Introduction to the Workshop

This chapter explains the technical and functional environment for this workshop.

Let’s first introduce Globex, our fictitious company.

Globex is a fictitious company, active in different domains, including retail. The company recently started a digital transformation and cloud adoption journey to modernize its IT landscape. As part of this initiative, the development teams adopted new ways of working, and started the modernization of the legacy multi-tier monolithic retail e-commerce web application. As part of this modernization, the retail application was redeveloped using a modular approach on top of Quarkus, a modern cloud-ready Java runtime and a separate UI layer built using a state-of-the-art web development framework. The security of the application was improved with the introduction of OpenID Connect and Red Hat build of Keycloak. The application was containerized and re-hosted on OpenShift. As part of the modernization effort, the development and operation teams adopted DevOps and GitOps principles for rapid and continuous deployment.

The outcome of this application modernization effort is an increased velocity of application development and deployment, and an overall faster go to market for new functionalities.

A schematic overview of the state of the application after the first phase of the application modernization effort:

Taking advantage of this new momentum, the business quickly came up with new requirements for the e-commerce application. One of these requirements is the ability to track user-activity on the web site of the application, and generate product recommendations based on user activity. To achieve this, a streaming platform, Apache Kafka, was introduced to the architecture to generate a stream of user activity events from the web application. User activity events are generated in the web front-end application and forwarded to a new microservice using a REST API. The new service transforms and forwards the events to the streaming platform. The stream of user activity events is processed in real-time using a stream processing library to generate a list of featured products that can be highlighted on the web site.

The current architecture of the Globex retail web application:

Technical environment

OpenShift cluster: all the activities for this workshop will be done on a shared OpenShift cluster.
The connection details for the OpenShift cluster:
- OpenShift Console: {openshift_cluster_console}[{openshift_cluster_console}, window="_console"]
- Username: {user_name}
- Password: {user_password}
Depending on the workshop modules you will be guided through, there are helper components such as AMQ streams console, an integrated development environment (IDE) called OpenShift Dev Spaces, based on Eclipse Che and some more. All of these (including the IDE) are hosted on OpenShift, so the login to your OpenShift Console is the central entrypoint for your Developer Experience.
These additional components will be introduced in the following chapters and workshop modules, where applicable.
We leverage OpenShift Gitops (aka ArgoCD) to manage the deployment of the workshop assets, in a hub and spoke model: a central ArgoCD instance which manages common assets and namespace-scoped ArgoCD instances which manage the per-user assets. In total ArgoCD manages 350 applications per cluster, which represent more than 2500 pods and numerous secrets, configmaps and so on.
If you are interested to know more about this setup, click on the link below, or come to talk to the workshop instructors.
Click for details on the OpenShift Gitops setup
As mentioned before, we use a hub and spoke model to manage the workshop assets. A cluster-wide ArgoCD instance manages a number of namespace scoped ArgoCD instances (1 per workshop user). These namespace scoped ArgoCD instances manage the workshop assets for a user.

You can log into your namespace scoped ArgoCD instance and have a look at the assets managed by the instance:
- Navigate to ArgoCD. Expect to see the landing page of ArgoCD.
- Click on the Log in via OpenShift link, and log in with your OpenShift credentials ({user_name}/{user_password}).
- If this is the first time you access the ArgoCD console, you have to authorize ArgoCD to access your account. In the Authorize Access window click on Allow selected permissions.
- You are redirected to the application overview page of ArgoCD, which shows you all the applications that this instance of ArgoCD is managing. In ArgoCD language, an application represents a collection of Kubernetes/OpenShift resources that are managed as a whole.
  
  The list of applications managed by the ArgoCD instance depends on which modules you have deployed.
- If you click on one of the application cards, you’ll see an overview of all the Kubernetes resources managed as part of the application. This is for example an partial view of the Globex application:
- The way ArgoCD works is that the desired state of an application is described in a manifest, which is hosted in a version control system. ArgoCD makes sure that the deployed state of the application matches the desired state as described in the manifest. Changes in the manifest (a new commit for example) are picked up by ArgoCD and applied. Hence the name GitOps, which itself is an evolution of Infrastructure as code.
  ArgoCD manifests can take many forms. For this workshop we opted for Helm charts. You can find the Helm charts for this workshop here.

Walkthrough of the Globex web application

While the Globex web application used in this workshop is a demo app and as such does not pretend to be a real-life retail application, it packs enough functionality to make it feel like a real retail web app.

In this section of the workshop, you will explore the Globex web application, both from a deployment as well as a functional point of view.

On your workstation, navigate to {openshift_cluster_console}[OpenShift Cluster Console, window="_console"]. Login with your username and password ({user_name}/{user_password}).
You will be redirected to the Developer perspective of the console. A welcome popup might appear, which you can dismiss for now (click Skip Tour). Also, a popup window might appear with details about the perspective switcher. Feel free to close the popup window (or click Next if you want to know more). Finally, you should be redirected to a view which lists the different OpenShift projects (also known as namespaces) you have access to.

The list of namespaces you have access to will depends on which modules you have deployed.
The Globex web application is deployed in the globex-{user_name} namespace. Click on Topology in the menu on the left and then click on the globex-{user_name} link to open the topology view of the namespace. The Topology view gives you a graphical representation of the different resources deployed in the namespace.

In the Topology View of the Developer Perspective, expect to see something like this (rearrange the topology as you see fit by dragging the circle symbols that represent the various resources. Please avoid creating connections via the arrows just yet):

The Globex web-app deployment consists of:

Service Description

Service	Description
`globex-web`	The web front-end of the Globex web application. Running on Node.js with an Angular UI.
`globex-store-app`	The backend application of the Globex retail app. Written in Quarkus. Provides catalog, inventory, cart and order services.
`globex-db`	The PostgreSQL database used by the globex-store-app application. Stores the catalog, inventory, customer and order information.
`activity-tracking`	This microservice has a REST endpoint for user activity events generated from the UI. These events are produced to a Kafka topic.
`recommendation-engine`	An example of an application which does real-time processing of an event stream. This application uses Kafka Streams, an event-streaming library, to process the stream of events produced by the activity tracking service to build a list of the most popular products on the web site. This list is exposed as a REST endpoint, and called by the front-end to display featured products.

globex-web

The web front-end of the Globex web application. Running on Node.js with an Angular UI.

globex-store-app

The backend application of the Globex retail app. Written in Quarkus. Provides catalog, inventory, cart and order services.

globex-db

The PostgreSQL database used by the globex-store-app application. Stores the catalog, inventory, customer and order information.

activity-tracking

This microservice has a REST endpoint for user activity events generated from the UI. These events are produced to a Kafka topic.

recommendation-engine

An example of an application which does real-time processing of an event stream. This application uses Kafka Streams, an event-streaming library, to process the stream of events produced by the activity tracking service to build a list of the most popular products on the web site. This list is exposed as a REST endpoint, and called by the front-end to display featured products.

To open the Globex web application, click on the symbol next to the globex-web deployment in the topology view.

This opens a new browser tab pointing to the home page of the Globex Web application. Alternatively, open a new browser tab and navigate to {globex_web_url}[{globex_web_url}, window="_globex"].
The featured product list of the Globex web application home page is empty. This is expected as no user activity events have been generated yet.
On the Globex web site, click on the Cool Stuff Store link on the top menu. From here you can browse through the product catalog, open product detail pages and add items to the shopping cart.
To generate user activity events, click on the symbol next to a product. You can repeat this for a couple of products.
Every like action generates a user activity event that is captured by the activity tracking service and sent to a Kafka topic.
The Kafka broker is installed in the globex-mw-{user_name} namespace. In the same namespace, AMQ streams console, a web UI for viewing Kafka topics and browsing consumer groups, is also installed.
Click to navigate to AMQ streams console. This redirects you to the AMQ streams console login page. For the purpose of this workshop, choose Sign in with Anonymous Session to access the console
You will be presented with the Home page of the console. You can see that a kafka broker has already been setup for you.
From the left-hand menu, navigate to Kafka clusters → kafka → Cluster overview. You can view details about the Kafka cluster that has been setup for you including the number of brokers, the topics and also cluster metrics.
Choose the Topics menu on the left-hand side to see the list of topics.
One of those topics is called globex.tracking, which is the topic that contains the user activity events. Click on the topic name to see the details of the topic. If you liked some products on the web site, the topic should contain some messages.
Click on any of the messages listed to see its contents. In this case, the body of each message consists of a JSON structure of a user activity event from the Globex web application.
If you go back to the list of topics in the AMQ streams console (click Topics on left-hand side) , you will notice a number of topics starting with globex.recommendation. Those are the topics created by the recommendation engine application, which calculates a list of the most popular products based on the user activity stream.
The globex.recommendation-product-score-aggregated-changelog topic contains messages containing the list of most popular products, where the latest message has the current list.
In your browser window, go to the tab pointing to the Globex web application. Navigate to the home page. You should see some items in the list of featured products, corresponding to the list of products you liked.
To demonstrate that the list of featured products is calculated in real-time, you can simulate a number of user activities using a simulator deployed next to the Globex web application.
To use the simulator, go the the browser tab pointing to the web console of the OpenShift cluster, navigate to the Topology view of the globex-{user_name} namespace, and click the symbol next to the activity-tracking-simulator deployment (it will most likely be abbreviated as shown in the screenshot, hovering over the name will expand it).
This opens a Swagger UI page showing the REST API of the simulator.
Click on the POST link, and then on the Try it out link on the right.

If you want, you change the number of user activities that will be generated (the default is 100). Click Execute to execute the REST call to the simulator.
In your browser window, navigate to the tab with the AMQ streams console, and notice how messages are produced in the globex.tracking topic. After a couple of seconds you should also see new messages in the globex.recommendation-product-score-aggregated-changelog topic, reflecting the newly calculated list of featured products.
Go the browser tab with the Globex we UI, refresh the home page, and notice how the list of featured products has changed, as it is being continuously recalculated.
This concludes the walkthrough of the Globex web application for now. The application provides more features, which you will discover while going through some of the modules of this workshop.

Please close all but this Workshop Deployer tab to avoid proliferation of tabs which can make working on other modules difficult.

Proceed to the Workshop Deployer to choose your next module.