🚀 Module: Node.js Hello Country Service

Technology Stack:

• Knative
• Node.js

---

🎯 Scenario

Simple Express service that returns a phonetic "Hello World" greeting for a configured country code. The app loads configuration from environment variables (via dotenv for local development) and supports deployment to Knative.

---

✏️ Local Development

1. Run the application

npm install
npm run dev

2. Set the greeting by updating .env or exporting variables before running:

export COUNTRY_CODE=GA
export PORT=3000
npm start

---

🔨 Container Build

Select the option that is most appropriate:

Generic Registry

# Replace <registry>/<repo> with your container 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"

---

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