Real-World Event Sourcing

Building a Flight Tracker with Injection and Notification

One of the best aspects of event sourcing is that it’s fun. As you’ve discovered already, the code to write notifiers and injectors is trivial—they’re simply event handlers and event emitters. The trick with event sourcing I/O is, as with so many problems, proper modeling. To start modeling injection and notification, and hopefully have a lot of fun with a sample application, let’s build a flight tracker.

This flight tracker will capture incoming events from a real-time flight data source and inject them into the internal event stream. You’ll set up a notifier to send notifications to a user when changes happen to a flight they’re interested in and a projector that will store the most ...