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《Erlang程序设计》第十八章构造基于OTP的系统

2014-01-06 14:26 260 查看

第十八章构造基于OTP的系统

第十八章构造基于OTP的系统

18.1 通用的事件处理

18.2 错误日志

18.2.1 记录一个错误

18.2.2 配置错误日志

18.2.3 分析错误

18.3 警报管理

18.4 应用服务

18.4.1 素数服务

18.4.2 面积服务

18.5 监控树

18.6 启动整个系统

18.7 应用程序

18.8 文件系统的组织

18.9 应用程序监视器

18.10 进一步深入

第十八章构造基于OTP的系统

18.1 通用的事件处理

%% 创建一个注册名为Name的进程, 这个进程执行my_handler函数
make(Name) ->
register(Name, spawn(fun() ->my_handler(fun no_op/1) end)).

%% 等待事件处理
%% 如果是{event, _}类型则调用Fun处理
%% 如果是{add, _}类型则更新处理函数
my_handler(Fun) ->
receive
{add, Fun1} ->
my_handler(Fun1);
{event, Any} ->
(catch Fun(Any)),
my_handler(Fun)
end.

%% 更新Name进程的处理函数为Fun
add_handler(Name, Fun) ->Name ! {add, Fun}.

%% 向Name进程发送事件X
event(Name, X) ->Name ! {event, X}.

%% 事件处理函数, 什么都不做
no_op(_) ->void.

运行结果:

1> c(event_handler).
{ok,event_handler}
2> event_handler:make(errors).
true
3> event_handler:event(errors, hi).
{event,hi}

为处理程序添加一个简单的回调模块

-module(motor_controller).

-export([add_event_handler/0]).

%% 更新errors进程的处理函数
add_event_handler() ->
event_handler:add_handler(errors, fun controller/1).

%% 具体处理, 一些简单的输出
controller(too_hot) ->
io:format("Turn off the motor~n");
controller(X) ->
io:format("~w ignored event: ~p~n",[?MODULE, X]).

运行结果:

4> c(motor_controller).
{ok,motor_controller}
5> motor_controller:add_event_handler().
{add,#Fun<motor_controller.0.125151531>}
6> event_handler:event(errors, cool).
motor_controller ignored event: cool
{event,cool}
7> event_handler:event(errors, too_hot).
Turn off the motor
{event,too_hot}

从这个简单的例子可以看到Erlang的强大之处:非常延迟的绑定^_^, 正如作者所说:使用这个机制, 我们可以构造一个可以随着时间推移不断演化的系统, 而演化的过程无需停机, 甚至也不需要升级代码。

18.2 错误日志

错误日志的三种视角:如何调用函数记录错误日志; 如何配置错误日志的存储; 如何对错误日志进行分析。

18.2.1 记录一个错误

# 错误日志的API

# 向错误日志发送一个错误消息
# error_logger:error_msg(String) -> ok
8> error_logger:error_msg("An error has occurred\n").
ok
9>
=ERROR REPORT==== 8-Nov-2013::13:22:42 ===
An error has occurred

# 向错误日志发送一个带参数的错误消息
# error_logger:error_msg(Format, Data) -> ok
10> error_logger:error_msg("~s, An error has occurred\n", ["Joe"]).

=ERROR REPORT==== 8-Nov-2013::13:25:39 ===
Joe, An error has occurred
ok

# 向错误日志发送一个标准错误报告
# error_logger:error_report(Report) -> ok
# @type Report = [{Tag, Data} | term()] | string() | term()
# @type Tag = term()
# @type Data = term()
11> error_logger:error_report([{tag1, data1}, a_term, {tag2, data}]).

=ERROR REPORT==== 8-Nov-2013::13:29:14 ===
tag1: data1
a_term
tag2: data
ok

18.2.2 配置错误日志

1. 标准错误日志

# 适合程序开发的环境
$ erl -boot start_clean

# 适合产品化系统的环境
$ erl -boot start_sasl

2. 不进行配置的SASL

matrix@MBP:18 $ erl -boot start_sasl
Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]

=PROGRESS REPORT==== 8-Nov-2013::13:32:52 ===
supervisor: {local,sasl_safe_sup}
started: [{pid,<0.34.0>},
{name,alarm_handler},
{mfargs,{alarm_handler,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:32:52 ===
supervisor: {local,sasl_safe_sup}
started: [{pid,<0.35.0>},
{name,overload},
{mfargs,{overload,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:32:52 ===
supervisor: {local,sasl_sup}
started: [{pid,<0.33.0>},
{name,sasl_safe_sup},
{mfargs,
{supervisor,start_link,
[{local,sasl_safe_sup},sasl,safe]}},
{restart_type,permanent},
{shutdown,infinity},
{child_type,supervisor}]

=PROGRESS REPORT==== 8-Nov-2013::13:32:52 ===
supervisor: {local,sasl_sup}
started: [{pid,<0.36.0>},
{name,release_handler},
{mfargs,{release_handler,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:32:52 ===
application: sasl
started_at: nonode@nohost
Eshell V5.9.1  (abort with ^G)
1> error_logger:error_msg("This is an error\n").
ok
2>
=ERROR REPORT==== 8-Nov-2013::13:33:45 ===
This is an error

3. 控制记录何种日志

监管报告, 在监管进程启动或者停止被监管的进程时;进程报告, 每次OTP监管进程启动或者停止的时候;崩溃报告, 当被监管的进程退出时, 如果退出原因不是normal或者shutdown则产生此报告。

%% elog1.config
[{sasl, [{sasl_error_logger, false}]}].

运行结果:

matrix@MBP:18 $ erl -boot start_sasl -config elog1
Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.1  (abort with ^G)
1> error_logger:error_msg("This is an error\n").
ok

=ERROR REPORT==== 8-Nov-2013::13:40:09 ===
This is an error

4. 文本文件和shell

%% elog2.config
[{sasl, [{sasl_error_logger, {file, "/Users/matrix/Documents/Erlang/erlp/18/error_logs/THELOG"}}]}].

运行结果:

matrix@MBP:18 $ cat error_logs/THELOG

=PROGRESS REPORT==== 8-Nov-2013::13:45:27 ===
supervisor: {local,sasl_safe_sup}
started: [{pid,<0.35.0>},
{name,alarm_handler},
{mfargs,{alarm_handler,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:45:27 ===
supervisor: {local,sasl_safe_sup}
started: [{pid,<0.36.0>},
{name,overload},
{mfargs,{overload,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:45:27 ===
supervisor: {local,sasl_sup}
started: [{pid,<0.34.0>},
{name,sasl_safe_sup},
{mfargs,
{supervisor,start_link,
[{local,sasl_safe_sup},sasl,safe]}},
{restart_type,permanent},
{shutdown,infinity},
{child_type,supervisor}]

=PROGRESS REPORT==== 8-Nov-2013::13:45:27 ===
supervisor: {local,sasl_sup}
started: [{pid,<0.37.0>},
{name,release_handler},
{mfargs,{release_handler,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 8-Nov-2013::13:45:27 ===
application: sasl
started_at: nonode@nohost

5. 循环日志和shell

%% elog3.config
[{sasl, [
{sasl_error_logger, false},
%% 指定输出目录
{error_logger_mf_dir, "/Users/matrix/Documents/Erlang/erlp/18/error_logs"},
%% 指定单个文件最大值
{error_logger_mf_maxbytes, 10485760},
%% 指定文件最大数量
{error_logger_mf_maxfiles, 10}
]}].

运行后会在错误日志存储目录下发现已经生成了名字为1的日志文件。

6. 产品化环境

%% elog4.config
[{sasl, [
{sasl_error_logger, false},
%% 只记录错误日志
{errorlog_type, error},
%% 指定输出目录
{error_logger_mf_dir, "/Users/matrix/Documents/Erlang/erlp/18/error_logs"},
%% 指定单个文件最大值
{error_logger_mf_maxbytes, 10485760},
%% 指定文件最大数量
{error_logger_mf_maxfiles, 10}
]}].

18.2.3 分析错误

使用rb模块读取错误日志

18.3 警报管理

-module(my_alarm_handler).
-behaviour(gen_event).

%% 需要自定义的gen_event的回调函数
-export([init/1, handle_event/2, handle_call/2,
handle_info/2, terminate/2]).

%% 完成初始化, 必须返回{ok, State}
init(Args) ->
io:format("*** my_alarm_handler init:~p~n",[Args]),
{ok, 0}.

%% handle_event(Event, State) -> {ok, NewState}
%% 其中Event是形如{EventType, EventArgs}的元组
%% EventType可以是set_event或clear_event
%% EventArgs是用户提供的参数

%% 设置警报
handle_event({set_alarm, tooHot}, N) ->
error_logger:error_msg("*** Tell the Engineer to turn on the fan~n"),
{ok, N+1};

%% 清除警报
handle_event({clear_alarm, tooHot}, N) ->
error_logger:error_msg("*** Danger over. Turn off the fan~n"),
{ok, N};

%% 其它类型的警报
handle_event(Event, N) ->
io:format("*** unmatched event:~p~n",[Event]),
{ok, N}.

%% 其它需要实现的回调函数
handle_call(_Request, N) ->Reply = N, {ok, Reply,  N}.

handle_info(_Info, N)    ->{ok, N}.

terminate(_Reason, _N)   ->ok.

运行结果:

matrix@MBP:18 $ erl -boot start_sasl -config elog3
Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.1  (abort with ^G)
1> c(my_alarm_handler).
{ok,my_alarm_handler}

# 普通的警报
2> alarm_handler:set_alarm(tooHot).
ok
3>
=INFO REPORT==== 8-Nov-2013::14:02:43 ===
alarm_handler: {set,tooHot}

# 使用自定义的警报
3> gen_event:swap_handler(alarm_handler, {alarm_handler, swap}, {my_alarm_handler, xyz}).
*** my_alarm_handler init:{xyz,{alarm_handler,[tooHot]}}
ok

# 触发警报
4> alarm_handler:set_alarm(tooHot).

=ERROR REPORT==== 8-Nov-2013::14:03:51 ===
*** Tell the Engineer to turn on the fan
ok

# 清除警报
5> alarm_handler:clear_alarm(tooHot).

=ERROR REPORT==== 8-Nov-2013::14:04:07 ===
*** Danger over. Turn off the fan
ok

# 查看错误日志报告
6> rb:start([{max, 20}]).
rb: reading report...done.
rb: reading report...done.
rb: reading report...done.
{ok,<0.51.0>}
7> rb:list().
No                Type   Process       Date     Time
==                ====   =======       ====     ====
20            progress  <0.30.0> 2013-11-08 13:51:15
19            progress  <0.30.0> 2013-11-08 13:51:15
18            progress  <0.23.0> 2013-11-08 13:51:15
17               error  <0.24.0> 2013-11-08 13:51:25
16            progress  <0.30.0> 2013-11-08 13:55:08
15            progress  <0.30.0> 2013-11-08 13:55:08
14            progress  <0.30.0> 2013-11-08 13:55:08
13            progress  <0.30.0> 2013-11-08 13:55:08
12            progress  <0.23.0> 2013-11-08 13:55:08
11        crash_report        rb 2013-11-08 13:55:23
10               error  <0.24.0> 2013-11-08 13:56:16
9        crash_report        rb 2013-11-08 13:56:20
8            progress  <0.30.0> 2013-11-08 14:01:19
7            progress  <0.30.0> 2013-11-08 14:01:19
6            progress  <0.30.0> 2013-11-08 14:01:19
5            progress  <0.30.0> 2013-11-08 14:01:19
4            progress  <0.23.0> 2013-11-08 14:01:19
3         info_report  <0.30.0> 2013-11-08 14:02:43
2               error  <0.30.0> 2013-11-08 14:03:51
1               error  <0.30.0> 2013-11-08 14:04:07
ok
8> rb:show(1).

ERROR REPORT  <0.34.0>                                      2013-11-08 14:04:07
===============================================================================

*** Danger over. Turn off the fan
ok
9> rb:show(2).

ERROR REPORT  <0.34.0>                                      2013-11-08 14:03:51
===============================================================================

*** Tell the Engineer to turn on the fan
ok

18.4 应用服务

18.4.1 素数服务

使用gen_server模块快速生成代码, 然后添加获取素数的的方法, 并添加警报处理。

-module(prime_server).
-behaviour(gen_server).

-export([new_prime/1, start_link/0]).

%% 必须自定义实现的gen_server回调函数
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).

start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).

%% 生成素数的服务, 设置了超时时间
new_prime(N) ->
gen_server:call(?MODULE, {prime, N}, 20000).

init([]) ->
process_flag(trap_exit, true),
io:format("~p starting~n",[?MODULE]),
{ok, 0}.

handle_call({prime, K}, _From, N) ->
{reply, make_new_prime(K), N+1}.

handle_cast(_Msg, N)  ->{noreply, N}.

handle_info(_Info, N)  ->{noreply, N}.

terminate(_Reason, _N) ->
io:format("~p stopping~n",[?MODULE]),
ok.

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

%% 生成素数时添加了警报处理
make_new_prime(K) ->
if
K > 100 ->
alarm_handler:set_alarm(tooHot),
N = lib_primes:make_prime(K),
alarm_handler:clear_alarm(tooHot),
N;
true ->
lib_primes:make_prime(K)
end.

18.4.2 面积服务

与素数服务代码相差无几, 但是计算面积的函数对于长方形需要提供两个参数而 hadle_call({area, Thing}, …) 只提供了对一个参数的支持。

18.5 监控树

监控树有两种类型:one-for-one, 如果一个进程失效, 它的监控进程就会重启它; all-for-one, 如果一个进程失效, 所有的工作进程都会被终止, 然后被重启。

监控树的形式:

%% RestartStrategy可以是one-for-one或all-for-one
%% MaxRestarts, Time限定了在Time时间内最多可以重启MaxRestarts次, 否则将终止所有工作进程, 以防止出现死循环
init(...) ->
{ok, {RestartStrategy, MaxRestarts, Time},
[Worker1, Worker2, ...]}.

实现自己的监控树:

-module(sellaprime_supervisor).
-behaviour(supervisor).

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

%% 调用 supervisor:start_link 启动监控树, 将会调用自定义的init/1函数
start() ->
spawn(fun() ->
supervisor:start_link({local,?MODULE}, ?MODULE, _Arg = [])
end).

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

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

init([]) ->
%% 使用自定义的警报器
gen_event:swap_handler(alarm_handler,
{alarm_handler, swap},
{my_alarm_handler, xyz}),
%% {ok, {SupFlags, Children}}
%% SupFlags : {supervision_strategy(), maxR(), maxT()}
%% supervision_strategy() : one_for_one | one_for_all | simple_one_for_one
{ok, {{one_for_one, 3, 10},
%% Children : [ChildStartSpecification]
%% ChildStartSpecification : {internal_name(),
%%                            {module(), function(), args()},
%%                            shutdown_time(),
%%                            child_type(),
%%                            modules()}
[{tag1,
{area_server, start_link, []},
permanent,
10000,
worker,
[area_server]},
{tag2,
{prime_server, start_link, []},
permanent,
10000,
worker,
[prime_server]}
]}}.

18.6 启动整个系统

1> sellaprime_supervisor:start_in_shell_for_testing().
*** my_alarm_handler init:{xyz,error}
area_server starting
prime_server starting
true

# 正常计算面积
2> area_server:area({square, 10}).
100

# 错误的参数
3> area_server:area({rectangle, 10, 20}).
area_server stopping
area_server starting
** exception exit: {{function_clause,[{area_server,compute_area,
[{rectangle,10,20}],
[{file,"area_server.erl"},{line,44}]},
{area_server,handle_call,3,
[{file,"area_server.erl"},{line,32}]},
{gen_server,handle_msg,5,
[{file,"gen_server.erl"},{line,588}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,227}]}]},
{gen_server,call,[area_server,{area,{rectangle,10,20}}]}}
in function  gen_server:call/2 (gen_server.erl, line 180)
4>
=ERROR REPORT==== 8-Nov-2013::14:52:19 ===
** Generic server area_server terminating
** Last message in was {area,{rectangle,10,20}}
** When Server state == 1
** Reason for termination ==
** {function_clause,[{area_server,compute_area,
[{rectangle,10,20}],
[{file,"area_server.erl"},{line,44}]},
{area_server,handle_call,3,
[{file,"area_server.erl"},{line,32}]},
{gen_server,handle_msg,5,
[{file,"gen_server.erl"},{line,588}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,227}]}]}

# 求阶乘
5> prime_server:new_prime(20).
Generating a 20 digit prime .................................
46877940609417488267

# 触发警报
6> prime_server:new_prime(120).
Generating a 120 digit prime .
=ERROR REPORT==== 8-Nov-2013::14:58:22 ===
*** Tell the Engineer to turn on the fan

=ERROR REPORT==== 8-Nov-2013::14:58:22 ===
*** Tell the Engineer to turn on the fan
......................................

=ERROR REPORT==== 8-Nov-2013::14:58:22 ===
*** Danger over. Turn off the fan
296183949730132038037133059736194002935394554326329071373943691961695511107247366466697700357121237051115084833162714631

=ERROR REPORT==== 8-Nov-2013::14:58:22 ===
*** Danger over. Turn off the fan

# 查看错误日志报告
7> rb:start([{max, 20}]).
rb: reading report...done.
{ok,<0.96.0>}
8> rb:list().
No                Type       Process       Date     Time
==                ====       =======       ====     ====
20               error      <0.24.0> 2013-11-08 14:52:19
19        crash_report   area_server 2013-11-08 14:52:19
18   supervisor_report      <0.24.0> 2013-11-08 14:52:19
17            progress      <0.24.0> 2013-11-08 14:52:19
16               error      <0.24.0> 2013-11-08 14:53:17
15        crash_report  prime_server 2013-11-08 14:53:17
14   supervisor_report      <0.24.0> 2013-11-08 14:53:17
13            progress      <0.24.0> 2013-11-08 14:53:17
12               error      <0.24.0> 2013-11-08 14:54:48
11        crash_report  prime_server 2013-11-08 14:54:48
10   supervisor_report      <0.24.0> 2013-11-08 14:54:48
9            progress      <0.24.0> 2013-11-08 14:54:48
8               error      <0.24.0> 2013-11-08 14:57:28
7        crash_report  prime_server 2013-11-08 14:57:28
6   supervisor_report      <0.24.0> 2013-11-08 14:57:28
5            progress      <0.24.0> 2013-11-08 14:57:28
4               error      <0.30.0> 2013-11-08 14:58:22
3               error      <0.30.0> 2013-11-08 14:58:22
2               error      <0.30.0> 2013-11-08 14:58:22
1               error      <0.30.0> 2013-11-08 14:58:22
ok
9> rb:show(19).

CRASH REPORT  <0.56.0>                                      2013-11-08 14:52:19
===============================================================================
Crashing process
initial_call                              {area_server,init,['Argument__1']}
pid                                                                 <0.56.0>
registered_name                                                  area_server
error_info
{exit,
{function_clause,
[{area_server,compute_area,
[{rectangle,10,20}],
[{file,"area_server.erl"},{line,44}]},
{area_server,handle_call,3,
[{file,"area_server.erl"},{line,32}]},
{gen_server,handle_msg,5,
[{file,"gen_server.erl"},{line,588}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,227}]}]},
[{gen_server,terminate,6,[{file,"gen_server.erl"},{line,747}]},
{proc_lib,init_p_do_apply,3,
[{file,"proc_lib.erl"},{line,227}]}]}
ancestors                                   [sellaprime_supervisor,<0.43.0>]
messages                                                                  []
links                                                             [<0.55.0>]
dictionary                                                                []
trap_exit                                                               true
status                                                               running
heap_size                                                                610
stack_size                                                                24
reductions                                                               176

ok

18.7 应用程序

应用程序信息文件

%% 名称
{application, sellaprime,
%% 概述
[{description, "The Prime Number Shop"},
%% 版本
{vsn, "1.0"},
%% 包含的模块
{modules, [sellaprime_app, sellaprime_supervisor, area_server,
prime_server, lib_lin, lib_primes, my_alarm_handler]},
%% 注册进程
{registered,[area_server, prime_server, sellaprime_super]},
%% 依赖的应用程序
{applications, [kernel,stdlib]},
%% 模块
{mod, {sellaprime_app,[]}},
{start_phases, []}
]}.

应用程序回调模块

-module(sellaprime_app).
-behaviour(application).
-export([start/2, stop/1]).

start(_Type, StartArgs) ->
sellaprime_supervisor:start_link(StartArgs).

stop(_State) ->
ok.

运行结果:

# 显示加载的应用程序
1> application:loaded_applications().
[{kernel,"ERTS  CXC 138 10","2.15.1"},
{sasl,"SASL  CXC 138 11","2.2.1"},
{stdlib,"ERTS  CXC 138 10","1.18.1"}]

# 加载指定的应用程序
2> application:load(sellaprime).
ok
3> application:loaded_applications().
[{kernel,"ERTS  CXC 138 10","2.15.1"},
{sasl,"SASL  CXC 138 11","2.2.1"},
{stdlib,"ERTS  CXC 138 10","1.18.1"},
{sellaprime,"The Prime Number Shop","1.0"}]

# 启动应用程序
4> application:start(sellaprime).
*** my_alarm_handler init:{xyz,{alarm_handler,[]}}
area_server starting
prime_server starting
ok

# 停止应用程序
5> application:stop(sellaprime).
prime_server stopping
area_server stopping
ok
6>
=INFO REPORT==== 8-Nov-2013::15:12:35 ===
application: sellaprime
exited: stopped
type: temporary

# 卸载应用程序
7> application:unload(sellaprime).
ok
8> application:loaded_applications().
[{kernel,"ERTS  CXC 138 10","2.15.1"},
{sasl,"SASL  CXC 138 11","2.2.1"},
{stdlib,"ERTS  CXC 138 10","1.18.1"}]

18.8 文件系统的组织


文件	功能
area_server.erl	面积服务, gen_server回调
prime_server.erl	素数服务, gen_server回调
sellaprime_supervisor.erl	监控回调
sellaprime_app.erl	应用程序回调
my_alarm_handler.erl	gen_event的事件回调
sellaprime.app	应用程序规范
elog4.config	错误日志配置文件

18.9 应用程序监视器

使用appmon:start()启动图形界面的查看程序。

18.10 进一步深入

5.5.5版文档

gen_server, gen_event, supervisors

http://www.erlang.org/documentation/doc-5.5.5/pdf/design_principles-5.5.5.pdf

如何创建一个启动文件

http://www.erlang.org/documentation/doc-5.5.5/pdf/system_principles-5.5.5.pdf

应用程序监视器

http://www.erlang.org/documentation/doc-5.5.5/pdf/appmon-2.1.9.pdf

更多文档

http://www.erlang.org/documentation/

Date: 2013-12-07 10:51:32 CST

Author: matrix

matrix.lisp@gmail.com

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章节导航

《Erlang程序设计》第十八章 构造基于OTP的系统

第十八章 构造基于OTP的系统

Table of Contents

第十八章 构造基于OTP的系统

18.1 通用的事件处理

18.2 错误日志

18.2.1 记录一个错误

18.2.2 配置错误日志

18.2.3 分析错误

18.3 警报管理

18.4 应用服务

18.4.1 素数服务

18.4.2 面积服务

18.5 监控树

18.6 启动整个系统

18.7 应用程序

18.8 文件系统的组织

18.9 应用程序监视器

18.10 进一步深入

《Erlang程序设计》第十八章构造基于OTP的系统

第十八章构造基于OTP的系统

第十八章构造基于OTP的系统