.NET Core logging to PostgreSQL DB using NLog

Question

I trying to integrate logging to DB in .NET Core. I am able to set up NLog and log messages to SQL Server. It was quite easy. But When I tried to switch DB to PostgreSQL nothing seems to be logged.

Below is the code in startup.cs

 public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory = NpgsqlLogManager.LoggerFactory;
            loggerFactory.ConfigureNLog(@"NLog.config");
            loggerFactory.AddNLog();
        }

The line

loggerFactory = NpgsqlLogManager.LoggerFactory;

is because the NLog by default uses SqlClient for sql server. This will switch to use PostgreSql.

Content in my NLog.config

<?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="internal-nlog.txt">

  <targets>
    <!--<target xsi:type="File" name="allfile" fileName="${var:configDir}\nlog-all.log"
                layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|${message} ${exception}" />

    <target xsi:type="File" name="ownFile-web" fileName="${var:configDir}\nlog-own.log"
             layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|  ${message} ${exception}" />-->

    <target xsi:type="Null" name="blackhole" />

    <target name="database" xsi:type="Database" >

    <connectionString>User ID=test;Password=pwd;Host=XXX;Port=1234;Database=DummyDB;Pooling=true;</connectionString>


      <commandText>
        insert into logs (
        Application, Logged, Level, Message,
        Logger, CallSite, Exception
        ) values (
        @Application, @Logged, @Level, @Message,
        @Logger, @Callsite, @Exception
        );
      </commandText>
      <parameter name="@Application" layout="Test" />
      <parameter name="@Logged" layout="${date}" />
      <parameter name="@Logger" layout="${logger}" />
      <parameter name="@Callsite" layout="${callsite}" />
      <parameter name="@Exception" layout="${exception:format=tostring}" />
      <parameter name="@Message" layout="${message}" />
      <parameter name="@Level" layout="${level}" />
    </target>
  </targets>

  <rules>
    <logger name="*" minlevel="Trace" writeTo="database" />
    <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
  </rules>
</nlog>

No Exceptions are logged in internal log file(internal-nlog.txt).

Accessing Logger in Controllers.

  public class TestController : Controller
        {
            private ILogger _logger;
            public TestController(ILogger<TestController> logger)
            {
                _logger = logger;
            }

            [HttpGet]
            public void Test()
            {
                try
                {
                    throw new System.Exception("Random Exception");
                }
                catch (System.Exception ex)
                {
                    _logger.LogError("Log Something");
                }
            }
        }

Am I missing something?

Answer 1

In Nlog.config modify this info (add dbProvider="Npgsql.NpgsqlConnection, Npgsql)

<target name="database" xsi:type="Database"  dbProvider="Npgsql.NpgsqlConnection, Npgsql">

And use NuGet install Npgsql

Answer 2

This worked for me to write into file and PostgreSQL:

1. First I created an ASP.NET Core Web Application (.NET Core).

2. Then I installed from NuGet:

   • Npgsql 3.2.1
   • NLog.Web.AspNetCore 4.3.1

3. Modified the following files like this:

   a) project.json

   "buildOptions": {
       "emitEntryPoint": true,
       "preserveCompilationContext": true,
       "copyToOutput": {
           "includeFiles": [ "nlog.config" ]
       }
   },
   "publishOptions": {
       "include": [
           "wwwroot",
           "web.config",
           "nlog.config"
       ]
   }
   

   
   

   b) Startup.cs

   public class Startup
   {
       public Startup(IHostingEnvironment env)
       {
           env.ConfigureNLog("nlog.config");
       }
   
       public void ConfigureServices(IServiceCollection services)
       {
           services.AddMvc();
       }
   
       public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
       {
           loggerFactory.AddNLog();
           app.UseDeveloperExceptionPage();
           app.UseMvc();
           app.AddNLogWeb();
       }
   }
   

   
   

   c) nlog.config

   <?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">
   
     <!-- Load the ASP.NET Core plugin -->
     <extensions>
       <add assembly="NLog.Web.AspNetCore"/>
     </extensions>
   
     <!-- the targets to write to -->
     <targets>
       <target xsi:type="File" name="localFile" fileName="c:\\temp\\nlog-all-${shortdate}.log"
                layout="${longdate} ${level} ${message} ${logger} ${callsite} ${exception:format=tostring}" />
   
       <target name="database" xsi:type="Database">
         <dbProvider>Npgsql.NpgsqlConnection, Npgsql, Version=3.2.1.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7</dbProvider>
         <connectionString>Server=localhost;Port=5432;User Id=XXX;Password=XXX;Database=TestLog;</connectionString>
         <commandText>
           insert into "logs" ("Application", "Timestamp", "Level", "Message", "Logger", "CallSite", "Exception")
           values (:Application, :Timestamp, :Level, :Message, :Logger, :Callsite, :Exception);
         </commandText>
         <parameter name="@Application" layout="TestApp" />
         <parameter name="@Timestamp" layout="${longdate}" />
         <parameter name="@Level" layout="${level}" />
         <parameter name="@Message" layout="${message}" />
         <parameter name="@Logger" layout="${logger}" />
         <parameter name="@Callsite" layout="${callsite}" />
         <parameter name="@Exception" layout="${exception:format=tostring}" />
       </target>
   
       <!-- write to the void aka just remove -->
       <target xsi:type="Null" name="blackhole" />
     </targets>
   
     <!-- rules to map from logger name to target -->
     <rules>
       <!--All logs, including from Microsoft-->
       <logger name="*" minlevel="Debug" writeTo="database" />
       <logger name="*" minlevel="Debug" writeTo="localFile" />
   
       <!--Skip Microsoft logs and so log only own logs-->
       <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
     </rules>
   </nlog>
   

   
   

   d) Controller

   public class HomeController : Controller
   {
       ILogger<HomeController> _logger;
   
       public HomeController(ILogger<HomeController> logger)
       {
           _logger = logger;
       }
   
       [Route("home/test")]
       public IActionResult Test()
       {
           _logger.LogInformation("Logged test information from home controller.");
   
           return Ok("Ok");
       }
   }
   

References:
[1]. Getting started with ASP.NET Core (project.json)

Answer 3

Change your connectionString to this ;

<target name="database" xsi:type="Database"  connectionString="Server=XXX;Port=1234;User Id=test;Password=pwd;Database=DummyDB;">

and you should use npsql driver here : http://www.npgsql.org/