Helidon Quickstart MP
Sample Helidon MP project that includes multiple REST operations.
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 pods # Wait for quickstart pod to be RUNNING
kubectl get service helidon-quickstart-mp # Verify deployed service
Note the PORTs. You can now exercise the application as you did before but use the second port number (the NodePort) instead of 8080.
After you’re done, cleanup.
kubectl delete -f app.yaml
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