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

Flow


Since the early days, Elixir has allowed us to easily process collections using the Enum and Stream modules. In the first case, the collection is traversed as soon as it reaches an Enum call, if we use the respective Stream function instead, we can delay the actual enumeration of the collection until the very last moment. This is why we say Stream functions are lazy and Enum functions are eager.

As a result, if we transform a collection by chaining Enum.map/2 calls, an intermediate collection will be created for each call to an Enum function. This behavior contrasts with the behavior we would get if we chained a bunch of Stream.map/2 calls. In the latter case, the entire collection would be traversed at most once, and only when the resulting stream reaches an Enum function (such as Enum.to_list/1), forcing each element of the stream to be evaluated.

The Enum and Stream modules provide an invaluable set of tools to work with collections, but do not leverage the Elixir capability to run...