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

Recovering from errors with supervisors and supervision trees


At the start of the previous section, we explained the let it crash philosophy, and why you should follow it to build reliable, fault-tolerant applications. Having learned about the mechanisms that Elixir provides to detect errors, we will now look at supervisors, which build on top of these mechanisms to provide us a way to recover from errors.

Before diving into supervisors, we want to point out an important aspect regarding error handling in applications that follow the let it crash philosophy. We've been discussing how this approach changes the way you handle errors, and that it provides fault tolerance because you can recover from errors by detecting them and taking some corrective action. However, this approach shouldn't be used with errors that you know beforehand may happen during the normal execution flow of your program, especially if you have a clean way of dealing with them. For instance, a process that's responsible...