March 2025
Intermediate to advanced
202 pages
4h 45m
English
Content preview from Real-World Event SourcingBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Work Is a Side Effect
A frequently asked question in new event sourcing projects is “where does the work happen?” Aggregates aren’t allowed to perform side effects or read from external data. Process managers aren’t allowed to perform side effects or read from external data. Projectors can create external data, but they can’t perform “work” either. If you follow the rule that work is a side effect, things may be easier to understand. If work is a mutation of the world outside the event-sourced system, then work is a side effect, and side effects are only allowed through gateways. The core primitives of aggregates, projectors, and process managers must never do work.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.