supervision_tree_viz.ex

defmodule SupervisionTreeViz do
  def to_dot(supervisor) do
    edges = build_edges(supervisor, [])
    
    """
    digraph supervision_tree {
      node [shape=box, style=rounded];
      #{Enum.join(edges, "\n  ")}
    }
    """
  end

  defp build_edges(supervisor, acc) do
    children = Supervisor.which_children(supervisor)
    
    Enum.reduce(children, acc, fn {id, pid, type, _modules}, edges ->
      parent_name = inspect(supervisor)
      child_name = "#{id}_#{inspect(pid)}"
      edge = ~s("#{parent_name}" -> "#{child_name}";)
      
      case type do
        :supervisor when is_pid(pid) ->
          build_edges(pid, [edge | edges])
        _ ->
          [edge | edges]
      end
    end)
  end
end

# Usage in IEx:
File.write!("sup_tree.dot", SupervisionTreeViz.to_dot(YourApp.Supervisor))