Book Image

Mastering Elixir

By : André Albuquerque, Daniel Caixinha
Book Image

Mastering Elixir

By: André Albuquerque, Daniel Caixinha

Overview of this book

Running concurrent, fault-tolerant applications that scale is a very demanding responsibility. After learning the abstractions that Elixir gives us, developers are able to build such applications with inconceivable low effort. There is a big gap between playing around with Elixir and running it in production, serving live requests. This book will help you fll this gap by going into detail on several aspects of how Elixir works and showing concrete examples of how to apply the concepts learned to a fully ?edged application. In this book, you will learn how to build a rock-solid application, beginning by using Mix to create a new project. Then you will learn how the use of Erlang's OTP, along with the Elixir abstractions that run on top of it (such as GenServer and GenStage), that allow you to build applications that are easy to parallelize and distribute. You will also master supervisors (and supervision trees), and comprehend how they are the basis for building fault-tolerant applications. Then you will use Phoenix to create a web interface for your application. Upon fnishing implementation, you will learn how to take your application to the cloud, using Kubernetes to automatically deploy, scale, and manage it. Last, but not least, you will keep your peace of mind by learning how to thoroughly test and then monitor your application.
Table of Contents (18 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
5
Demand-Driven Processing
Index

Elixir applications


Elixir inherits a lot of concepts from Erlang/OTP, and the application's behaviour is one of those concepts. For the Erlang VM, an application is a component that can be started and stopped as a single unit, and is described by an .app file (for example, hello_world.app) that defines, among other things, the Application Module Callback. This is a module that needs to implement a  start/2 function that's responsible for kickstarting the application, usually by spawning its top-level supervisor (in the next chapter, you'll learn all about supervisors). In a way, you can think about the start/2 function as the common main entry point on applications developed with other programming languages.

Because we're using Elixir, we don't need to explicitly specify the .app file. The Elixir compiler will find the correct application module callback by looking for a module using the Application behaviour and will then generate the .app file for us.

Let's use mix to generate a sample...