Lesson 03.3
Transactional outbox
The transactional outbox saves an outgoing event in the same database transaction as the data it describes, and a separate relay publishes it, so the two can never disagree.
Saved, but never told
When a cookie order comes in, Ava does two things: she saves the order on the computer, then she sends a message to the kitchen so they start baking.
Two separate steps. What if something goes wrong in between?
In this lesson you'll
- 1Watch a normal order.
- 2Guess what happens when Ava's tablet dies between the two steps.
- 3Find a rule so the kitchen always hears.