In a browser window, navigate to the console of the lab OpenShift cluster at console. Login with your username and password (%USERID%/openshift). Open the Developer perspective in the globex-%USERID% namespace.

In the Developer perspective, open the Topology view. Expect to see something like this (rearrange the topology as you see fit):

Open the Globex UI application in a browser tab. To do so, click on the icon next to the blue circle representing the globex-ui deployment in the Topology view.

Click on Cool Stuff Store in the top menu to see a paginated list of products:

The Featured pane on the home page is empty at the moment. Also the product list page has an empty bar above the product list. These elements will be populated once the recommendation engine is up and running.

On the OpenShift console, click on the icon in the top menu on the right. This opens an editor where you can enter a Kubernetes resource definition in YAML or JSON format.

Paste the following KafkaTopic Custom Resource in the editor.

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaTopic
metadata:
  labels:
    strimzi.io/cluster: kafka
  name: globex.tracking
  namespace: globex-%USERID%
spec:
  topicName: globex.tracking
  partitions: 1
  replicas: 2
  config: {}

The Kafdrop UI can be used to verify that the topic has been correctly created. In the Topology view of the globex-%USERID% namespace, click on the icon next to the blue circle representing the kafdrop deployment.

This redirects you to the Kafdrop home page. Scroll down to see the list of topics. Expect to see the globex.tracking topics, which you just created.

As part of the provisioning of the Kafka broker, a secret kafka-client-secret was created in the globex-%USERID% namespace. To view the contents of the secret, click on Secrets in the left menu of the Developer perspective. Make sure you are pointing to the globex-%USERID% namespace.

In the list of secrets, locate the kafka-client-secret secret, and click on the name of the secret to open the secret details. Click on Reveal values to see the actual values stored in the secret.

To bind the Activity Tracking service and Recommendation Engine applications to the Kafka broker, create a ServiceBinding Custom Resource.

apiVersion: binding.operators.coreos.com/v1alpha1
kind: ServiceBinding
metadata:
  name: kafka-servicebinding
  namespace: globex-%USERID%
spec:
  application:
    group: apps
    labelSelector:
      matchLabels:
        service-binding/type: kafka
    resource: deployments
    version: v1
  bindAsFiles: true
  services:
    - group: ''
      kind: Secret
      name: kafka-client-secret
      version: v1

Once the service binding is done, the status of the ServiceBinding Custom Resource moves to Connected.

To check the injection of the secret by the Service Binding operator, navigate to the Topology view of the OpenShift console at OpenShift Console. Click on the activity-tracking deployment to open the details pane, and click on the deployment name (above the Details, Resources and Observe tabs) to open the full details of the Deployment.

Scale the activity-tracking deployment to 1 replica. You can do so by clicking on the activity-tracking deployment in the Topology view, and in the details window select the Details tab, and click the arrow next to the circle to scale the deployment.

Check the logs of the activity-tracking pod, and notice that the pod successfully connects to the Kafka broker instance.
To see the logs, click the Resources tab of the deployment, and click on the View logs link.

[...]
2023-06-13 10:00:31,873 INFO [io.sma.rea.mes.kafka] (main) SRMSG18258: Kafka producer kafka-producer-tracking-event, connected to Kafka brokers 'kafka-kafka-bootstrap.globex-user1.svc.cluster.local:9092', is configured to write records to 'globex.tracking'
2023-06-13 10:00:33,968 INFO [io.quarkus] (main) activity-tracking-service 1.0.0-SNAPSHOT on JVM (powered by Quarkus 2.7.4.Final) started in 13.993s. Listening on: http://0.0.0.0:8080
2023-06-13 10:00:33,969 INFO [io.quarkus] (main) Profile prod activated.
2023-06-13 10:00:33,969 INFO [io.quarkus] (main) Installed features: [cdi, kafka-client, resteasy-reactive, smallrye-context-propagation, smallrye-health, smallrye-reactive-messaging, smallrye-reactive-messaging-kafka, vertx]

Go back to the Topology view, and scale up the recommendation-engine deployment to 1 pod.

Once the recommendation-engine is up and running, check in the Kafdrop UI at kafdrop that a number of new topics have been created:

In a browser window, navigate to the Topology view of the lab’s OpenShift cluster at OpenShift Console.

Open the URL to the activity-tracking-simulator application by clicking the icon next to the blue circle representing the activity-tracking-simulator deployment.

This opens a Swagger UI page which allows you to use the REST API of the application. The REST application has only one operation, POST /simulate.

Generate a number of activity events. Click the Try it out button, and set count to any value between 100 and 1000. Click Execute.

You can use the Kafdrop UI to inspect the messages sent to the globex.tracking topic of the Kafka broker.
Navigate to the Kafdrop UI at kafdrop and click on the globex-tracking topic in the topic list. Notice the activity event messages produced by the Activity Tracking service:

The featured product list calculated by the Recommendation Engine is produced to the globex.recommendation-product-score-aggregated-changelog topic. The list is recalculated roughly every 10 seconds as long as activity events are produced. Every calculation produces a message to the changelog topic. The last message in the topic represents the latest top featured list.

In a browser window, navigate to the home page of the Globex Coolstuff web application. Notice that the home page now shows a list of featured products.