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

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presence

phoenix-app-final

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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

The way to get processes to know when other processes crash is to link them. That’s what we explore next.

## New IEx session



First, let's alias the `DemoProc` module:
```IEx
alias IslandsEngine.DemoProc 
linked = spawn(DemoProc, :loop, [])
Process.link(linked) 
Process.alive?(linked) 
send(linked, "Hello Process!") 
```

>**Use `spawn_link` to avoid race conditions**
>
>When we spawn a process first, then link to it, there’s a small window of time where either process might terminate before the link is complete. `Kernel.spawn_link/3` eliminates this race condition. It's like spawning a process and then linking, except that it’s an atomic action. There’s no time separation between spawning and linking.

The way to get processes to know when other processes crash is to link them. That’s what we explore next.

# New IEx session



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

Visualizing Live Streaming Data with Elixir, Kafka, and Chart.js

Appendix

Link Processes

New IEx session