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

Working with processes


After seeing the conceptual model of how processes work inside the BEAM, we will now see how we can work with them. Namely, we will cover how to work with processes, how to pass messages between them, and, to showcase how we can use processes to maintain state, we will build a component of our ElixirDrip app, the cache worker.

 

 

 

 

 

 

Creating processes

You create a process by calling the Kernel.spawn/1 function, which receives an anonymous function with no arguments:

iex> self()
#PID<0.85.0>
iex> spawn(fn ->
...>   :timer.sleep(2000)
...>   IO.puts "I'm running in process #{inspect(self())}"
...> end)
#PID<0.91.0>
I'm running in process #PID<0.91.0>

In this example, we're first calling self(), which returns the PID of the current process. In this case, it returned the PID of the shell process. Then, we use the spawn function to create a new process. As previously stated, it receives an anonymous function that will run in the newly created...