README.md

Overview

This sample demonstrates how to build and deploy a Micronaut microservice as an extension and expose the API in SAP Cloud Platform, Kyma runtime.

Micronaut enables creating native images using GraalVM for Java.

This sample demonstrates how to:

• Create a development Namespace in the Kyma runtime.
• Create and deploy a Micronaut application in the Kyma runtime.
• Expose the application using APIRules.
• Explore the APIs.

Prerequisites

• SAP Cloud Platform, Kyma runtime instance
• Docker
• make
• Gradle
• kubectl configured to use the KUBECONFIG file downloaded from the Kyma runtime
• Java 8+

Application

The Micronaut application implements a simple Orders API with CRUD operations.

Steps

Prepare for deployment

• Create a new dev Namespace:

kubectl create namespace dev

• Build and push the image to the Docker repository:

DOCKER_ACCOUNT={your-docker-account} make push-image

Kubernetes Deployment

This section details out deploying the extension using standard Kubernetes resources.

To deploy as Helm chart, please refer to Helm Chart Deployment

• Update the image name in the Kubernetes Deployment. Refer to the standard Kubernetes Deployment and Service definitions.

• Deploy the application:

kubectl -n dev apply -f ./k8s/deployment.yaml

• Verify that the Pods are up and running:

kubectl -n dev get po

The expected result shows that the Pod for the sample-extension-micronaut Deployment is running:

Expose the API

• Create an APIRule. In the APIRule, specify the Kubernetes Service that is exposed:

apiVersion: gateway.kyma-project.io/v1alpha1
kind: APIRule
metadata:
  name: sample-extension-micronaut
spec:
  gateway: kyma-gateway.kyma-system.svc.cluster.local
  rules:
    - accessStrategies:
        - config: {}
          handler: noop
      methods:
        - GET
        - POST
        - PUT
        - DELETE
      path: /.*
  service:
    host: sample-extension-micronaut
    name: sample-extension-micronaut
    port: 8080

This sample snippet exposes the sample-extension-micronaut Service. The Service is specified in the spec.service.name field. The sample-extension-micronaut subdomain is specified in the spec.service.host field.

• Apply the APIRule:

kubectl -n dev apply -f ./k8s/api-rule.yaml

Helm Chart Deployment

A Helm Chart definition is also available for developers to try out.

Must Haves

• kubectl
• Helm3

Helm install

To install the helm chart in dev namespace, run the following command. Change to use your image. You can also override other parameters defined in values.yaml

helm -n dev install kymaapp ../helm-charts/sample-extension-micronaut --set image.repository=gabbi/sample-extension-micronaut:0.0.7 --set jdbc.user={db user} --set jdbc.password={db password}

To verify, the installed chart, run helm -n dev ls

Try it out

Access the APIs through this URL: <https://sample-extension-micronaut.{cluster domain}/orders>

Try out various APIs.