How to specify a constant parameter when using log4net AdoNetAppender

Question

http://logging.apache.org/log4net/release/config-examples.html

Given the log table:

CREATE TABLE [dbo].[Log] ( [Id] [int] IDENTITY (1, 1) NOT NULL, [Date] [datetime] NOT NULL, [Thread] [varchar] (255) NOT NULL, [Level] [varchar] (50) NOT NULL, [Logger] [varchar] (255) NOT NULL, [Message] [varchar] (4000) NOT NULL, [Exception] [varchar] (2000) NULL, [Product] [varchar] 100 not null ) 

and appender configuration here:

 <appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender"> <bufferSize value="100" /> <connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" /> <connectionString value="data source=[database server];initial catalog=[database name];integrated security=false;persist security info=True;User ID=[user];Password=[password]" /> <commandText value="INSERT INTO Log ([Date],[Thread],[Level],[Logger],[Message],[Exception], [Product]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception, @product)" /> <parameter> <parameterName value="@log_date" /> <dbType value="DateTime" /> <layout type="log4net.Layout.RawTimeStampLayout" /> </parameter> <parameter> <parameterName value="@thread" /> <dbType value="String" /> <size value="255" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%thread" /> </layout> </parameter> <parameter> <parameterName value="@log_level" /> <dbType value="String" /> <size value="50" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%level" /> </layout> </parameter> <parameter> <parameterName value="@logger" /> <dbType value="String" /> <size value="255" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%logger" /> </layout> </parameter> <parameter> <parameterName value="@message" /> <dbType value="String" /> <size value="4000" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%message" /> </layout> </parameter> <parameter> <parameterName value="@exception" /> <dbType value="String" /> <size value="2000" /> <layout type="log4net.Layout.ExceptionLayout" /> </parameter> </appender> 

How to add a constant parameter to the product column without any code changes? Changing the configuration is only possible!

For example, I want to do something like this:

 <parameter> <parameterName value="@product" /> <dbType value="String" /> <size value="100" /> <constantValue value="Product A" /> <!-- how do i do this? --> </parameter> 

EDIT: The answer is simple. Change the command text!

 <commandText value="INSERT INTO Log ([Date],[Thread],[Level],[Logger],[Message],[Exception], [Product]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception, 'Product A')" /> 

Answer 1

While you can simply add the value "SomeConstant" to the insert statement, we use the following method with AdoNetAppender. We add the @source column to our log table, so we can have many servers, all are logged in the same table, but give us some SYSLOG functionality.

  ... <commandText value="INSERT INTO Log ([Date],[Source],[Level],[Logger],[Message],[Exception]) VALUES (@log_date, @source, @log_level, @logger, @message, @exception)" /> ... <parameter> <parameterName value="@source"/> <dbType value="String"/> <size value="32"/> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="WEB1"/> </layout> </parameter> 

The PatternLayout readily accepts string constants, why is it difficult!

Enjoy.

Answer 2

I suppose you could do this:

 using System.IO; using log4net.Core; using log4net.Layout; namespace MyApp { public class ConstantLayout : LayoutSkeleton { public string Text { get; set; } public override void ActivateOptions() { } public override void Format(TextWriter writer, LoggingEvent loggingEvent) { using (writer) writer.Write(this.Text); } } } 

and then..

  <parameter> <parameterName value="@product" /> <dbType value="String" /> <size value="100" /> <layout type="MyApp.ConstantLayout"> <text value="Product A" /> </layout> </parameter>