Hi!
I’ve been able to setup child nodes, but I’m trying to get them online. The intention is to make the nodes act as separate computers, such that I can broadcast messages to them via udp.

Code I’ve been using for parent node:

Node.start(:master@localhost, :shortnames)

(When running :longnames, I get a name error when initializing child nodes)

Code for initializing child nodes:

defmodule Child_Nodes do

  def init child_names do
    :os.cmd('epmd -daemon')
    for child_name <- child_names do
      {:ok, node} = start_child child_name
      load_code node
    end
  end

  def project_module_path do
    Path.absname('_build/dev/ebin') |>
    to_charlist()
  end

  def start_child name do
    :slave.start(:localhost, name)
  end

  def load_code node do
    :rpc.block_call(node, :code, :add_paths, [:code.get_path()])
    :rpc.block_call(node, :code, :add_paths, [project_module_path()])
  end
end

This allows me to run my projects code on the child_nodes and access them using Node.ping(). However, each node are going to find eachother over udp using this module, with different ports:

defmodule Broadcasting do

  @broadcast_timeout 1000

  @localhost {10, 0, 0, 68}

  #Node-name format: OrderHandler_<port>@<address>

  def init port do

    {:ok, socket} = :gen_udp.open(port, [active: true, broadcast: true])

    Task.async fn -> broadcast socket, port end

    IO.puts "Node at port #{port} initialized"

    listen socket, port

  end

  def broadcast socket, port do

    :gen_udp.send(socket, {255,255,255,255}, port, to_string(port))

    :timer.sleep(@broadcast_timeout)

    broadcast socket, port

  end

  def listen socket, port do

    local_msg = to_string(port)

    receive do

      {:udp, _socket, _address, port, ^local_msg} ->

        IO.inspect port

        IO.puts "localmsg"

        listen socket, port

      {:udp, _socket, address, remote_port, _msg} ->

        string_address = ip_to_string(address)

        IO.puts "new node added at port: #{port}"

        #"OrderHandler_" <> to_string(remote_port) <> "@" <> string_address |> String.to_atom |> Node.ping

        #localhost-version

        "OrderHandler_" <> to_string(remote_port) <> "@localhost" |> String.to_atom |> Node.ping

      end

  end

  def ip_to_string ip do

    :inet.ntoa(ip) |> to_string()

  end

end

Is it possible to bring all child nodes online?