Erlang 中一些有用的系统函数

 对于运行的系统来说，很多情况下，需要检测进程和服务是否在运行，也要允许我们可以暂定和恢复进程与服务，sys模块提供了一组很有用的方法，简单的介绍下：

1. get_status(Name,Timeout) 查看指定进程名的运行状态

(ygzj_game2@127.0.0.1)41> sys:get_status(mod_carnival,1000).
{status,<0.642.0>,
        {module,gen_server},
        [[{rand_to_process,1},
          {random_seed,{3611,14663,29715}},
          {'$ancestors',[yg_server_sup,<0.47.0>]},
          {'$initial_call',{mod_carnival,init,1}}],
         suspended,<0.55.0>,[],
         [{header,"Status for generic server mod_carnival"},
          {data,[{"Status",suspended},
                 {"Parent",<0.55.0>},
                 {"Logged events",[]}]},
          {data,[{"State",{carnival_state,2068003,<<>>,0}}]}]]}

2.suspend(Name,Timeout) 暂停(挂起)进程和服务

(ygzj_game2@127.0.0.1)40> catch sys:suspend(mod_carnival,1000).
ok
(ygzj_game2@127.0.0.1)43> sys:get_status(mod_carnival,1000).
{status,<0.642.0>,
        {module,gen_server},
        [[{rand_to_process,1},
          {random_seed,{3611,14663,29715}},
          {'$ancestors',[yg_server_sup,<0.47.0>]},
          {'$initial_call',{mod_carnival,init,1}}],
         suspended,<0.55.0>,[],
         [{header,"Status for generic server mod_carnival"},
          {data,[{"Status",suspended},
                 {"Parent",<0.55.0>},
                 {"Logged events",[]}]},
          {data,[{"State",{carnival_state,2068003,<<>>,0}}]}]]}

3. resume(Name,Timeout) 恢复被挂起（暂停）的服务和进程

(ygzj_game2@127.0.0.1)44> catch sys:resume(mod_carnival,1000).
ok
(ygzj_game2@127.0.0.1)45> sys:get_status(mod_carnival,1000).
{status,<0.642.0>,
        {module,gen_server},
        [[{rand_to_process,undefined},
          {random_seed,{10979,6101,16140}},
          {'$ancestors',[yg_server_sup,<0.47.0>]},
          {'$initial_call',{mod_carnival,init,1}}],
         running,<0.55.0>,[],
         [{header,"Status for generic server mod_carnival"},
          {data,[{"Status",running},
                 {"Parent",<0.55.0>},
                 {"Logged events",[]}]},
          {data,[{"State",{carnival_state,2073234,<<>>,0}}]}]]}

这些系统函数，使我们对我们的进程具有更多的控制手段，赞一个。

最近好久没有写博客了，工作有些忙，精神状态也不是很好，像在走夜路一样，需要一点光，谁敢给我一点光么 ~_~!