jorgemoralespou/lab-spring-boot

Eduk8s lab for Spring Boot

LAB - Spring Boot

Sample workshop for Spring Boot app deployment

Tooling Setup

Currently eduk8s workshop dashboard is setup in a single container where resources such as Theia IDE, Terminal etc are placed in their corresponding specific folders under /opt/. Then the start-container script of the Workshop Dashboard starts Theia IDE, Terminal and other parts of the dashboard including other special resources start up scripts that Workshop Dashboard looks for at special locations. (See https://github.com/eduk8s/workshop-dashboard/blob/develop/dashboard/usr/bin/start-container#L106).

Therefore the trick is to override or provide something extra would be store or overwrite the app in a specific folder and then provide the start up shell script for it.

Initializr

The Spring Initializr app has been modified to generate the project at a specific location locally: /generate end point. The Web UI has been changed accordingly to call /generate end point when Generate button is clicked. The location to store the generated project is to be specified via the property initializr.initializr.project-location-container.

• The backend for the modified Spring Initializr - initializr: https://github.com/BoykoAlex/initializr branch: eduk8s
• The front end serving piece of the modified Initializr - start.spring.io: https://github.com/BoykoAlex/start.spring.io branch eduk8s (Build instructions: build initializr first ./mvnw clean install -DskipTests and then start.spring.io with the same command. Then start.spring.io/start-site/target/start-site-exec.jar is the fat JAR for the Initializr app)

The docker image file for the modified Initializr: https://github.com/BoykoAlex/start.spring.io/blob/eduk8s/start-site/Dockerfile The published Docker image: boykoalex/eduk8s-initializr-test

Hook up Initializr to eduk8s

The Dockerfile copies initializr.jar from boykoalex/eduk8s-initializr-test Docker image into workshop's Docker image at /opt/initializr/initializr.jar. The Dockerfile also copies initializr/start-initializr.shscript that fires up the Initializr app inside the container into /opt/eduk8s/etc/setup.d/start-initializr.sh which is one of the locations being scanned by workshops container start script for various scripts to execute. The Initializr start script starts Initialiazr app on a specific port (10189 currently) and sets the folder to store generated projects to be /home/eduk8s which is the landing location for all workshop session resources for a user.

Now Initializr needs to be integrated into Workshop Dashboard similarly to Theia and other UI bits. Outside traffic needs to be directed to Initializr app running on its port (10189). This can be done in resources/workshop.yaml file under session:

    ingresses:
    - name: initializr
      port: 10189

(See for more details eduk8s documentation: https://docs.eduk8s.io/en/latest/runtime-environment/workshop-definition.html#defining-additional-ingress-points)

Once traffic redirection has been setup with the help of the ingress setting above the UI can be tweaked to show Initializr UI.

The tab similar to Theia IDE can be setup easily via a small change in resources/workshop.yaml file under session:

    dashboards:
    - name: initializr
      url: "$(ingress_protocol)://$(session_namespace)-initializr.$(ingress_domain)/"      

(See for more details eduk8s documentation: https://docs.eduk8s.io/en/latest/runtime-environment/workshop-definition.html#adding-custom-dashboard-tabs)

Lastly, one can even embedd the Initializr UI into workshop content Markdown pages with an iframe element:

<iframe style="width:100%;height:900px" src="${INGRESS_PROTOCOL}://${SESSION_NAMESPACE}-initializr.${INGRESS_DOMAIN}/"></iframe>

The trick here is that variables in the URL need to be substituted at the session deployment time by a script that would be executed at the session container start up time. The example script is kept in workshop/setup.d/create-resources.sh. It takes workshop/content/exercises/step.md.in file and substitutes the variables with the values of corresponding environment variables and stores the result in step2.md file. Note that the whole workshop folder is placed in the container such that the create-resources.sh is executed at the startup time and no further work is required in the Dockefile

Theia IDE with Java and Spring Boot Extensions

Currently Theia IDE in eduk8s is setup with

1. package.json file located in the container at /opt/theia/package.json
2. The Workshop Dashboard Dockerfile building Theia executing yarn command
3. Theia IDE is started with the shell script: https://github.com/eduk8s/workshop-dashboard/blob/develop/dashboard/opt/eduk8s/sbin/start-theia placed at /opt/eduk8s/sbin/start-theia The package.json has just a few extensions and no directory specified for picking up extra extensions as .vsix files.

Current state of Theia IDE implies two ways to have Java and Spring Boot extensions:

1. Overwrite package.json file in the container with our own contant that includes extensions for Java and Spring Boot. then re-run Theia build
2. Wipe out /opt/theia folder entirely and copy there Theia IDE from our STS4 Theia Docker image kdvolder/sts4-theia-snapshot:stable