This repo is Part Four (of eight) of a workshop/activity/tutorial that comprises the "Vac-Seen System". This system is associated with, and specifically created for, the Red Hat OpenShift Sandbox.

At the end of this tutorial you will have an instance of a microservice that is running in an OpenShift cluster. The microservice will generate events into an Apache Kafka topic.

If you need help or get stuck, email devsandbox@redhat.com. If you find a defect, create an Issue in this repository.

The following three prerequisites are necessary:

1. An account in OpenShift Sandbox (No problem; it's free). This is not actually necessary, since you can use this tutorial with any OpenShift cluster.
2. The oc command-line tool for OpenShift. There are instructions later in this article for the installation of oc.
3. Your machine will need access to a command line; Bash or PowerShell, either is fine.

You can use this activity regardless of whether your PC runs Windows, Linux, or macOS.

This tutorial is structured so that a .NET developer can perform this workshop using free resources: the aformentioned Kafka cluster and Openshift sandbox. In addition, a few open source prerequesites are required.

The scenario is this: Field personnel report the administration of COVID-19 vaccinations. These vaccination events are sent to a Kafka cluster.

This particular repo references a microservice called "vac-seen-generator". It creates simulated vaccination events, which contain the following data:

• RecipientID — string that identifies who got the shot. It's a GUID.
• EventTimestamp — date and time
• CountryCode — the hard-coded, two-character ISO code for the country. Currently "us".
• VaccinationType — string that denotes which vaccination, for example, Pfizer or Moderna.
• ShotNumber — an integer indicating which shot this is for this recipient, i.e. first, second, third, etc. this repository.

This microservice has an API endpoint to which you can post a date. For that date, a random number of random events (from 1 to 40) are added to the Kafka event stream. This API can be called multiple times; it uses the current date and time as the EventTimestamp property. Calling it over and over simply adds more events to the Kafka event stream.

This microservices depends on a Kafka instance and OpenShift Service Binding. Without those two dependencies, this program will do nothing.

The user:

1. Creates this vac-seen-generator app in their cluster using the "from Git" option.
2. Makes available a managed Kafka instance.
3. Binds their managed Kafka cluster to the app using Service Binding.
4. Can now use this program.

Run this command get pull the image from the image registry and create the OpenShift application:

oc new-app --name=vac-seen-generator --image=quay.io/donschenck/vac-seen-generator:latest

The microservice is now up and running.

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