Question

我一直在学习Elixir，并尝试构建类似于Mars Rover Kata的应用程序

我正在使用GenServer维护单个流动站的状态，并在注册表的帮助下尝试生成一个密钥，即流动站名称

Rover.ex代码

  defstruct [:x, :y, :direction, :name]

  def start_link({x, y, d, name}) do
    GenServer.start_link(__MODULE__, {x, y, d, name}, name: RegistryHelper.create_key(name))
  end

  def init({x, y, d, name}) do
    {:ok, %Rover{x: x, y: y, direction: d, name: name}}
    # {:ok, %{}}
  end

  def get_state(name) do
    GenServer.call(RegistryHelper.create_key(name), :get_state)
  end

  def handle_call(:get_state, _from, state) do
    {:reply, {:ok, {state.x, state.y, state.direction}}, state}
  end

Registry_helper.ex

defmodule RegistryHelper do

    @spec create_key(String.t) :: {:via, atom, {atom, String.t}}
    def create_key(name), do: {:via, Registry, {Rover.Registry, name}}

    @spec register(String.t) :: {:ok, pid} | {:error, {:already_registered, pid}}
    def register(name), do: Registry.register(Rover.Registry, create_key(name), [])

    @spec get_pid(String.t) :: pid
    def get_pid(name) do
      [{pid, _}] = Registry.lookup(Rover.Registry, name)
      pid
    end
  end

 ** (ArgumentError) unknown registry: Rover.Registry
 code: {:ok, _} = Rover.start_link({9, 9, :N, "rover0"})
 stacktrace:
   (elixir) lib/registry.ex:1154: Registry.key_info!/1
   (elixir) lib/registry.ex:213: Registry.whereis_name/2
   (stdlib) gen.erl:76: :gen.start/6
   test/rover_test.exs:5: (test)

注册表模块是否有问题，或者我将参数传递给start_link的方式？

Answer 1

您永远不会启动Registry。除非您有更好的注册位置（例如Application.start/2中的某个位置），否则最简单的解决方法是从Rover.start_link/1开始注册：

def start_link({x, y, d, name}) do
  # Better start it supervised!
  Registry.start_link(keys: :unique, name: Rover.Registry)

  GenServer.start_link(
    __MODULE__, {x, y, d, name},
    name: RegistryHelper.create_key(name))
end

如何在Elxir中修复'**（ArgumentError）未知注册表：Rover.Registry'

1 个答案: