Book Image

Scala Reactive Programming

By : Rambabu Posa
Book Image

Scala Reactive Programming

By: Rambabu Posa

Overview of this book

Reactive programming is a scalable, fast way to build applications, and one that helps us write code that is concise, clear, and readable. It can be used for many purposes such as GUIs, robotics, music, and others, and is central to many concurrent systems. This book will be your guide to getting started with Reactive programming in Scala. You will begin with the fundamental concepts of Reactive programming and gradually move on to working with asynchronous data streams. You will then start building an application using Akka Actors and extend it using the Play framework. You will also learn about reactive stream specifications, event sourcing techniques, and different methods to integrate Akka Streams into the Play Framework. This book will also take you one step forward by showing you the advantages of the Lagom framework while working with reactive microservices. You will also learn to scale applications using multi-node clusters and test, secure, and deploy your microservices to the cloud. By the end of the book, you will have gained the knowledge to build robust and distributed systems with Scala and Akka.
Table of Contents (16 chapters)

Akka Persistence Query

In this section, we will develop a WF (Weather Forecasting) Reactive system using the following technology stack:

  • Akka Persistence API
  • Akka Persistence Query API
  • Scala
  • Apache Cassandra

As we discussed in Chapter 7, Working with Reactive Streams, Akka Persistence supports the CQRS/ES (Command and Query Responsibility Segregation with Event Sourcing) Design pattern.

CQRS/ES is a Reactive Statement Management and Persistence pattern.

The Akka Persistence API is used to write data into a data store, whereas the Akka Persistence Query API is used to read data from a data store. Here we can use any RDBMS or No SQL database as a data store. We will use Apache Cassandra as our WF Reactive System data store for both the WRITE and READ sides.

Building blocks of Akka...