tomas-langer / helidon-hol-example

This is a Helidon application providing "health" endpoint for pets

Helidon Quickstart MP

Helidon MP project for HOL.

Build and run

With JDK11+

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

Exercise the application

curl -X GET http://localhost:8081/vaccinated/Dino
true

curl -X GET http://localhost:8081/vaccinated/GoodBoy
false

Try health and metrics

curl -s http://localhost:8081/health
{"outcome":"UP",...
. . .

# Prometheus Format
curl -s http://localhost:8081/metrics
# TYPE base:gc_g1_young_generation_count gauge
. . .

# JSON Format
curl -H 'Accept: application/json' http://localhost:8081/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 native image with GraalVM

GraalVM allows you to compile your programs ahead-of-time into a native executable. See https://www.graalvm.org/docs/reference-manual/aot-compilation/ for more information.

You can build a native executable in 2 different ways:

• With a local installation of GraalVM
• Using Docker

Local build

Download Graal VM at https://www.graalvm.org/downloads, the version currently supported for Helidon is 20.1.0.

# Setup the environment
export GRAALVM_HOME=/path
# build the native executable
mvn package -Pnative-image

You can also put the Graal VM bin directory in your PATH, or pass -DgraalVMHome=/path to the Maven command.

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

Start the application:

./target/helidon-quickstart-mp

Multi-stage Docker build

Build the "native" Docker Image

docker build -t helidon-quickstart-mp-native -f Dockerfile.native .

Start the application:

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

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-mp/bin/start

Multi-stage Docker build

Build the "jlink" Docker Image

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

Start the application:

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

See the start script help:

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