Erlang supervisor / gen_server例外退出:noproc

时间:2015-08-12 15:51:16

标签: emacs erlang behavior supervisor gen-server

我现在正疯狂地试图找出问题所在。

基本上我只想设置一个简单的Supervisor,其中包含1个服务器和1个gen_event-behavior模块。

现在的问题是,我不能再让它成为主管了。

无论我做什么,我都会收到此错误: **例外退出:noproc

当使用text-tracer时,它显示它发生在sRPG_supervisor:init / 1中。有了这个,你认为代码有问题,但是当我运行其他人的例子时,我得到完全相同的东西(我已经下载了Joe Armstrongs的例子并测试了sellaprime_supervisor,结果相同)。

当我在虚拟Ubuntu安装中运行它时,它常常很好用。然后我进行了设置,以便我可以在Windows中进行编码,但我从未测试过这种最简单的形式,显然它不是出于某种原因。

因此,如果有人遇到类似的问题,那么找到解决方案会很棒! 我使用erl6.3作为带有OTP 17的Erlang版本。

这是我正在使用的代码,只是来自Emacs生成的骨架的构建: sRPG_supervisor.erl

-module(sRPG_supervisor).

-behaviour(supervisor).

%% API
-export([start_link/0, start_link/1, start/0, start_in_shell_for_testing/0]).

%% Supervisor callbacks
-export([init/1]).

-define(SERVER, ?MODULE).

%%%===================================================================
%%% API functions
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Starts the supervisor
%%
%% @spec start_link() -> {ok, Pid} | ignore | {error, Error}
%% @end
%%--------------------------------------------------------------------
start_link() ->
    supervisor:start_link({local, ?SERVER}, ?MODULE, []).

start() ->
    spawn(fun() ->
          supervisor:start_link({local, ?SERVER}, ?MODULE, _Arg = [])
      end).

start_in_shell_for_testing() ->
    {ok, Pid} = supervisor:start_link({local, ?SERVER}, ?MODULE, _Arg = []),
    unlink(Pid).

start_link(Args) ->
    supervisor:start_link({local, ?SERVER}, ?MODULE, Args).


%%%===================================================================
%%% Supervisor callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever a supervisor is started using supervisor:start_link/[2,3],
%% this function is called by the new process to find out about
%% restart strategy, maximum restart frequency and child
%% specifications.
%%
%% @spec init(Args) -> {ok, {SupFlags, [ChildSpec]}} |
%%                     ignore |
%%                     {error, Reason}
%% @end
%%--------------------------------------------------------------------
init([]) ->
    %% Install sRPG event/error handler
    gen_event:swap_handler(alarm_handler, {alarm_handler, swap}, {sRPG_event_handler, xyz}),



    RestartStrategy = one_for_one,
    MaxRestarts = 1000,
    MaxSecondsBetweenRestarts = 3600,

    SupFlags = {RestartStrategy, MaxRestarts, MaxSecondsBetweenRestarts},

    Restart = permanent,
    Shutdown = 2000,
    Type = worker,

    AChild = {sRPG_server, {sRPG_server, start_link, []},
          Restart, Shutdown, Type, [sRPG_server]},

    {ok, {SupFlags, [AChild]}}.

sRPG_server.erl

-module(sRPG_server).

-behaviour(gen_server).

%% API
-export([start_link/0, testServer/0]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
     terminate/2, code_change/3]).

-define(SERVER, ?MODULE).

-record(state, {}).

%%%===================================================================
%%% API
%%%===================================================================

testServer() ->
    gen_server:call(?MODULE, {test, test}).


%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @spec start_link() -> {ok, Pid} | ignore | {error, Error}
%% @end
%%--------------------------------------------------------------------
start_link() ->
    gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).

%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initializes the server
%%
%% @spec init(Args) -> {ok, State} |
%%                     {ok, State, Timeout} |
%%                     ignore |
%%                     {stop, Reason}
%% @end
%%--------------------------------------------------------------------
init([]) ->
    %% Note we must set trap_exit = true if we want
    %% terminate/2 to be called when the application is stopped
    process_flag(trap_exit, true),
    %MainGamePid = gameSystem:start(),

    io:format("~p starting~n", [?MODULE]),
    {ok, #state{}}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @spec handle_call(Request, From, State) ->
%%                                   {reply, Reply, State} |
%%                                   {reply, Reply, State, Timeout} |
%%                                   {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, Reply, State} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_call({test, test}, _From, State) ->
    io:format("TEST TEST TEST ~n"),
    Reply = ok,
    {reply, Reply, State};
handle_call(_Request, _From, State) ->
    Reply = ok,
    {reply, Reply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @spec handle_cast(Msg, State) -> {noreply, State} |
%%                                  {noreply, State, Timeout} |
%%                                  {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_cast(_Msg, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, State) -> {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
    ok.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%%%===================================================================
%%% Internal functions
%%%===================================================================

sRPG_event_handler.erl

-module(sRPG_event_handler).

-behaviour(gen_event).

%% API
-export([start_link/0, add_handler/0]).

%% gen_event callbacks
-export([init/1, handle_event/2, handle_call/2, 
     handle_info/2, terminate/2, code_change/3]).

-define(SERVER, ?MODULE).

-record(state, {}).

%%%===================================================================
%%% gen_event callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Creates an event manager
%%
%% @spec start_link() -> {ok, Pid} | {error, Error}
%% @end
%%--------------------------------------------------------------------
start_link() ->
    gen_event:start_link({local, ?SERVER}).

%%--------------------------------------------------------------------
%% @doc
%% Adds an event handler
%%
%% @spec add_handler() -> ok | {'EXIT', Reason} | term()
%% @end
%%--------------------------------------------------------------------
add_handler() ->
    gen_event:add_handler(?SERVER, ?MODULE, []).

%%%===================================================================
%%% gen_event callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever a new event handler is added to an event manager,
%% this function is called to initialize the event handler.
%%
%% @spec init(Args) -> {ok, State}
%% @end
%%--------------------------------------------------------------------
init([]) ->
    io:format("*** sRPG Event Handler init ***~n"),
    {ok, #state{}};
init(Args) ->
    io:format("*** sRPG Event Handler init: ~p~n", [Args]),
    {ok, #state{}}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever an event manager receives an event sent using
%% gen_event:notify/2 or gen_event:sync_notify/2, this function is
%% called for each installed event handler to handle the event.
%%
%% @spec handle_event(Event, State) ->
%%                          {ok, State} |
%%                          {swap_handler, Args1, State1, Mod2, Args2} |
%%                          remove_handler
%% @end
%%--------------------------------------------------------------------
handle_event({set_alarm, testAlarm}, State) ->
    error_logger:error_msg("*** BEEP BOOP TEST ALARM ***~n"),
    {ok, State};
handle_event({clear_alarm, testAlarm}, State) ->
    error_logger:error_msg("*** Brrrrppp... Test Alarm Over ***~n"),
    {ok, State};
handle_event(_Event, State) ->
    {ok, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever an event manager receives a request sent using
%% gen_event:call/3,4, this function is called for the specified
%% event handler to handle the request.
%%
%% @spec handle_call(Request, State) ->
%%                   {ok, Reply, State} |
%%                   {swap_handler, Reply, Args1, State1, Mod2, Args2} |
%%                   {remove_handler, Reply}
%% @end
%%--------------------------------------------------------------------
handle_call(_Request, State) ->
    Reply = ok,
    {ok, Reply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called for each installed event handler when
%% an event manager receives any other message than an event or a
%% synchronous request (or a system message).
%%
%% @spec handle_info(Info, State) ->
%%                         {ok, State} |
%%                         {swap_handler, Args1, State1, Mod2, Args2} |
%%                         remove_handler
%% @end
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
    {ok, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever an event handler is deleted from an event manager, this
%% function is called. It should be the opposite of Module:init/1 and
%% do any necessary cleaning up.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
    ok.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%%%===================================================================
%%% Internal functions
%%%===================================================================

以下是发生的事情的例子:

Eshell V6.3  (abort with ^G)
1> sRPG_supervisor:start_link().
** exception exit: noproc
2> sRPG_supervisor:start_in_shell_for_testing().
** exception exit: noproc
3> ServPid = sRPG_server:start_link().
sRPG_server starting
{ok,<0.39.0>}
4> gen_server:call(sRPG_server, {test, test}).
TEST TEST TEST 
ok

正如您所看到的,在没有主管的情况下调用服务器时可以正常工作。

我一直在努力研究其他人遇到的类似问题,但无济于事。

1 个答案:

答案 0 :(得分:1)

除非sasl应用程序正在运行,否则也不会运行alarm_handler,因此您的主管noproc中会出现init异常。试试这个:

1> application:start(sasl).
ok
2> sRPG_supervisor:start_in_shell_for_testing().
*** sRPG Event Handler init: {xyz,{alarm_handler,[]}}
sRPG_server starting

=PROGRESS REPORT==== 12-Aug-2015::17:00:49 ===
          supervisor: {local,sRPG_supervisor}
             started: [{pid,<0.71.0>},
                       {id,sRPG_server},
                       {mfargs,{sRPG_server,start_link,[]}},
                       {restart_type,permanent},
                       {shutdown,2000},
                       {child_type,worker}]
true