1.特定进程集内的函数调用输入输出,收发消息------trace 指定Processes&＃xff5b;module,function,arity};
2.特定端口集的输入输出,收发消息---------------trace 指定ports。
• sys comes standard with OTP and allows to set custom tracing functions, log all kinds of events, and so on. It’s generally complete and fine to use for development. It suffers a bit in production because it doesn’t redirect IO to remote shells, and doesn’t have rate-limiting capabilities for trace messages. It is still recommended to read the documentationfor the module.• dbg also comes standard with Erlang/OTP. Its interface is a bit clunky in terms of usability, but it’s entirely good enough to do what you need. The problem with it is that you have to know what you’re doing, because dbg can log absolutely everything on the node and kill one in under two seconds.• tracing BIFs are available as part of the erlang module. They’re mostly the raw blocks used by all the applications mentioned in this list, but their lower level of abstraction makes them rather difficult to use.• redbug is a production-safe tracing library, part of the eper 5 suite. It has an internal rate-limiter, and a nice usable interface. To use it, you must however be willing to add in all of eper’s dependencies. The toolkit is fairly comprehensive and can be a very interesting install.• recon_trace is recon’s take on tracing. The objective was to allow the same levels of safety as with redbug, but without the dependencies. The interface is different, and the rate-limiting options aren’t entirely identical. It can also only trace function calls, and not messages.
1. 指定trace的进程集;
2. 指定模块中指定的函数的指定入参。
%%% _,--------,_ _,--------,_
%%% ,-&＃39; &＃96;-,,-&＃39; &＃96;-,
%%% ,-&＃39; ,-&＃39; &＃39;-, &＃96;-,
%%% | Matching -&＃39; &＃39;- Matching |
%%% | Pids | Getting | Trace |
%%% | | Traced | Patterns |
%%% | -, ,- |
%%% &＃39;-, &＃39;-, ,-&＃39; ,-&＃39;
%%% &＃39;-,_ _,-&＃39;&＃39;-,_ _,-&＃39;
%%% &＃39;--------&＃39; &＃39;--------&＃39;
%%%
1.先从指定模块&＃xff0c;函数&＃xff0c;和参数开始&＃xff1a;
> dbg:start(). % start dbg
> dbg:tracer(). % start a simple tracer process
> dbg:tp(Module, Function, Arity, []). % specify MFA you are interested in
> dbg:p(all, c). % trace calls (c) of that MFA for all processes.
... trace here
> dbg:stop_clear(). % stop tracer and clear effect of tp and p calls.
> dbg:tpl(Module, &＃39;_&＃39;, []). % all calls in Module
> dbg:tpl(Module, Function, &＃39;_&＃39;, []). % all calls to Module:Function with any arity.
> dbg:tpl(Module, Function, Arity, []). % all calls to Module:Function/Arity.
> dbg:tpl(M, F, A, [{&＃39;_&＃39;, [], [{return_trace}]}]). % same as before, but also show return value.
1> dbg:fun2ms(fun([M,N]) when N > 3 -> return_trace() end).
[{[&＃39;$1&＃39;,&＃39;$2&＃39;],[{&＃39;>&＃39;,&＃39;$2&＃39;,3}],[{return_trace}]}]
> dbg:p(all, c). % trace calls to selected functions by all functions
> dbg:p(new, c). % trace calls by processes spawned from now on
> dbg:p(Pid, c). % trace calls by given process
> dbg:p(Pid, [c, m]). % trace calls and messages of a given process
>dbg:tracer(port,dbg:trace_port(file,{"/log/trace",wrap,atom_to_list(node())})).
1.接口太过复杂&＃xff0c;使用步骤复杂&＃xff1a;start----》自定义的trace-----》stop;
2.没有输出日志次数控制&＃xff0c;在生产环境中使用不当时会导致异常&＃xff1a;不安全&＃xff01;
1.接口使用简单&＃xff0c;他只需要调用一个函数calls/2 calls/3就可以trace;
2. 有次数限制和速度限制;
3.输出的trace比的默认的trace易读性强。
参考资料
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