Using Ninject to fill Log4Net Dependency

Question

I use Ninject as a DI Container in my application. In order to loosely couple to my logging library, I use an interface like this:

public interface ILogger
         


        

Answer 1

Bind<ILog>().ToMethod(x => LogManager.GetLogger(GetParentTypeName(x)))
            .InSingletonScope();

You are currently binding in Singleton scope, so only one logger is created which will use the name of the first one created. Instead use InTransientScope()

Answer 2

The Scope of ILog and ILogger needs to be Transient, otherwise it will just reuse the first logger that it creates. Thanks to @Meryln Morgan-Graham for helping me find that.

Answer 3

maybe my answer is late but I'm using this format:

private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<ILog>()
            .ToMethod(c => LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType))
            .InSingletonScope();
    }

Answer 4

I personally have no interest in abstracting away my logger, so my implementation modules reference log4net.dll directly and my constructors request an ILog as desired.

To achieve this, a one line registration using Ninject v3 looks like this at the end of my static void RegisterServices( IKernel kernel ):

        kernel.Bind<ILog>().ToMethod( context=> 
            LogManager.GetLogger( context.Request.Target.Member.ReflectedType ) );
        kernel.Get<LogCanary>();
    }

    class LogCanary
    {
        public LogCanary(ILog log)
        {
            log.Debug( "Debug Logging Canary message" );
            log.Info( "Logging Canary message" );
        }
    }

For ease of diagnosing logging issues, I stick the following at the start to get a non-DI driven message too:

public static class NinjectWebCommon
{
    public static void Start()
    {
        LogManager.GetLogger( typeof( NinjectWebCommon ) ).Info( "Start" );

Which yields the following on starting of the app:

<datetime> INFO  MeApp.App_Start.NinjectWebCommon           - Start
<datetime> DEBUG MeApp.App_Start.NinjectWebCommon+LogCanary - Debug Logging Canary message
<datetime> INFO  MeApp.App_Start.NinjectWebCommon+LogCanary - Logging Canary message

Answer 5

I do like the idea of wrapping the Log4Net in my own interfaces. I don't want to be dependent on Ninjects implementation, because to me that just means I take a dependency on Ninject throughout my application and I thought that was the exact opposite of what dependency injection is for. Decouple from third party services. So I took the original posters code but I changed the following code to make it work.

    private string GetParentTypeName(IContext context)
    {
        var res = context.Request.ParentRequest.ParentRequest.Service.FullName;
        return res.ToString();
    }

I have to call ParentRequest.ParentRequest so that when I print the layout %logger it will print the class that calls the Log4Net log method instead of the Log4Net class of the method that called the Log method.

Answer 6

For all of you that are still looking for the correct answer, the correct implementation is :

public class LoggingModule : NinjectModule
{
    public override void Load()
    {
        Bind<ILog>().ToMethod(x => LogManager.GetLogger(x.Request.Target.Member.DeclaringType));

        Bind<ILogger>().To<Log4NetLogger>()
            .InSingletonScope();
    }
}

Emphasis on:

x.Request.Target.Member.DeclaringType