目录

前言

什么是结构化呢? 结构化,就是将原本没有规律的东西进行有规律话。

就比如我们学习数据结构,需要学习排序然后又要学习查询,说白了这就是一套,没有排序,谈如何查询是没有意义的,因为查询算法就是根据某种规律得到最佳的效果。

同样日志结构话,能够让我们得到一些好处。如果说容易检索,容易分析,总的来说就是让我们的日志更加有规律。

如果我们的日志结构化了,那么可以使用elasticsearch 这样的框架进行二次整理,再借助一些分析工具。

我们就能做到可视化分析系统的运行情况,做到日志告警、上下文关联、实现追踪系统集成,同样也易于检索相关信息。

说了这么多,其实对于程序员,就是为了节约排查错误的时间,然后在做系统稳定化方案的时候有依据,我们是讲道理的,做事要有依据,不能张口就来。

正文

这里结构化,借助需要借助serilog,引用serilog.aspnetcore。

开源地址如下:

这里介绍一下简单的接入方式:

在createhostbuilder 中加入useserilog:

public static ihostbuilder createhostbuilder(string[] args) =>
	host.createdefaultbuilder(args)
		.configurewebhostdefaults(webbuilder =>
		{
			webbuilder.usestartup<startup>();
		}).useserilog(dispose:true);

然后在startup的configureservices的加入:

services.addlogserilog(configuration);

这个addlogserilog 是我写的扩展:

public static class serilogextension
{
    public static serilog.ilogger addlogserilog(this iservicecollection services, iconfiguration configuration)
    {
        log.logger = new loggerconfiguration().readfrom.configuration(configuration)
            .minimumlevel.debug()
            .enrich.fromlogcontext()
            .writeto.console(new renderedcompactjsonformatter())
            .writeto.file(formatter: new compactjsonformatter(), "logs\\test.txt", rollinginterval: rollinginterval.day)
            .createlogger();
        return log.logger;
    }
}

输出:

这时候发现我们的输出都json化了。

同时在根目录下的logs目录下输出日志文件:

但是我们这样发现,日志太多了,我们需要过滤掉一些日志,那么我们可以配置:

"serilog": {
    "minimumlevel": {
      "default": "information",
      "override": {
        "microsoft": "error",
        "system": "information" 
      }
    }
  }

测试代码:

[httpget]
public int getservice([fromservices]iselfservice selfservice)
{
	_logger.loginformation("hello word");
	return 1;
}

结果:

因为上面配置了microsoft 为error级别的,故而系统打印的日志只有error基本才会输出。

这里面简单看一下serilog 的原理,

因为已经介绍了日志系统的基本结果,故而直接往下续:

查看useserilog:

public static ihostbuilder useserilog(
  this ihostbuilder builder,
  ilogger logger = null,
  bool dispose = false,
  loggerprovidercollection providers = null)
{
  if (builder == null)
	throw new argumentnullexception(nameof (builder));
  builder.configureservices((action<hostbuildercontext, iservicecollection>) ((_, collection) =>
  {
	if (providers != null)
	  servicecollectionserviceextensions.addsingleton<iloggerfactory>(collection, (func<iserviceprovider, m0>) (services =>
	  {
		serilogloggerfactory serilogloggerfactory = new serilogloggerfactory(logger, dispose, providers);
		foreach (iloggerprovider service in (ienumerable<iloggerprovider>) serviceproviderserviceextensions.getservices<iloggerprovider>(services))
		  serilogloggerfactory.addprovider(service);
		return (iloggerfactory) serilogloggerfactory;
	  }));
	else
	  servicecollectionserviceextensions.addsingleton<iloggerfactory>(collection, (func<iserviceprovider, m0>) (services => (iloggerfactory) new serilogloggerfactory(logger, dispose, (loggerprovidercollection) null)));
	seriloghostbuilderextensions.configureservices(collection, logger);
  }));
  return builder;
}

这里我简单梳理一下日志系统的基本结构,首选是iloggerfactory, 里面会有一个createlogger,创建一个ilogger。那么这个ilogger的作用是什么呢?

是用来统一接口的。 比如说我们有文件日志,有控制台日志,有很多方式输出日志。那么就要有一个管理的来统一接口。

而每一种打印方式,继承iloggerprovider,比如consoleprovider继承iloggerprovider有一个createlogger方法,这个createlog才是创建具体的实现类,比如说consolelogger,consolelogger又继承ilogger。

从而ilogger的另一个实现类logger实现代理,管理其他继承ilogger的实现类。

可能我这样说有点模糊,那么请看完上面链接,应该就会明白我所以表达的意思。

那么回到上文中。

servicecollectionserviceextensions.addsingleton(collection, (func<iserviceprovider, m0>) (services => (iloggerfactory) new serilogloggerfactory(logger, dispose, (loggerprovidercollection)

将我们的iloggerfactory 替换成了serilogloggerfactory,官方是loggerfactory。

那么看下serilogloggerfactory:

public serilogloggerfactory(
  serilog.ilogger logger = null,
  bool dispose = false,
  loggerprovidercollection providercollection = null)
{
  this._provider = new serilogloggerprovider(logger, dispose);
  this._providercollection = providercollection;
}

/// <summary>disposes the provider.</summary>
public void dispose()
{
  this._provider.dispose();
}

/// <summary>
/// creates a new <see cref="t:microsoft.extensions.logging.ilogger" /> instance.
/// </summary>
/// <param name="categoryname">the category name for messages produced by the logger.</param>
/// <returns>
/// the <see cref="t:microsoft.extensions.logging.ilogger" />.
/// </returns>
public microsoft.extensions.logging.ilogger createlogger(string categoryname)
{
  return this._provider.createlogger(categoryname);
}

/// <summary>
/// adds an <see cref="t:microsoft.extensions.logging.iloggerprovider" /> to the logging system.
/// </summary>
/// <param name="provider">the <see cref="t:microsoft.extensions.logging.iloggerprovider" />.</param>
public void addprovider(iloggerprovider provider)
{
  if (provider == null)
	throw new argumentnullexception(nameof (provider));
  if (this._providercollection != null)
	this._providercollection.addprovider(provider);
  else
	selflog.writeline("ignoring added logger provider {0}", (object) provider, (object) null, (object) null);
}
}

那么继续查看createlogger,serilogloggerprovider的createlogger 及其相关:

private readonly serilog.ilogger _logger;
public serilogloggerprovider(serilog.ilogger logger = null, bool dispose = false)
{
   if (logger != null)
	this._logger = logger.forcontext((ienumerable<ilogeventenricher>) new serilogloggerprovider[1]
	{
	  this
	});
  if (!dispose)
	return;
  if (logger != null)
	this._dispose = (action) (() =>
	{
	  if (!(logger is idisposable disposable))
		return;
	  disposable.dispose();
	});
  else
	this._dispose = new action(log.closeandflush);
}
public microsoft.extensions.logging.ilogger createlogger(string name)
{
  return (microsoft.extensions.logging.ilogger) new seriloglogger(this, this._logger, name);
}

而seriloglogger 就是具体来管理全部继承ilogger具体的实现的类。 那么是否是和官方一样,其他实现类都是继承自ilogger的呢?答案不是,他们都继承自ilogeventsink,下面会继续提及,暂时不要关心这个。

同时要忘记官方每个实现具体打印的类继承ilogger,它的设计思想还是一样的,只是换了一个继承接口。

seriloglogger 里面继承microsoft.extensions.logging.ilogger,实现具体的打印的。

看下seriloglogger 的具体的部分,主要看log方法,因为这个实现打印的,这下面不用看太多,只需要看到其实里面是调用_logger的方法就行。

internal class seriloglogger : microsoft.extensions.logging.ilogger
  {
    private static readonly messagetemplateparser messagetemplateparser = new messagetemplateparser();
    private static readonly logeventproperty[] loweventidvalues = enumerable.range(0, 48).select<int, logeventproperty>((func<int, logeventproperty>) (n => new logeventproperty("id", (logeventpropertyvalue) new scalarvalue((object) n)))).toarray<logeventproperty>();
    private readonly serilogloggerprovider _provider;
    private readonly serilog.ilogger _logger;

    public seriloglogger(serilogloggerprovider provider, serilog.ilogger logger = null, string name = null)
    {
      serilogloggerprovider serilogloggerprovider = provider;
      if (serilogloggerprovider == null)
        throw new argumentnullexception(nameof (provider));
      this._provider = serilogloggerprovider;
      this._logger = logger;
      serilog.ilogger logger1 = this._logger;
      if (logger1 == null)
        logger1 = serilog.log.logger.forcontext((ienumerable<ilogeventenricher>) new serilogloggerprovider[1]
        {
          provider
        });
      this._logger = logger1;
      if (name == null)
        return;
      this._logger = this._logger.forcontext("sourcecontext", (object) name, false);
    }

    public bool isenabled(loglevel loglevel)
    {
      return this._logger.isenabled(levelconvert.toseriloglevel(loglevel));
    }

    public idisposable beginscope<tstate>(tstate state)
    {
      return this._provider.beginscope<tstate>(state);
    }

    public void log<tstate>(
      loglevel loglevel,
      eventid eventid,
      tstate state,
      exception exception,
      func<tstate, exception, string> formatter)
    {
      logeventlevel seriloglevel = levelconvert.toseriloglevel(loglevel);
      if (!this._logger.isenabled(seriloglevel))
        return;
      serilog.ilogger logger = this._logger;
      string str1 = (string) null;
      list<logeventproperty> logeventpropertylist = new list<logeventproperty>();
      if (state is ienumerable<keyvaluepair<string, object>> keyvaluepairs)
      {
        foreach (keyvaluepair<string, object> keyvaluepair in keyvaluepairs)
        {
          if (keyvaluepair.key == "{originalformat}" && keyvaluepair.value is string str2)
            str1 = str2;
          else if (keyvaluepair.key.startswith("@"))
          {
            logeventproperty property;
            if (logger.bindproperty(keyvaluepair.key.substring(1), keyvaluepair.value, true, out property))
              logeventpropertylist.add(property);
          }
          else
          {
            logeventproperty property;
            if (logger.bindproperty(keyvaluepair.key, keyvaluepair.value, false, out property))
              logeventpropertylist.add(property);
          }
        }
        type type = state.gettype();
        typeinfo typeinfo = type.gettypeinfo();
        if (str1 == null && !typeinfo.isgenerictype)
        {
          str1 = "{" + type.name + ":l}";
          logeventproperty property;
          if (logger.bindproperty(type.name, seriloglogger.asloggablevalue<tstate>(state, formatter), false, out property))
            logeventpropertylist.add(property);
        }
      }
      if (str1 == null)
      {
        string propertyname = (string) null;
        if ((object) state != null)
        {
          propertyname = "state";
          str1 = "{state:l}";
        }
        else if (formatter != null)
        {
          propertyname = "message";
          str1 = "{message:l}";
        }
        logeventproperty property;
        if (propertyname != null && logger.bindproperty(propertyname, seriloglogger.asloggablevalue<tstate>(state, formatter), false, out property))
          logeventpropertylist.add(property);
      }
      if (eventid.id != 0 || eventid.name != null)
        logeventpropertylist.add(seriloglogger.createeventidproperty(eventid));
      messagetemplate messagetemplate = seriloglogger.messagetemplateparser.parse(str1 ?? "");
      logevent logevent = new logevent(datetimeoffset.now, seriloglevel, exception, messagetemplate, (ienumerable<logeventproperty>) logeventpropertylist);
      logger.write(logevent);
    }
}

那么seriloglogger 的_logger 到底是什么呢?我们可以看到其实这个_logger 是serilogloggerfactory到serilogloggerprovider到seriloglogger一层一层传进去的,最后调用forcontext生成,上面可以看到具体各个的实例化函数。

如果我们不传的话,那么会默认使用 serilog.log.logger,在seriloglogger的实例化函数中这样写道:

serilog.ilogger logger1 = this._logger;
  if (logger1 == null)
	logger1 = serilog.log.logger.forcontext((ienumerable<ilogeventenricher>) new serilogloggerprovider[1]
	{
	  provider
	});
  this._logger = logger1;

而在useserilog中logger参数的参数介绍中也写道: the serilog logger; if not supplied, the static will be used.

之所以重点谈论这个_logger 这个数据,是为了引出serilog.log.logger这个东西,是不是感觉特别眼熟?我们在startup的configureservices中写道:

services.addlogserilog(configuration);

addlogserilog 为:

public static serilog.ilogger addlogserilog(this iservicecollection services, iconfiguration configuration)
{
	log.logger = new loggerconfiguration().readfrom.configuration(configuration)
		.minimumlevel.debug()
		.enrich.fromlogcontext()
		.writeto.console(new renderedcompactjsonformatter())
		.writeto.file(formatter: new compactjsonformatter(), "logs\\test.txt", rollinginterval: rollinginterval.day)
		.createlogger();
	return log.logger;
}

这里我们就生成了具体打印实现类的管理类,是代理模式哈。大体就是各个不同的实现类继承ilogeventsink,然后safeaggregatesink也继承自ilogeventsink,safeaggregatesink里面有个属性readonly ilogeventsink[] _sinks,然后调用serilog的 logger

类调用write方法会调用safeaggregatesink的emit。

safeaggregatesink类如下,主要看下emit方法:

class safeaggregatesink : ilogeventsink
{
	readonly ilogeventsink[] _sinks;

	public safeaggregatesink(ienumerable<ilogeventsink> sinks)
	{
		if (sinks == null) throw new argumentnullexception(nameof(sinks));
		_sinks = sinks.toarray();
	}

	public void emit(logevent logevent)
	{
		foreach (var sink in _sinks)
		{
			try
			{
                                // 调用不同的log打印的实现类 如文件、控制台 等
				sink.emit(logevent);
			}
			catch (exception ex)
			{
				selflog.writeline("caught exception while emitting to sink {0}: {1}", sink, ex);
			}
		}
	}
}

具体就不细写了,里面都是一些格式匹配的,根据我们上面的分析,其实我们应该知道先看createlogger这个函数哈,然后去看console这个函数。如对格式化感兴趣可

以去看下哈,里面又套了一层代理模式的娃。

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