Gain insights into building scalable backend applications with Elixir, OTP, and Phoenix. Learn about persistent connections via Phoenix Channels, and explore distinct, decoupled application layers.

Functional Web Development with  Elixir, OTP and Phoenix by The Pragmatic Programmer_ .png

elixir_islands_test.tar.gz

elixir-app

pheonix-app

elixir-app-guesses

island-interface

phoenix-app-compiled

phoenix-app-iex

phoenix-app-form

phoenix-app-new-module

client-connection

presence

phoenix-app-final

without-presence

Elixir and OTP provide exceptional tools to build rock-solid backend applications that scale. In this course, you’ll build a web application in a radically different way, with a backend that holds application state. You’ll use persistent Phoenix Channel connections instead of HTTP’s request-response, and create the full application in distinct, decoupled layers.

In Part 1, you’ll start by building the business logic as a separate application, without Phoenix. You’ll model the application domain with Elixir functions and simple data structures.

In Part 2, you’ll add in the GenServer Behaviour to make managing in-memory state a breeze. 

In Part 3, you’ll build a web interface with Phoenix where you’ll use Phoenix Channels to establish persistent connections between the stateful server and a stateful front-end client.

Needless to say, you’re going to love this way of building web apps!

Functional Web Development with Elixir, OTP and Phoenix

Exception handling is the preferred way to implement fault-tolerance in Elixir systems?

Exception handling is the preferred way to implement fault-tolerance in Elixir systems?

It can’t send a signal, because it crashed

When a process in a group of linked processes crashes, it sends an exit signal to which of the following?

When a process in a group of linked processes crashes, it sends an exit signal to which of the following?

Note down that another process crashed, and continue running

Ignore the signal, unless a callback is implemented

Try to determine the cause of the exit signal

A process in a group of linked processes receives an exit signal. What would it do?

A process in a group of linked processes receives an exit signal. What would it do?

When creating a supervisor process, which of the following best describes what we can specify?

When creating a supervisor process, which of the following best describes what we can specify?

A supervisor itself may crash, restart and fail again, repeatedly. There’s no way to fix this.

A supervisor itself may crash, restart and fail again, repeatedly. There’s no way to fix this.

Only those processes that started after the crashed process

The crashed process as well as those that started after it

In the _rest-for-one_ strategy, when a process crashes, which of the following are restarted by the supervisor?

In the rest-for-one strategy, when a process crashes, which of the following are restarted by the supervisor?

A module has the statement `use GenServer, start: {__MODULE__, :start_link, []}, restart: :transient`. When would the supervisor restart its child processes?

A module has the statement <code>use GenServer, start: {__MODULE__, :start_link, []}, restart: :transient</code>. When would the supervisor restart its child processes?

Which supervisor strategy is suitable for processes that will come and go as the application runs?

Which supervisor strategy is suitable for processes that will come and go as the application runs?

The `start/2` function creates a Supervisor process

A "top-level supervisor" process is created by `start/2` function

When you create a new application with the `mix new` command with the `–sup` argument, what is true about the module that is auto-generated for you?

When you create a new application with the <code>mix new</code> command with the <code>–sup</code> argument, what is true about the module that is auto-generated for you?

Restarting a failed process helps the program keep running as if nothing happened?


Restarting a failed process helps the program keep running as if nothing happened?

We want to store a set of values against a given key in an ETS table. What type should we use?

We want to store a set of values against a given key in an ETS table. What type should we use?

`:ets.new(:state, [:public, :named_table])`

`:ets.new(:state, [:private, :named_table])`

`:ets.new(:state, [:protected, :named_table])`

We want to create an ETS table named `state` in our application such that all processes can read and write to it. Which of the following is the right way to create it?

We want to create an ETS table named <code>state</code> in our application such that all processes can read and write to it. Which of the following is the right way to create it?

Let's test our understanding of the concepts covered so far.

Introduction

Mapping Our Route

Model Data and Behavior

Working of State Machines

Add OTP for Concurrency and Fault Tolerance

Process Supervision for Recovery

Generate a New Web Interface with Phoenix

Create Persistent Connections with Phoenix Channels

Appendix

Quiz