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

Using (D)ETS


In the previous section, we implemented the ElixirDrip text search functionality by using Task.async_stream/5 to search several text files at the same time. The text search function lived on the ElixirDrip.Storage.Search module and its last iteration could be used like this:

iex> alias ElixirDrip.Storage.Search

iex> media_ids = ["25", "8", "6", "7"]

iex> search_expression = "media"

iex> Search.safe_task_stream_search_for(media_ids, 
search_expression)

%{
  "6" => [{1, "Content of media 6."}],
  "7" => [{1, "Content of media 7."}],
  "8" => [{1, "Content of media 8."}]
}

It returned a map with entries for every searched file whose search ended on the allotted time. For each media id, it yields a list of two-element tuples, where the first tuple element corresponds to the line where the expression was found and the second element contains the actual line's contents.

Remember that ElixirDrip spawns a CacheWorker to keep files in memory for a while to speed...