Practical Event Sourcing with Scala
Practical Event Sourcing with Scala
A comprehensive example based on Scala, Play and Akka Streams
About the Book
This book takes a very practical and rather unusual approach towards the event sourcing architecture. Instead of diving into the DDD terminology, which is usually popular in the Enterprise, we will use this pattern to implement a typical Web application.
Instead of C# or Java, we will be using Scala as the backend language and JavaScript (ES6) as the frontend one. Along the way, we will also make use of some other supporting technologies such as Play, Akka Streams, Kafka, React (with Redux), Websockets and even Neo4J.
You don't need to be a Scala guru to understand code samples, but some familiarity with the syntax is required. If you're completely new to Scala, I highly recommend you go through the free sample of my other book - Modern Web Development with Scala. The PDF sample could be read in an hour, but it covers most widely used syntax constructs.
Which versions are used
The main examples use Scala 2.13 and Play 2.8. When additional libraries are needed, their latest versions are used.
Acknowledgements
My special thanks go to Tim Ruhland for his enormous help in eliminating typos and errors. The cover illustration was designed by Freepik
About the Author
Bundles that include this book
Table of Contents
- Preface
-
Chapter 1. The initial project
- Preparing the environment
- Initializing the project
- The backend part
- The frontend part
-
Chapter 2. Handling simple events
- Event sourcing basics
- Preparing the event store
- Working with log records
- The read service
- Akka Streams in 5 minutes
- Updating the state with Akka Streams
- Producing events
- Implementing the controller
- Learning React in 5 minutes
- Managing tags with React
-
Chapter 3. Data processing pipeline
- Introducing Kafka
- Using Kafka from Scala
- Server-sent events
- Managing state with Redux
- Implementing Kafka consumers
-
Chapter 4. Validating and querying data
- Dealing with questions
- Linking questions to users
- Implementing server-side validation
- Introducing Neo4J
- The Cypher query language
- Executing Neo4J statements
- Rewriting the read service
- Integrating user-related events
- Initializing the state
-
Chapter 5. Frontend routing
- Adding the question controller
- Designing the views
- Nested views
- The Ask question view
- Showing validation errors
- The question list view
- Confirmation service
- Dealing with question threads
- The question details view
- Routing it all together
-
Chapter 6. Answers and upvotes
- Answers and upvotes
- Validating new event types
- Adjusting the read state
- Answers on the frontend
-
Chapter 7. Time travelling
- Rewinding in chunks
- Time travel dashboard
- Using Websockets
- Closing remarks
- Appendix A. Source code
The Leanpub 60-day 100% Happiness Guarantee
Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
Do Well. Do Good.
Authors have earned$12,130,341writing, publishing and selling on Leanpub, earning 80% royalties while saving up to 25 million pounds of CO2 and up to 46,000 trees.
Learn more about writing on Leanpub
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
Top Books
- #1
Ansible for DevOps
Jeff GeerlingAnsible is a simple, but powerful, server and configuration management tool. Learn to use Ansible effectively, whether you manage one server—or thousands.
- #2
Jetpack Compose internals
Jorge CastilloJetpack Compose is the future of Android UI. Master how it works internally and become a more efficient developer with it. You'll also find it valuable if you are not an Android dev. This book provides all the details to understand how the Compose compiler & runtime work, and how to create a client library using them.
- #3
Functional Programming Made Easier
Charles ScalfaniA Functional Programming book from beginner to advanced without skipping a single step along the way.
In my 40 years of programming, I've felt that programming books always let me down, especially Functional Programming books. So, I wrote the book I wish I had 5 years ago.
Functional Programming will never be easy, but it can be easier.
- #4
Windows 11 Field Guide
Rafael Rivera and Paul ThurrottThe Windows 11 Field Guide is a full-length e-book about the latest version of Microsoft Windows, aimed at those users who will upgrade from Windows 10 or acquire Windows 11 with a new PC.
- #5
Mastering STM32 - Second Edition
Carmine NovielloWith more than 1200 microcontrollers, STM32 is probably the most complete ARM Cortex-M platform on the market. This book aims to be the most complete guide around introducing the reader to this exciting MCU portfolio from ST Microelectronics and its official CubeHAL and STM32CubeIDE development environment.
- #6
Getting to Know IntelliJ IDEA
Trisha Gee and Helen ScottIf we treat our IDE as a text editor, we are doing ourselves a disservice. Using a combination of tutorials and a questions-and-answers approach, Getting to Know IntelliJ IDEA will help you find ways to use IntelliJ IDEA that enable you to work comfortably and productively as a professional developer.
- #7
node-opcua by example
Etienne RossignonGet the best out of node-opcua through a set of documented examples by the author himself that will allow you to create stunning OPCUA Servers or Clients.
- #8
R Programming for Data Science
Roger D. PengThis book brings the fundamentals of R programming to you, using the same material developed as part of the industry-leading Johns Hopkins Data Science Specialization. The skills taught in this book will lay the foundation for you to begin your journey learning data science. Printed copies of this book are available through Lulu.
- #9
C# for Babies
Maarten Balliauw, Khalid Abuhakmeh, and Arina KovrizhkinaAn illustrated book perfect for teaching your little ones the basics of the C# programming language!
- #10
Introducing EventStorming
Alberto BrandoliniThe deepest tutorial and explanation about EventStorming, straight from the inventor.
Top Bundles
- #1
CCIE Service Provider Ultimate Study Bundle
2 Books
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification... - #3
Pattern-Oriented Memory Forensics and Malware Detection
2 Books
This training bundle for security engineers and researchers, malware and memory forensics analysts includes two accelerated training courses for Windows memory dump analysis using WinDbg. It is also useful for technical support and escalation engineers who analyze memory dumps from complex software environments and need to check for possible... - #4
Software Architecture
2 Books
"Software Architecture for Developers" is a practical and pragmatic guide to modern, lightweight software architecture, specifically aimed at developers. You'll learn:The essence of software architecture.Why the software architecture role should include coding, coaching and collaboration.The things that you really need to think about before... - #5
The Python Craftsman
3 Books
The Python Craftsman series comprises The Python Apprentice, The Python Journeyman, and The Python Master. The first book is primarily suitable for programmers with some experience of programming in another language. If you don't have any experience with programming this book may be a bit daunting. You'll be learning not just a programming... - #6
1500 QUIZ COMMENTATI (3 libri)
3 Books
Tre libri dei QUIZ MMG Commentati al prezzo di DUE! I QUIZ dei concorsi ufficiali di Medicina Generale relativi agli anni: 2000-2001-2003-2012-2013-2014-2015-2016-2017-2018-2019-2020-2021 +100 inediti Raccolti in unico bundle per aiutarvi nello studio e nella preparazione al concorso. All'interno di ogni libro i quiz sono stati suddivisi per... - #7
Growing Agile: The Complete Coach's Guide
7 Books
Growing Agile: Coach's Guide Series This bundle provides a collection of training and workshop plans for a variety of agile topics. The series is aimed at agile coaches, trainers and ScrumMasters who often find themselves needing to help teams understand agile concepts. Each book in the series provides the plans, slides, handouts and activity...
