Pleroma/lib/mix/tasks/relay_follow.ex

defmodule Mix.Tasks.RelayFollow do
  use Mix.Task
  require Logger
  alias Pleroma.Web.ActivityPub.Relay

  @shortdoc "Follows a remote relay"
  def run([target]) do
    Mix.Task.run("app.start")

    :ok = Relay.follow(target)

    # put this task to sleep to allow the genserver to push out the messages
    :timer.sleep(500)
  end
end