How to setup ELMAH in asp.net solution

Question

I am new to ELMAH Error Logging. I have tried different option but didn't work. Following is my solution project structure. I am using ELMAH.MVC nugget package.

xyz.sol

xyz.web (mvc project)

xyz.Service  (class librarry)

xyz.Data (DAL)

xyz.Model (model classes)

I have setup ELMAH in xyz.web (MVC project) and it works fine with basic testing ie. 404 error. I can see that error logged and also in url www.project-name.com/ELmah

But, I want to use ELMAH in all other class library too (Service & Data). When something fails in service layer that error never got logged in the ElMAH. I was under impression that ELMAH.mvc nuget package log all handled and unhanded exception by itself. It seems that i might be missing in configuration or i might have to configure ELMAH in class library project too.

Please advise.

Thanks

---

Following my global handle error filter. It reaches to OnException but never reaches to LogException Method as "RaiseErrorSignal" method always returns true. Can you please advise me what am i doing wrong?

<code>
    public class ElmahHandleErrorAttribute : System.Web.Mvc.HandleErrorAttribute
    {
        private static ErrorFilterConfiguration _config;

    public override void OnException(ExceptionContext context)
    {
        base.OnException(context);

        if (!context.ExceptionHandled) // if unhandled, will be logged anyhow
            return;

        var e = context.Exception;
        var httpContext = context.HttpContext.ApplicationInstance.Context;
        if (httpContext != null &&
            (RaiseErrorSignal(e, httpContext) // prefer signaling, if possible
             || IsFiltered(e, httpContext))) // filtered?
            return;

        LogException(e, httpContext);
    }

    private static bool RaiseErrorSignal(Exception e, HttpContext context)
    {
        var signal = ErrorSignal.FromContext(context);
        if (signal == null)
            return false;
        signal.Raise(e, context);
        return true;
    }

    private static bool IsFiltered(Exception e, HttpContext context)
    {
        if (_config == null)
        {
            _config = context.GetSection("elmah/errorFilter") 
                                            as  ErrorFilterConfiguration
                      ?? new ErrorFilterConfiguration();
        }

        var testContext = new ErrorFilterModule.AssertionHelperContext(e, context);
        return _config.Assertion.Test(testContext);
    }

    private static void LogException(Exception e, HttpContext context)
    {
        ErrorLog.GetDefault(context).Log(new Error(e, context));
    }
}
</code>