Real-World Event Sourcing

Modeling Event Flows

What the schema definition languages don’t provide is a way of visualizing and documenting the flow of events and commands through the system. They let you declare the fields and data types on events and commands, but nothing is built into any of these formats for defining flows.

Any event-sourced system of a complexity larger than “hello world” will come with an intrinsic lack of visibility into how events and commands flow through the system. This will be especially true for process managers. While you can look at the code for an individual process manager to see what it does, you’re not going to want to keep refreshing your memory every few months by re-reading the code for dozens of process managers. This also won’t ...