Erlang中出错后自动重启演示：模拟supervisor behavior

本文介绍如何使用Erlang编程语言创建一个基于消息传递的简单系统，包括进程管理、请求响应机制和异常处理。通过实现一个Erlang模块，演示了如何创建进程、发送和接收消息，以及在不同消息类型下的响应处理。

代码：

-module(supervise).
-compile([export_all]).

start_process() ->
    spawn(?MODULE, restarter, []).

restarter() ->
    process_flag(trap_exit, true),
    Pid = spawn_link(?MODULE, response, []),
    register(process, Pid),
    receive
        {'EXIT', Pid, normal} ->
            ok;
        {'EXIT', Pid, shutdown} ->
            ok;
        {'EXIT', Pid, _} ->
            restarter()
    end.

request(Value) ->
    Ref = make_ref(),
    process ! {self(), Ref, {Value}},
    receive
        {Ref, Responses} -> Responses
    after 2000 ->
        timeout
    end.

response() ->
    receive
        {From, Ref, {"Hi"}} ->
            From ! {Ref, "Hi, How are you ?"};
        {From, Ref, {"Hello"}} ->
            From ! {Ref, "Hello, How is it going ?"};
        {From, Ref, {"Bye"}} ->
            From ! {Ref, "Bye Bye !"};
        {From, Ref, {Other}} ->
            From ! {Ref, Other ++ " is good"}
    end,
    response().

执行：

Eshell V5.10.3

(test@mbp-108-on-01)1> supervise:start_process().

<0.136.0>

(test@mbp-108-on-01)2> supervise:request("Hello").

"Hello, How is it going ?"

(test@mbp-108-on-01)3> whereis(process).

<0.137.0>

(test@mbp-108-on-01)4> supervise:request("Hi").

"Hi, How are you ?"

(test@mbp-108-on-01)5> whereis(process).

<0.137.0>