Question

我一直在阅读 Erlang and OTP In Action 这本书，并在第4章中尝试构建OTP应用程序的源代码。

有一个gen_server具有这些回调方法（full source）：

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

init([Port]) ->
    {ok, LSock} = gen_tcp:listen(Port, [{active, true}]),
    {ok, #state{port = Port, lsock = LSock}, 0}.

handle_call(get_count, _From, State) ->
    {reply, {ok, State#state.request_count}, State}.

handle_cast(stop, State) ->
    {stop, normal, State}.

handle_info({tcp, Socket, RawData}, State) ->
    do_rpc(Socket, RawData),
    RequestCount = State#state.request_count,
    {noreply, State#state{request_count = RequestCount + 1}};
handle_info(timeout, #state{lsock = LSock} = State) ->
    {ok, _Sock} = gen_tcp:accept(LSock),
    {noreply, State}.

terminate(_Reason, _State) ->
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

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

主管init([])方法如下所示（full source）：

init([]) ->
    Server = {tr_server, {tr_server, start_link, []},
              permanent, 2000, worker, [tr_server]},
    Children = [Server],
    RestartStrategy = {one_for_one, 0, 1},
    {ok, {RestartStrategy, Children}}.

我已使用application:start(tcp_rpc)启动了该应用程序，然后将其移至应用程序中。当我退出telnet会话时，抛出了以下erlang错误：

=ERROR REPORT==== 11-Mar-2015::08:12:58 ===
** Generic server tr_server terminating 
** Last message in was {tcp_closed,#Port<0.733>}
** When Server state == {state,1055,#Port<0.725>,5}
** Reason for termination == 
** {function_clause,[{tr_server,handle_info,
                                [{tcp_closed,#Port<0.733>},
                                 {state,1055,#Port<0.725>,5}],
                                [{file,"src/tr_server.erl"},{line,87}]},
                     {gen_server,try_dispatch,4,
                                 [{file,"gen_server.erl"},{line,593}]},
                     {gen_server,handle_msg,5,
                                 [{file,"gen_server.erl"},{line,659}]},
                     {proc_lib,init_p_do_apply,3,
                               [{file,"proc_lib.erl"},{line,237}]}]}

=INFO REPORT==== 11-Mar-2015::08:12:58 ===
    application: tcp_rpc
    exited: shutdown
    type: temporary

我可以看到应用程序崩溃了，因为它没有tcp_closed的处理程序，但是我期望应用程序由主管重新启动，但它不是。

主管是否应该重新启动申请？

Answer 1

您必须将重启策略更改为

RestartStrategy = {one_for_one, 10, 1},

因为0,1表示app根本无法重启。

erlang otp应用程序在崩溃时不会重新启动

1 个答案: