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

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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

We start and stop game processes all the time.

All these conditions have an impact on which strategy we choose. Let’s take a closer look at the strategies next.

## One-for-one
With the **one-for-one strategy**, if a single process terminates, the supervisor will restart just that one process. This is best if the group of supervised processes can work independently of one another. In other words, if restarting the process will not upset the functioning of the whole group of processes, we use the one-for-one strategy.

We start and stop game processes all the time.

All these conditions have an impact on which strategy we choose. Let’s take a closer look at the strategies next.

# One-for-one
With the **one-for-one strategy**, if a single process terminates, the supervisor will restart just that one process. This is best if the group of supervised processes can work independently of one another. In other words, if restarting the process will not upset the functioning of the whole group of processes, we use the one-for-one strategy.

Understand the details of child process in supervision strategies.

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

Conditions of Child Processes in Supervision

One-for-one