Craft GraphQL APIs in Elixir with Absinthe

Event Modeling

Subscriptions push data in response to events or actions within your system, so it isn’t enough to think of subscriptions as a purely API-related concern. A system that can’t model change will have a very hard time communicating about changes to subscribers. Designing our application, we want to arrive at a model that lets us track the life cycle of an order as it is started, completed, and ultimately picked up by the customer. Along the way, each of these changes should be transmitted immediately to employees tasked with making the order, as well as to the hungry customer waiting for their food.

This part of the system is a bit more involved than the menu, so we’re going to take it in pieces. The first piece just focuses ...