灵丹妙药simple_one_for_one主管的start_child以未定义的handle_call/3终止

Question

我正在尝试创建一个使用gproc作为进程注册表的监控器。以下代码定义了监控器：

defmodule QueueSupervisor do
    use Supervisor

    def start_link do
        GenServer.start_link(__MODULE__, [], name: :model_queue)
    end

    def create_queue(name) do
        Supervisor.start_child(:model_queue, [name])
    end

    def init([]) do
        children = [
            worker(ModelQueueWriter, [])
        ]

        supervise(children, strategy: :simple_one_for_one)
    end

    def terminate(reason,_state) do
        Logger.info "terminating: #{inspect self}: #{inspect reason}"
        :ok
    end
end

主管一开始就很有魅力。但是，在调用create_queue(:some_name)时，我会得到一个未定义的函数错误：

function QueueSupervisor.handle_call({:start_child, [:some_name]}, {#PID<0.2278.0>, #Reference<0.0.3.3361>}, {{:simple_one_for_one, 3, 5}, [{ModelQueueWriter, {ModelQueueWriter, :start_link, []}, :permanent, 5000, :worker, [ModelQueueWriter]}]}

ModelQueueWriter是一个简单的genserver，使用gproc命名：

defmodule ModelQueueWriter do
    use GenServer

    def start_link(queue_name) do
        GenServer.start_link(__MODULE__, [], name: via_tuple(queue_name))
    end

    defp via_tuple(queue_name) do
        {:via, :gproc, {:n, :l, {:model_queue, queue_name}}}
    end

    def init(_), do: %{:ok, []}
end

我正在使用灵丹妙药1.4，并遵循doc，加上这个示例。

我遗漏了什么？

应请求提供完整的错误消息：

** (exit) exited in: GenServer.call(:model_queue, {:start_child, [:some_name]}, :infinity)
    ** (EXIT) an exception was raised:
        ** (UndefinedFunctionError) function QueueSupervisor.handle_call/3 is undefined or private
        (ecohesion_web) QueueSupervisor.handle_call({:start_child, [:model_queue]}, {#PID<0.2278.0>, #Reference<0.0.1.8826>}, {{:simple_one_for_one, 3, 5}, [{ModelQueueWriter, {ModelQueueWriter, :start_link, []}, :permanent, 5000, :worker, [ModelQueueWriter]}]})
        (stdlib) gen_server.erl:629: :gen_server.try_handle_call/4
        (stdlib) gen_server.erl:661: :gen_server.handle_msg/5
        (stdlib) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
11:01:17.094 [error] GenServer :model_queue terminating
** (UndefinedFunctionError) function QueueSupervisor.handle_call/3 is undefined or private
(ecohesion_web) QueueSupervisor.handle_call({:start_child, [:model_queue]}, {#PID<0.2278.0>, #Reference<0.0.1.8826>}, {{:simple_one_for_one, 3, 5}, [{ModelQueueWriter, {ModelQueueWriter, :start_link, []}, :permanent, 5000, :worker, [ModelQueueWriter]}]})
(stdlib) gen_server.erl:629: :gen_server.try_handle_call/4
(stdlib) gen_server.erl:661: :gen_server.handle_msg/5
(stdlib) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
Last message: {:start_child, [mode_queue]}
State: {{:simple_one_for_one, 3, 5}, [{ModelQueueWriter, {ModelQueueWriter, :start_link, []}, :permanent, 5000, :worker, [ModelQueueWriter]}]}
       (elixir) lib/gen_server.ex:737: GenServer.call/3
(ecohesion_web) lib/ecohesion_web/archive_writer/queue_supervisor.ex:28: QueueSupervisor.create_queue/1

Answer 1

您正在启动一个GenServer，而不是QueueSupervisor.start_link/0中的Supervisor。这应该是可行的：

defmodule QueueSupervisor do
  def start_link do
    Supervisor.start_link(__MODULE__, [], name: :model_queue)
  end
end

为什么这会让主管开始正常工作呢？

它启动一个GenServer；只是您使用的参数与Supervisor.start_link/3和GenServer.start_link/3兼容。