Using Ecto & Phoenix init/2 Callbacks

endpoint.ex

defmodule MyApp.Endpoint do
  use Phoenix.Endpoint, otp_app: :my_app
  
  # ... a bunch of plugs
  
  def init(_, config) do
    port = System.get_env("PORT")
    
    http_config =
      config
      |> Keyword.get(:http, [])
      |> Keyword.put_new(:port, port)
    
    config = Keyword.put(:http, http_config)
    
    {:ok, config}
  end
end

repo.ex

defmodule MyApp.Repo do
  use Ecto.Repo, opt_app: :my_app
  
  # ... possibly other functionality
  
  def init(_, config) do
    url = System.get_env("DATABASE_URL")
    
    config = Keyword.put_new(:url, url)
    
    {:ok, config}
  end
end