elmah: exceptions without HttpContext?

Question

I spawn a thread on Application_Start and would like to log exceptions. There is no Context/HttpContext/HttpContext.Current, so how might I get it to log?

At the moment, it does not catch any exception in my threads and if I write ErrorSignal.FromCurrentContext().Raise(ex); I get an error about context cannot be null.

Maybe I can create a dummy HttpContext but somehow I don't think that will work well.

-edit- I tried ErrorSignal.Get(new HttpApplication()).Raise(ex); and it doesn't seem to pick up that exception.

Answer 1

Make sure you set your application name in web.config

<errorLog type="Elmah.SqlErrorLog, Elmah" 
          connectionStringName="nibWeb" 
          applicationName="Nib.Services" />

and then

ErrorLog.GetDefault(null).Log(new Error(error));

will work

Answer 2

I wasn't using <errorLog> as in Brendan Carey's answer because I was only in-memory logging. Nevertheless, his command worked great in my case without naming the application:

Elmah.ErrorLog.GetDefault(null).Log(new Elmah.Error(new Exception("The application has done something.")));

I DID have to recompile Elmah with .NET 4.0, because of an error about needing System.Web.Abstractions 3.5.0.0. My compiled-for-.NET 4.0 fork is here if anyone wants it (also strong naming):

http://code.google.com/r/scottstafford-elmah/

Answer 3

For my application, I saved this.Context.ApplicationInstance in Application_Start so that I can call Elmah.ErrorSignal.Get with the saved instance. With the ErrorSignal, I could then Raise. This goes through all the email filters.

Below is the code. I use FluentScheduler to

public class Global : HttpApplication {
    void Application_Start(object sender, EventArgs e) {

        var application = Context.ApplicationInstance;
        FluentScheduler.TaskManager.UnobservedTaskException +=
            (FluentScheduler.Model.TaskExceptionInformation i, UnhandledExceptionEventArgs a) =>
                Elmah.ErrorSignal.Get(application).Raise(i.Task.Exception);

    }
}

Answer 4

I added a solution to: Using ELMAH in a console application that adds ability to send email, tweets and filter in addition to logging.