These exercises are designed to follow along with the course modules to provide hands-on practical experience.
The first two exercises are pure event modeling, and can be completed using nothing more than some sticky notes and a pencil, or your favorite drawing/diagramming application. They will include links to images of how the event model should appear as it evolves.
Each step will include a link to a JSON export of the event model that can be used in the third-party event modeling tool, Evident Design.
Exercise 3 involves actually implementing in code the system design that we captured in the event model. The codebase is written in Kotlin for two reasons:
- To make use of to the excellent Kafka Java Client and Kafka Streams Library via Kotlin's easy Java interop
- To illustrate some of the functional domain modeling techniques for implementing the event model as described in the course
Each exercise is a named branch that links to a detailed README containing instructions, event model images/exports, and codebases at various stages of completion.
The exercises as outlined below are built around the example system described throughout the course:
- an autonomous vehicle ride reservation system.
Rather than leaving their vehicles sitting idle for hours, for example while at work, vehicle owners can make their autonomous vehicles available to pick up and drop off riders like a traditional ride-sharing service.
First, owners must register their vehicles with our service using the vehicle's VIN number.
Next, owners make vehicles available to our service for a specific period.
Then, riders can schedule and pay for rides, and can either cancel prior to pickup, or else confirm pickup and drop-off.
When the owner needs their vehicle, they request its return to take it out of circulation.
Finally, if they no longer want an account, owners can unregister their vehicles from our service.
Exercise 1: Build the Storyboard
This begins the module ending at "The event modeling Workshop: Step 2, Envisioning the User Experience".
In this exercise, we'll build our event model up to the point of functioning like a storyboard for a film.
Exercise 2: Completing the event model
This begins the module ending at "The event modeling Workshop: Step 4, Identifying and Integrating event Streams".
In this exercise, we'll complete our event model by identifying our Command and Read model API, connecting the model components together with data flow arrows, and identifying and integrating our event Streams.
Exercise 3: Implementing an event model on the Streaming Data Platform
This begins the module ending at "Implementing event modelled Systems on the Streaming Data Platform", and just before the conclusion module for the course.
In this exercise, we'll turn our model into code to run our system on the Streaming Data Platform. The event model will guide our creation of domain Transfer Objects, domain Types, and our Decide and Evolve functions. Finally, we'll wire these code components into the Kafka Producer and Streams APIs.
Each step has its own directory containing a README with instructions, and with tests that initially fail.