c# - 解析 nlog.config 时出现 NLog 异常 - 找不到目标 : 'EventLog'

Question

我正在 Visual Studio 2017 上开发一个 C# .NET Core 2.2 Web-Api。 我像 github 中描述的那样实现 NLog 4.6.1 . 当我使用 IIS 启动我的应用程序时，NLog 不会写入 Elasticsearch。 错误发生在 program.cs 的行

var logger = NLog.Web.NLogBuilder.ConfigureNLog("NLog.config").GetCurrentClassLogger();

我在NLogError.log 中发现一条错误消息:

2019-06-12 09:00:49.1606 Error Penter code herearsing configuration from NLog.config failed. Exception: NLog.NLogConfigurationException: Exception when parsing NLog.config.  ---> System.ArgumentException: Target cannot be found: 'EventLog'
   at NLog.Config.Factory`2.CreateInstance(String itemName)
   at NLog.Config.LoggingConfigurationParser.ParseTargetsElement(ILoggingConfigurationElement targetsElement)
   at NLog.Config.LoggingConfigurationParser.ParseNLogSection(ILoggingConfigurationElement configSection)
   at NLog.Config.LoggingConfigurationParser.LoadConfig(ILoggingConfigurationElement nlogConfig, String basePath)
   at NLog.Config.XmlLoggingConfiguration.ParseNLogElement(ILoggingConfigurationElement nlogElement, String filePath, Boolean autoReloadDefault)
   at NLog.Config.XmlLoggingConfiguration.Initialize(XmlReader reader, String fileName, Boolean ignoreErrors)
   --- End of inner exception stack trace ---

我试图缩短我的配置文件以避免其他问题，但仍然是同样的错误。目标“EventLog”就是在那里找到。

NLog.config:

<?xml version="1.0" encoding="utf-8" ?>
      <nlog autoReload="true" throwExceptions="false"
          internalLogLevel="Error" internalLogFile="NLogError.log"
          xmlns="http://www.nlog-project.org/schemas/NLog.xsd" 
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
          <targets>
            <target name="EventLog" xsi:type="EventLog"
              layout="${longdate} ${level} ${callsite} -> ${message} 
              ${exception:format=Message,StackTrace}"
              source="MonDBSvc" />
          </targets>
          <rules>
            <logger name="MonDbSvc" minlevel="Error" writeTo="EventLog" 
              log="Application" />
          </rules>
      </nlog>

NLog.config 文件和 program.cs 文件位于应用程序文件夹的同一根级别。

我尝试编写 NLog.config 和 nl og.config 用于文件名和上面的代码行。

是什么导致了这个解析问题？我可以尝试如何修复它？

感谢支持!

当我将日志级别从错误更改为警告时，我得到了一条更明确的消息。我确信 xml 作为 xml 是有效的。

2019-06-12 10:27:51.3735 Info Message Template Auto Format enabled
2019-06-12 10:27:51.4347 Error Parsing configuration from NLog.config failed. Exception: NLog.NLogConfigurationException: Exception when parsing NLog.config.  ---> System.ArgumentException: Target cannot be found: 'EventLog'
   at NLog.Config.Factory`2.CreateInstance(String itemName)
   at NLog.Config.LoggingConfigurationParser.ParseTargetsElement(ILoggingConfigurationElement targetsElement)
   at NLog.Config.LoggingConfigurationParser.ParseNLogSection(ILoggingConfigurationElement configSection)
   at NLog.Config.LoggingConfigurationParser.LoadConfig(ILoggingConfigurationElement nlogConfig, String basePath)
   at NLog.Config.XmlLoggingConfiguration.ParseNLogElement(ILoggingConfigurationElement nlogElement, String filePath, Boolean autoReloadDefault)
   at NLog.Config.XmlLoggingConfiguration.Initialize(XmlReader reader, String fileName, Boolean ignoreErrors)
   --- End of inner exception stack trace ---
2019-06-12 10:27:51.4347 Warn Failed loading config from NLog.config. Invalid XML?
2019-06-12 10:27:51.4597 Debug Watching path 'C:\Repositories\DataPicker\DataPicker\DataPicker.Api' filter 'NLog.config' for changes.
2019-06-12 10:27:51.4597 Debug --- NLog configuration dump ---
2019-06-12 10:27:51.4680 Debug Targets:
2019-06-12 10:27:51.4680 Debug Rules:
2019-06-12 10:27:51.4680 Debug --- End of NLog configuration dump ---
2019-06-12 10:27:51.4680 Trace FindReachableObject<System.Object>:
2019-06-12 10:27:51.4680 Info Found 0 configuration items
2019-06-12 10:27:51.4889 Debug Targets not configured for logger: DataPicker.Api.Program
2019-06-12 10:27:55.2679 Debug ScanAssembly('NLog.Web.AspNetCore, Version=4.0.0.0, Culture=neutral, PublicKeyToken=5120e14c03d0593c')
2019-06-12 10:27:55.7717 Debug Hide assemblies for callsite
2019-06-12 10:27:55.7717 Trace Assembly 'NLog.Extensions.Logging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=5120e14c03d0593c' will be hidden in callsite stacktrace
2019-06-12 10:27:55.7855 Debug ScanAssembly('NLog.Extensions.Logging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=5120e14c03d0593c')
2019-06-12 10:27:55.7855 Trace Assembly 'Microsoft.Extensions.Logging, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' will be hidden in callsite stacktrace
2019-06-12 10:27:55.7855 Trace Assembly 'Microsoft.Extensions.Logging.Abstractions, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' will be hidden in callsite stacktrace
2019-06-12 10:27:55.8068 Debug Targets not configured for logger: Microsoft.AspNetCore.Hosting.Internal.ApplicationLifetime
2019-06-12 10:27:55.8068 Debug Targets not configured for logger: Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv
2019-06-12 10:27:55.8178 Debug Targets not configured for logger: Microsoft.AspNetCore.Server.Kestrel
2019-06-12 10:27:55.8465 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.TypeForwardingActivator
2019-06-12 10:27:55.8465 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager
2019-06-12 10:27:55.8622 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.CngGcmAuthenticatedEncryptorFactory
2019-06-12 10:27:55.8622 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.CngCbcAuthenticatedEncryptorFactory
2019-06-12 10:27:55.8622 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ManagedAuthenticatedEncryptorFactory
2019-06-12 10:27:55.8776 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlEncryptor
2019-06-12 10:27:55.8776 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.Repositories.FileSystemXmlRepository
2019-06-12 10:27:55.9084 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.KeyManagement.DefaultKeyResolver
2019-06-12 10:27:55.9084 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingProvider
2019-06-12 10:27:55.9084 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.Internal.DataProtectionStartupFilter
2019-06-12 10:27:55.9835 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.XmlEncryption.DpapiXmlDecryptor
2019-06-12 10:27:56.1465 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Formatters.JsonPatchInputFormatter
2019-06-12 10:27:56.1465 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Formatters.JsonInputFormatter
2019-06-12 10:27:56.1674 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.RazorPages.Internal.RazorProjectPageRouteModelProvider
2019-06-12 10:27:56.2420 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker
2019-06-12 10:27:56.2524 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler
2019-06-12 10:27:56.2524 Debug Targets not configured for logger: Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector
2019-06-12 10:27:56.2707 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.ViewFeatures.CookieTempDataProvider
2019-06-12 10:27:56.2707 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.RazorPages.Internal.PageActionInvoker
2019-06-12 10:27:56.2814 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Internal.ActionSelector
2019-06-12 10:27:56.2814 Debug Targets not configured for logger: Microsoft.AspNetCore.Mvc.Internal.MvcRouteHandler
2019-06-12 10:27:56.2984 Debug Targets not configured for logger: Microsoft.AspNetCore.Builder.RouterMiddleware
2019-06-12 10:27:56.3256 Debug Targets not configured for logger: Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware
2019-06-12 10:27:56.3523 Debug Targets not configured for logger: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware
2019-06-12 10:27:56.3523 Debug Targets not configured for logger: Microsoft.AspNetCore.Server.IISIntegration.IISMiddleware
2019-06-12 10:27:56.3592 Debug Targets not configured for logger: Microsoft.AspNetCore.HttpOverrides.ForwardedHeadersMiddleware
2019-06-12 10:27:56.3592 Debug Targets not configured for logger: Microsoft.AspNetCore.Hosting.Internal.WebHost
2019-06-12 10:27:56.3783 Debug Targets not configured for logger: Microsoft.AspNetCore.Hosting.Internal.HostedServiceExecutor

Answer 1

关于找不到目标:“EventLog”错误

当无法实例化 Target 类时，将抛出“找不到目标”错误。由于您可以将目标插入 NLog，NLog 不知道哪些正手可用。另请注意，并非所有目标都适用于所有平台。

后者也是事件日志目标的情况——并非在所有平台上都可用:

参见 https://github.com/NLog/NLog/wiki/EventLog-target

Platforms Supported: Limited (Only available for Net35, Net40, Net45 and NetStandard 2.0. Note: NetStandard 2.0 must use NLog.WindowsEventLog package)

如果您使用的是 .NET Core 1.x，它将无法工作 - Microsoft 没有移植 API，因为事件日志仅适用于 Windows。

对于 .NET Core 2，您需要安装 NLog.WindowsEventLog打包并将其添加到您的 nlog.config(顶部):

<extensions>
    <add assembly="NLog.WindowsEventLog"/>
</extensions>

请注意:您发布的错误将表明目标不可用。配置似乎有效，记录器代码无需更改。 NLog.config 或 nlog.config 也不是问题。

Elasticsearch

也许我错过了，但为什么要使用 Elastic 搜索的事件日志目标？有一个 Elasticsearch 目标。包裹https://www.nuget.org/packages/NLog.Targets.ElasticSearch

此包支持 .NET Standard 1.3+ 和 .NET Standard 2+

用法:

<nlog>
  <extensions>
    <add assembly="NLog.Targets.ElasticSearch"/>
  </extensions>
  <targets>
    <target name="elastic" xsi:type="BufferingWrapper" flushTimeout="5000">
      <target xsi:type="ElasticSearch"/>
    </target>
  </targets>
  <rules>
    <logger name="*" minlevel="Info" writeTo="elastic" />
  </rules>
</nlog>