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

## Cleaning up the tables
We’re saving the state of each game in the `:game_state` table, but so far, we haven’t removed that state when the game is over. The `:game_state` table continues to grow and use memory unless we delete a game’s key from the `:game_state` table when the supervisor terminates the child process or when the child process times out.

To clean that data up when a game ends normally, we add a call to `:ets.delete/2` in the `GameSupervisor.stop_game/1` function:
```Elixir
def stop_game(name) do
  :ets.delete(:game_state, name)
  Supervisor.terminate_child(__MODULE__, pid_from_name(name))
end
```

# Cleaning up the tables
We’re saving the state of each game in the `:game_state` table, but so far, we haven’t removed that state when the game is over. The `:game_state` table continues to grow and use memory unless we delete a game’s key from the `:game_state` table when the supervisor terminates the child process or when the child process times out.

To clean that data up when a game ends normally, we add a call to `:ets.delete/2` in the `GameSupervisor.stop_game/1` function:
```Elixir
def stop_game(name) do
  :ets.delete(:game_state, name)
  Supervisor.terminate_child(__MODULE__, pid_from_name(name))
end
```

Cleaning Up After a Game

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

Cleaning Up After a Game

Cleaning up the tables