Log4Net with AdoNetAppender - nothing happens

Question

Description

I have a config file as a resource in my assembly and want to change the ConnectionString programmatically in my application.

I load the configuration using log.net.Config.XmlConfigurator.Configure .

I have some breakpoints and see that the configuration is loaded successfuly and the connectionstring is Data Source=localhost\SQLExpress;Initial Catalog=Log;Integrated Security=SSPI; (local SQLExpress).

Problem

Nothing happens, no exception and no log entry. Any ideas.

using (Stream stream = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream("MyNamespace.Properties.log4net.config"))
{ 
    // stream is NOT null
    log4net.Config.XmlConfigurator.Configure(stream);
}

Hierarchy hier = LogManager.GetRepository() as Hierarchy;

if (hier != null)
{
    //get ADONetAppender
    var adoAppender = (AdoNetAppender)hier.GetAppenders().Where(appender => appender.Name.Equals("AdoNetAppender", StringComparison.InvariantCultureIgnoreCase)).FirstOrDefault();

    if (adoAppender != null)
    {
        // update connectionstring
        adoAppender.ConnectionString = configuration.GetConnectionString(ConnectionStringNames.Log).ConnectionString;
        //refresh settings of appender
        adoAppender.ActivateOptions(); 
    }
}

ILog logger = LogManager.GetLogger("MyProject"); 
logger.Warn("Test");

content of the log.net.config file

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
  </configSections>

  <log4net>
    <appender name="AdoNetAppender" type="log4net.Appender.ADONetAppender">
      <bufferSize value="1" />
      <connectionType value="System.Data.SqlClient.SqlConnection, System.Data,
  Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
      <connectionString value="[we will set this automatically at runtime]" />
      <commandText value="INSERT INTO Log ([Date],[Level],[Logger],[Message],[Exception])
  VALUES (@log_date, @log_level, @logger, @message, @exception)" />
      <parameter>
        <parameterName value="@log_date" />
        <dbType value="DateTime" />
        <layout type="log4net.Layout.RawTimeStampLayout" />
      </parameter>
      <parameter>
        <parameterName value="@log_level" />
        <dbType value="String" />
        <size value="50" />
        <layout type="log4net.Layout.PatternLayout">
          <conversionPattern value="%p" />
        </layout>
      </parameter>
      <parameter>
        <parameterName value="@logger" />
        <dbType value="String" />
        <size value="255" />
        <layout type="log4net.Layout.PatternLayout">
          <conversionPattern value="%c" />
        </layout>
      </parameter>
      <parameter>
        <parameterName value="@message" />
        <dbType value="String" />
        <size value="4000" />
        <layout type="log4net.Layout.PatternLayout">
          <conversionPattern value="%m" />
        </layout>
      </parameter>
      <parameter>
        <parameterName value="@exception" />
        <dbType value="String" />
        <size value="2000" />
        <layout type="log4net.Layout.ExceptionLayout" />
      </parameter>
    </appender>

    <root>
      <level value="ALL" />
      <appender-ref ref="AdoNetAppender" />
    </root>
  </log4net>
</configuration>

Answer 1

You can debug log4net by hooking into the log4net DebugAppender:

Add a log4net app setting in your app.config file:

<appSettings>
  <!-- log4net configuration when running in debug mode. -->    
  <add key="log4net.Internal.Debug" value="true" />   
</appSettings>

Add a debug appender in the log4net config:

<appender name="DebugAppender" type="log4net.Appender.DebugAppender">
  <immediateFlush value="true" />
  <layout type="log4net.Layout.SimpleLayout" />
</appender>

Add the appender to the log4net config root:

<root>
  <level value="ALL" />
  <appender-ref ref="AdoNetAppender" />
  <appender-ref ref="DebugAppender" />
</root>

When you run your application, look in the output window of Visual Studio and you should see all the internal logging for log4net. If not, then the log4net config file is never loading.

Edit

If you can use a connection string from your app.config file, then remove the connection string from the log4net AdoNetAppender and just call the connection string by name:

<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
  <bufferSize value="1" />
  <!-- note: you can use the 4.0 assembly -->
  <connectionType value="System.Data.SqlClient.SqlConnection,
              System.Data, 
              Version=4.0.0.0, 
              Culture=neutral, 
              PublicKeyToken=b77a5c561934e089" />
  <!-- This will retrieve a connection string by name from the app.config -->
  <connectionStringName value="ConnectionStringNameFromAppConfig" />
  <!-- snip -->
</appender>

Answer 2

Here are some things that I tried that worked out for me...

• I wasn't seeing anything because my <appender-ref ref="AdoNetAppender" /> didn't properly reference my <appender name="AdoNetAppender" ... /> in the Web.config . The 'AdoNetAppender' names need to match.

• Added <bufferSize value="1" /> to the <appender name="AdoNetAppender" /> section of the Web.config

• I created a user account with a password on the SQL server instead of using windows authentication. Granted user access to perform selects and inserts on the table

• In Global.asax.cs I initialize log4net using log4net.Config.XmlConfigurator.Configure();

• In my C# code I instantiate a new adoAppender object and call logger.Info("save to db");

The documentation on Apache's website is helpful as well ... http://logging.apache.org/log4net/release/config-examples.html#MS%20SQL%20Server

Hope that saves somebody some time and frustration. Thanks!

Answer 3

I had a log.net configuration running for years, that stopped logging to database this spring 2022. I solved it by specifying: size value="7" to a DateTime2 database parameter in the log.net configuration. Type in database: datetime2(7), not null. Why size on that type suddenly is madatory in log.net I don't know.