instructions.md

Write a simple server that sends a notification about every 2 seconds. To receive the notification, a client has to register with the server.

ticker.ex

defmodule Ticker do
  @interval 2000
  @name :ticker
  
  def run do
    pid = spawn(__MODULE__, :generator, [[]])
    :global.register_name(@name, pid)
  end
  
  def register(client_pid) do
    send :global.whereis_name(@name), {:register, client_pid}
  end
  
  def generator(clients) do
    receive do
      {:register, pid} ->
        IO.puts "registering #{inspect pid}"
        generator([pid|clients])
    after @interval
      IO.puts "tick"
      Enum.each clients, &(send &1, {:tick})
      generator(clients)
    end
  end
end

defmodule Client do
  def run do
    pid = spawn(__MODULE__, :receiver, [])
    Ticker.register(pid)
  end
  
  def receiver do
    receive do
      {:tick} ->
        IO.puts "tock in client"
        receiver()
    end
  end
end