Helidon Quickstart MP Example

This example implements a simple Hello World REST service using MicroProfile

Prerequisites

1. Maven 3.5 or newer
2. Java SE 8 or newer
3. Docker 17 or newer (if you want to build and run docker images)
4. Kubernetes minikube v0.24 or newer (if you want to deploy to Kubernetes) or access to a Kubernetes 1.7.4 or newer cluster
5. Kubectl 1.7.4 or newer for deploying to Kubernetes

Verify prerequisites

java -version
mvn --version
docker --version
minikube version
kubectl version --short

Build

mvn package

Start the application

java -jar target/HelloWorldMP.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 HelloWorldMP .

Start the application with Docker

docker run --rm -p 8080:8080 HelloWorldMP: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 HelloWorldMP  # Verify deployed service