NLog、ASP.NET Core 和 SQL - 服务器未找到或不可访问

Question

我一直在尝试获得一个使用 NLog 的 ASP.NET 核心站点。在我尝试写入 SQL 数据库之前，它工作正常。我试过本地数据库和 Azure 数据库——都遇到了同样的问题。我什至将 nlog table 添加到一个已知的数据库，该站点已经连接到该数据库（使用 EF）。

我正在使用 nuget 包：NLog.Web.AspNetCore

无论如何，我得到以下信息：

Error Error when writing to database. Exception: System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.

以下是我的配置方式（我尝试更改这些语句的顺序）：

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
            loggerFactory.AddNLog();
            app.AddNLogWeb();
            env.ConfigureNLog("nlog.config");
            LogManager.Configuration.Variables["connectionString"] = Configuration.GetConnectionString("DefaultConnection");
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseBrowserLink();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }
//etc...

这是我的 nlog 配置：

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      autoReload="true"
      internalLogLevel="Warn"
      internalLogFile="c:\temp\internal-nlog.txt">

  <!-- define various log targets -->
  <targets>
    <target name="db"
            xsi:type="Database"
            commandType="StoredProcedure"
            commandText="[dbo].[NLog_AddEntry_p]">
      <parameter name="@machineName"    layout="${machinename}" />
      <parameter name="@siteName"       layout="${iis-site-name}" />
      <parameter name="@logged"         layout="${date}" />
      <parameter name="@level"          layout="${level}" />
      <parameter name="@username"       layout="${aspnet-user-identity}" />
      <parameter name="@message"        layout="${message}" />
      <parameter name="@logger"         layout="${logger}" />
      <parameter name="@properties"     layout="${all-event-properties:separator=|}" />
      <parameter name="@serverName"     layout="${aspnet-request:serverVariable=SERVER_NAME}" />
      <parameter name="@port"           layout="${aspnet-request:serverVariable=SERVER_PORT}" />
      <parameter name="@url"            layout="${aspnet-request:serverVariable=HTTP_URL}" />
      <parameter name="@https"          layout="${when:inner=1:when='${aspnet-request:serverVariable=HTTPS}' == 'on'}${when:inner=0:when='${aspnet-request:serverVariable=HTTPS}' != 'on'}" />
      <parameter name="@serverAddress"  layout="${aspnet-request:serverVariable=LOCAL_ADDR}" />
      <parameter name="@remoteAddress"  layout="${aspnet-request:serverVariable=REMOTE_ADDR}:${aspnet-request:serverVariable=REMOTE_PORT}" />
      <parameter name="@callSite"       layout="${callsite}" />
      <parameter name="@exception"      layout="${exception:tostring}" />
    </target>
  </targets>

  <rules>
    <logger name="*" minlevel="Trace" writeTo="db" />
  </rules>
</nlog>

最后，这是我的 appsettings.json:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\projectsV13;Database=XXXX;Trusted_Connection=True;MultipleActiveResultSets=true",
  },
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    }
  }
}

Answer 1

首先，

ConnectionString 看起来不一样

如果你用的是Local，可以接受这个错误。但是如果你有服务器定义代码是这样的。

"ConnectionStrings": {  "DatabaseContext": "Server=(localdb)\mssqllocaldb;Database=NAME;Trusted_Connection=True;MultipleActiveResultSets=true"}

我认为：错误的第二个原因。也许您无法正确读取 connectionString。

Answer 2

您没有在数据库目标中使用变量 "connectionString"。

你还需要

<target name="db"
   .. 
   connectionString="${var:connectionString}"
>

NLog 中的变量不会自动绑定到目标。您需要在配置中设置和使用它们。

更新

自 NLog.Web.AspNetCore 4.8（NLog.Extensions.Logging 1.4 用于 .NET Core 控制台程序）您可以直接从 appSettings.json

中读取

<target name="db"
   .. 
   connectionString="${configsetting:name=ConnectionStrings.DefaultConnection}"
>

见docs

NLog、ASP.NET Core 和 SQL - 服务器未找到或不可访问

NLog, ASP.NET Core and SQL - The server was not found or was not accessible

sql-server

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asp.net-core