dominoes.livemd

Dominoes

Mix.install([
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"},
  {:tested_cell, github: "brooklinjazz/tested_cell"},
  {:utils, path: "#{__DIR__}/../utils"}
])

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Dominoes

Dominoes are square tiles often placed near each other to make satisfying effects when it falls and knocks each other over.

You're going to make three Domino processes under a Supervisor (Domino1, Domino2, and Domino3), then have them terminate and restart sequentially.

flowchart
S[Supervisor]
S --> Domino1
S --> Domino2
S --> Domino3

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You should be able to cause each Domino process to crash by sending it a :fall message.

We've created the Domino1 server for sake of example.

defmodule Domino1 do
  use GenServer

  def start_link(state) do
    GenServer.start_link(__MODULE__, state, name: __MODULE__)
  end

  def init(state) do
    {:ok, state}
  end

  def handle_info(:fall, _state) do
    raise "Domino1 falls"
  end
end

Create the Domino2 and Domino3 modules. Then configure them with a supervisor such that each Domino process terminates (and restarts) one after the other.

For example:

• Domino1 receives the :fall message. Domino1 crashes. Domino2 then Domino3 are terminated by the supervisor.
• Domino2 receives the :fall message. Domino2 crashes. Domino3 is terminated by the supervisor.

Hint

Use the :rest_for_one strategy for your supervisor.

Commit Your Progress

Run the following in your command line from the beta_curriculum folder to track and save your progress in a Git commit.

$ git add .
$ git commit -m "finish dominoes exercise"

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