSaga

• ReviseOrderSaga

The services that participate in these sagas define the following command handlers:

• Accounting ServiceAccountingServiceCommandHandler

• Consumer ServiceConsumerServiceCommandHandlers

• Kitchen ServiceKitchenServiceCommandHandler

• Order ServiceOrderCommandHandlers

Chapter 5 Designing business logic in a microservice architecture

All the services' business logic is implemented using Domain-Driven design aggregates.

• Accounting Service

  • Account aggregate in theftgo-accounting-service

• Consumer Service

  • Consumer

• Order Service

  • Order

  • Restaurant

• Kitchen Service

  • Restaurant

  • Ticket

• Restaurant Service

  • Restaurant

Chapter 6 Developing business logic with event sourcing

• TheAccount aggregate in theftgo-accounting-service is implemented using event sourcing

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

Chapter 8 External API patterns

• ftgo-api-gateway is the API gateway

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.

Using the application

Use the services Swagger UIs to invoke the services.

• Create consumer -http://localhost:8081/swagger-ui/index.html

• Create a restaurant -http://localhost:8084/swagger-ui/index.html

• Create an order -http://localhost:8082/swagger-ui/index.html

• View the order -http://localhost:8082/swagger-ui/index.html

• View the order history -http://localhost:8086/swagger-ui/index.html

You can also access the application via theAPI Gateway athttp://localhost:8087.However, currently it doesn’t have a Swagger UI so you will have to usecurl, for example.

Note: if the containers aren’t accessible vialocalhost - e.g. you are using Docker Toolbox, you will have to use${DOCKER_HOST_IP} as described below.

Stopping the application

Stop the application using this command:

Deploying services

You can run this command

Undeploying the services

You can run the script to undeploy the services:

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

Quick way

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

Long way

The value ofDOCKER_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 or127.0.0.1 since the Docker containers will probably not work correctly.

Verifying that DOCKER_HOST_IP is set correctly

You can verify thatDOCKER_HOST_IP is set correctly by running this command:

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 vialocalhost THEN you will need to setDOCKER_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.