How to configure log4net programmatically from scratch (no config)

Question

This is a Bad Idea, I know, but... I want to configure log4net programmatically from scratch with no config file. I'm working on a simple logging application for me and my team to use for a bunch of relatively small departmental applications we're responsible for. I want them to all log to the same database. The logging application is just a wrapper around log4net with the AdoNetAppender preconfigured.

All of the applications are ClickOnce deployed, which presents a small problem with deploying the config file. If the config file were part of the core project, I could set its properties to deploy with the assembly. But it's part of a linked application, so I don't have the option of deploying it with the main application. (If that's not true, somebody please let me know).

Probably because it's a Bad Idea, there doesn't seem to be much sample code available for programmatically configruating log4net from scratch. Here's what I have so far.

Dim apndr As New AdoNetAppender()
apndr.CommandText = "INSERT INTO LOG_ENTRY (LOG_DTM, LOG_LEVEL, LOGGER, MESSAGE, PROGRAM, USER_ID, MACHINE, EXCEPTION) VALUES (@log_date, @log_level, @logger, @message, @program, @user, @machine, @exception)"
apndr.ConnectionString = connectionString
apndr.ConnectionType = "System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
apndr.CommandType = CommandType.Text
Dim logDate As New AdoNetAppenderParameter()
logDate.ParameterName = "@log_date"
logDate.DbType = DbType.DateTime
logDate.Layout = New RawTimeStampLayout()
apndr.AddParameter(logDate)
Dim logLevel As New AdoNetAppenderParameter()
logLevel.ParameterName = "@log_level"
'And so forth...

After configuring all the parameters for apndr, I at first tried this...

Dim hier As Hierarchy = DirectCast(LogManager.GetRepository(), Hierarchy)
hier.Root.AddAppender(apndr)

It didn't work. Then, as a shot in the dark, I tried this instead.

BasicConfigurator.Configure(apndr)

That didn't work either. Does anybody have any good references on how to configure log4net programmatically from scratch with no config file?

Answer 1

One way I've done this in the past is to include the configuration file as an embedded resource, and just used log4net.Config.Configure(Stream).

That way, I could use the configuration syntax I was familiar with, and didn't have to worry about getting a file deployed.

Answer 2

As Jonathan says, using a resource is a good solution.

It's a bit restrictive in that the embedded resource contents will be fixed at compile time. I have a logging component that generates an XmlDocument with a basic Log4Net configuration, using variables defined as appSettings (e.g. filename for a RollingFileAppender, default logging level, maybe connection string name if you want to use an AdoNetAppender). And then I call log4net.Config.XmlConfigurator.Configure to configure Log4Net using the root element of the generated XmlDocument.

Then administrators can customise the "standard" configuration by modifying a few appSettings (typically level, filename, ...) or can specify an external configuration file to get more control.

Answer 3

It is strange that BasicConfigurator.Configure(apndr) did not work. In my case it did its job... But, anyway, here goes the answer - you should've wrote hier.Configured = true; (c# code) after you've finished all setup.

Answer 4

Here's an example class that creates log4net config completely in code. I should mention that creating a logger via a static method is generally viewed as bad, but in my context, this is what I wanted. Regardless, you can carve up the code to meet your needs.

using log4net;
using log4net.Repository.Hierarchy;
using log4net.Core;
using log4net.Appender;
using log4net.Layout;

namespace dnservices.logging
{
public class Logger
{
 private PatternLayout _layout = new PatternLayout();
 private const string LOG_PATTERN = "%d [%t] %-5p %m%n";

 public string DefaultPattern
 {
  get { return LOG_PATTERN; }
 }

    public Logger()
    {
        _layout.ConversionPattern = DefaultPattern;
        _layout.ActivateOptions();
    }

    public PatternLayout DefaultLayout
    {
     get { return _layout; }
    }

    public void AddAppender(IAppender appender)
    {
        Hierarchy hierarchy = 
         (Hierarchy)LogManager.GetRepository();

        hierarchy.Root.AddAppender(appender);
    }

    static Logger()
    {
     Hierarchy hierarchy = (Hierarchy)LogManager.GetRepository();
        TraceAppender tracer = new TraceAppender();
        PatternLayout patternLayout = new PatternLayout();

        patternLayout.ConversionPattern = LOG_PATTERN;
        patternLayout.ActivateOptions();

        tracer.Layout = patternLayout;
        tracer.ActivateOptions();
        hierarchy.Root.AddAppender(tracer);

        RollingFileAppender roller = new RollingFileAppender();
        roller.Layout = patternLayout;
        roller.AppendToFile = true;
        roller.RollingStyle = RollingFileAppender.RollingMode.Size;
        roller.MaxSizeRollBackups = 4;
        roller.MaximumFileSize = "100KB";
        roller.StaticLogFileName = true;
        roller.File = "dnservices.txt";
        roller.ActivateOptions();
        hierarchy.Root.AddAppender(roller);

        hierarchy.Root.Level = Level.All;
        hierarchy.Configured = true;
    }

    public static ILog Create()
    {
        return LogManager.GetLogger("dnservices");
    }
}

}

Answer 5

I can't tell in the question's code snippet if the "'And so forth..." includes the very important apndr.ActivateOptions() which is indicated in Todd Stout's answer. Without ActivateOptions() the Appender is inactive and will not do anything which could explain why it is failing.