Helidon Quickstart MP Example

This example implements a simple Hello World REST service using MicroProfile.

Build and run

With JDK11+

mvn package
java -jar target/helidon-quickstart-mp.jar

Exercise the application

curl -X GET http://localhost:8080/greet
{"message":"Hello World!"}

curl -X GET http://localhost:8080/greet/Joe
{"message":"Hello Joe!"}

curl -X PUT -H "Content-Type: application/json" -d '{"greeting" : "Hola"}' http://localhost:8080/greet/greeting

curl -X GET http://localhost:8080/greet/Jose
{"message":"Hola Jose!"}

Try health and metrics

curl -s -X GET http://localhost:8080/health
{"outcome":"UP",...
. . .

# Prometheus Format
curl -s -X GET http://localhost:8080/metrics
# TYPE base:gc_g1_young_generation_count gauge
. . .

# JSON Format
curl -H 'Accept: application/json' -X GET http://localhost:8080/metrics
{"base":...
. . .

Build the Docker Image

docker build -t helidon-quickstart-mp .

Start the application with Docker

docker run --rm -p 8080:8080 helidon-quickstart-mp:latest

Exercise the application as described above

Deploy the application to Kubernetes

kubectl cluster-info                         # Verify which cluster
kubectl get pods                             # Verify connectivity to cluster
kubectl create -f app.yaml               # Deploy application
kubectl get service helidon-quickstart-mp  # Verify deployed service

Build a Java Runtime Image using jlink

You can build a custom Java Runtime Image (JRI) containing the application jars and the JDK modules on which they depend. This image also:

• Enables Class Data Sharing by default to reduce startup time.
• Contains a customized start script to simplify CDS usage and support debug and test modes.

You can build a custom JRI in two different ways:

• Local
• Using Docker

Local build

# build the JRI
mvn package -Pjlink-image

See https://github.com/oracle/helidon-build-tools/tree/master/helidon-maven-plugin#goal-jlink-image for more information.

Start the application:

./target/helidon-quickstart-se/bin/start

Multi-stage Docker build

Build the "jlink" Docker Image

docker build -t helidon-quickstart-se-jlink -f Dockerfile.jlink .

Start the application:

docker run --rm -p 8080:8080 helidon-quickstart-se-jlink:latest

See the start script help:

docker run --rm helidon-quickstart-se-jlink:latest --help