/spring-workshop-spring-cloud-gateway

Contains the assignment for the Spring Workshop on implementing an Edge Service using Spring Cloud Gateway

Primary LanguageJavaMIT LicenseMIT

Spring Workshop - Spring Cloud Gateway - Lab

This repository includes the lab assignment on implementing an edge service using Spring Cloud Gateway.

Getting Started

After introducing a discovery service into our system landscape and integrating it with our application services, we're now ready to move on to the next step. We'll extend our system landscape by adding another service that will act as a single, unified gateway to all of our application services and infrastructure components. Before we start though, we have to make sure that the baseline for this lab assignment builds and packages correctly into Docker images that we are able to run locally.

Building source code

The source material that we're working on comprises several Maven modules. Please make sure that everything compiles successfully. You'll find the top-level pom.xml at the root folder of the lab content. Issue a

$ mvn clean package

from within the root folder. This builds all the modules; the fat JARs for every module will be located at the target folder for each and every Maven module. Building the Docker images for our services relies on these JAR files, so make sure that you build the whole solution first before building the Docker images.

Building Docker images

The source material that you're given features a docker folder. You'll find all the scripts for the assignment in that folder. To make sure that you've got all the required Docker images present on your system, we recommend that you start up the baseline scenario. This can be done by issuing

Linux / MacOS

$ cd docker
$ ./build-containers.sh
$ docker-compose up

Windows

$ cd docker
$ build-containers.bat
$ docker-compose up

This will launch a service instance of the command service and the query service, which both expose a public HTTP API that you work with. It also launches a small Kafka cluster consisting of a single broker. This is a requirement for the interoperability between the command service and the query service. Don't worry too much about that Kafka cluster - it needs to be there, but we won't work with it.

Please make sure that both services launch correctly and respond with their public API.

  • The command service listens on port 8089.
  • The discovery service listens on port 8090.
  • The discovery service listens on port 8761.

All of these services expose their port through the host system and are thus available via localhost.

  • Click here for opening the OpenAPI UI for the command service.
  • Click here for opening the OpenAPI UI for the discovery service.
  • Click here for opening the dashboard of the Eureka Server

OpenAPI UI for Command Service

The API specification is minimalistic. Nevertheless, play around with the OpenAPI UI a bit to get a feel for what we'll be working on as part of the workshop.

If you have any questions or run into problems, please don't hesitate to ask for help.

Docker CLI Hints

Starting containers using docker-compose

$ docker-compose up

Stopping containers using docker-compose

$ docker-compose stop

Removing containers using docker-compose

$ docker-compose rm -f