🚀 Module: Quarkus Hello Country Service

Technology Stack:

• Knative
• Quarkus

---

🎯 Scenario

Quarkus REST application that mirrors the Node.js workshop service. It loads src/main/resources/data/greetings.json, reads the COUNTRY_CODE environment variable (default EN), and exposes a single GET / endpoint returning:

{
  "code": "EN",
  "message": "Hello World"
}

If the configured country code is unknown, the endpoint responds with 404 and { "error": "Unknown country code '<CODE>'" }.

---

✏️ Local Development

1. Start Quarkus dev mode:

./mvnw quarkus:dev

2. Override the greeting before launching dev mode (value is upper-cased automatically):

COUNTRY_CODE=FR ./mvnw quarkus:dev

3. Quarkus listens on http://localhost:8080 by default, or use PORT=<value> to override. Test the endpoint:

curl http://localhost:8080/

4. Run the tests:

./mvnw test

---

🔨 Container Build

Select the option that is most appropriate:

Generic Registry

Build a container image using the provided multi-stage Dockerfile (replace <REGISTRY>/<REPOSITORY> with your registry path):

IMAGE=<REGISTRY>/<REPOSITORY>/hello-country-service:latest
podman build -t "$IMAGE" .
# or: docker build -t "$IMAGE" .

podman push "$IMAGE"
# or: docker push "$IMAGE"

The resulting image runs on UBI OpenJDK 21 and exposes port 8080.

---

OpenShift Local Registry (external route)

oc project <NAMESPACE>
REGISTRY=$(oc registry info)
podman login -u "$(oc whoami)" -p "$(oc whoami -t)" "$REGISTRY"
IMAGE=${REGISTRY}/<NAMESPACE>/hello-country-service:latest
podman build -t "$IMAGE" .
podman push "$IMAGE"

---

Build Inside OpenShift (BuildConfig)

# Point to the project that should own the image
oc project <NAMESPACE>

# Create a Docker strategy BuildConfig (run once)
oc new-build --strategy=docker --binary --name hello-country-service

# Start a build using the local working tree and stream logs
oc start-build hello-country-service --from-dir=. --follow

# Verify the resulting image stream tag
oc get is hello-country-service -n <NAMESPACE>

The successful build publishes the image at:

image-registry.openshift-image-registry.svc:5000/<NAMESPACE>/hello-country-service:latest

---

🚢 Deploy to Knative

1. Update knative-service.yaml with your image reference (for OpenShift local registry, set your-namespace accordingly), then apply it:

oc apply -f knative-service.yaml -n <NAMESPACE>

2. Knative injects a PORT environment variable automatically; do not set one in the manifest. Override the greeting via COUNTRY_CODE.

Or, using the Knative CLI without modifying the YAML:

IMAGE=image-registry.openshift-image-registry.svc:5000/<NAMESPACE>/hello-country-service:latest

kn service apply hello-country-service \
  --image "$IMAGE" \
  --env COUNTRY_CODE=EN

3. Retrieve the URL:

kn service describe hello-country-service -o url

4. Test the service once it is ready:

curl "$(kn service describe hello-country-service -o url)"

5. To update the greeting later, patch the service:

kn service update hello-country-service --env COUNTRY_CODE=FR