task-run-on-remote_clustered-node.ex

defmodule TaskRunnerGenServer do
  use GenServer

  @impl true
  def init(%{remote_node: remote_node} = args) do
   # GenServer.start_link(TaskRunnerGenServer, %{remote_node: "REMOTE_NOTE_AT0M"}, name: TaskRunnerGenServer)
   {:ok, %{ref: nil, node: remote_node}} 
  end
  
  def start_task do
    GenServer.call(__MODULE__, :start_task)
  end

  @impl true
  def handle_call(:start_task, _from, %{ref: ref} = state) when is_reference(ref) do
    {:reply, :ok, state}
  end

  def handle_call(:start_task, _from, %{ref: nil, node: node} = state) do
    # ModuleName.TaskRunner -> Make sure you have a task supervisor running on remote node
    task = Task.Supervisor.async_nolink({ModuleName.TaskRunner, node}, ModuleName.Stats, :module_function, [])
    dbg(task)

    {:reply, :ok, %{state | ref: task.ref}}
  end

  @impl true
  def handle_info({ref, answer}, %{ref: ref} = state) do
    Process.demonitor(ref, [:flush])  # We don't care about the DOWN message now, so let's demonitor and flush it
    IO.inspect(answer)
    {:noreply, %{state | ref: nil}}
  end

  # The task failed
  def handle_info({:DOWN, ref, :process, pid, reason}, %{ref: ref} = state) do
    # Log and possibly restart the task...
    IO.inspect(reason)
    {:noreply, %{state | ref: nil}}
  end
end