Spring Boot Scala Example

This is an example Spring Boot app using Scala.

Docker run:

docker run -p 8080:8080 jecklgamis/spring-boot-scala-example:main

What's In the Box?

• Scala 3
• Maven and SBT build
• Ubuntu Docker image
• Jetty web container
• HTTPS listener (prod profile) using self-signed certs
• JUnit5 tests
• Actuator endpoints (health, metrics)
• Build info, liveness and readiness probe endpoints
• Example Kubernetes deployment

This is a Github Template project. You can create a copy of this project from a clean slate. Simply click Use this template button.

Building

Ensure you have Java 21, Docker, and Make installed.

make all

This will create build info, keystore, executable jar, and Docker image in one go. Explore the Makefile for details.

Running

Run using Docker:

make run

Run using executable jar:

java -jar target/spring-boot-scala-example.jar

Endpoints

Point your browser to the urls below or use curl in command line.

curl http://localhost:8080/
curl http://localhost:8080/buildInfo
curl http://localhost:8080/probe/live
curl http://localhost:8080/probe/ready
curl http://localhost:8080/actuator/metrics
curl http://localhost:8080/actuator/health

or you can run ./smoke-tests.sh

Building With SBT

Ensure you have SBT installed.

Mac OS:

brew install sbt

Build executable jar:

sbt assembly

Run main class:

sbt run

To build interactively, enter the SBT shell by typing sbt. You should then be able to compile, test, assemble, or run any other sbt commands.

Deploying To Kubernetes

Assumptions:

• You have helmcommand installed (Mac OS: brew install helm)
• You can deploy to a Kubernetes cluster that can access Docker Hub

Build and install Helm chart:

cd deployment/k8s/helm
make install 

This creates:

• a service account
• a pod running on port 8080
• a service listening on port 80 (and implicitly endpoint resources corresponding to the number of pods)
• a deployment (and implicitly replicaset)
• an ingress for Istio (change kubernetes.io/ingress.class if you're using a different ingress controller such as nginx)

To connect to the app locally, create a tunnel to the service:

kubectl port-forward service/spring-boot-scala-example 18080:80
curl http://localhost:18080

If you have ingress controller installed in your cluster, you can connect using

curl -v -H "Host:spring-boot-scala-example.local" http://<your-ingress-load-balancer-hostname>

Contributing

Please raise issue or pull request! Thanks!