Getting exception details from failing ASP.NET Core Configure() method in Azure

Question

I'm hosting an ASP.NET Core app in a Windows Azure Web Site. I'm wondering how to get details of an exception occuring in the Startup.Configure() method? All I see is An error occurred while starting the application..

One thing that DOES work is adding an app setting of ASPNETCORE_ENVIRONMENT="Development". Then I get System.Exception... at X.Startup.Configure() as expected.

But this is not a feasible solution. Azure is my Staging environment, and I'm already using the environment concept to substitute my connection strings (as suggested in almost every ASP.NET Core documentation I have ever read).

Things I have tried without any effect:

Adding app.UseDeveloperExceptionPage() (not surrounded by any if statement).
Adding <customErrors mode="Off"/> to Web.config, as suggested here https://stackoverflow.com/a/29539669/268091
Adding ASPNET_DETAILED_ERRORS="true" to Web.config, as suggested here https://stackoverflow.com/a/32094245/268091
Enabling Detailed error messages in Azure portal / Diagnostics logs
Adding a try-catch, writing a manual response, as suggested here https://stackoverflow.com/a/29524042/268091
Deleting everything and redeploying.

Is there really no other way to achieve this, than hijacking the environment concept altogether?

Have you seen this: http://stackoverflow.com/questions/29518365/how-to-get-error-details-of-an-asp-net-5-app-deployed-on-azure-websites?rq=1 ? — tymtam, Oct 25 '16 at 23:26
Maybe there is a way to implement it self using try...catch `try {...} catch (Exception ex) { var file = env.ContentRootPath+@"\wwwroot\startuperr.htm"; using (FileStream fs = new FileStream(file, FileMode.Append, FileAccess.Write)) using (StreamWriter sw = new StreamWriter(fs)) { sw.WriteLine( DateTime.UtcNow+":"+ex.Message + ex.StackTrace); } }` — Tom Sun - MSFT, Oct 26 '16 at 09:45
@TomSun Thanks, that could be a work-around if all else fails. — MEMark, Oct 26 '16 at 12:07

score 1 · Answer 1 · answered Oct 25 '16 at 23:25

I don't know if this would work for you, but we've decided to report these using Application Insights.

public void Configuration(IAppBuilder app)
{
    var ai = new Microsoft.ApplicationInsights.TelemetryClient();
    ai.TrackEvent("Application Starts");

    try
    {
    //Amazing code here
    }
    catch ( Exception ex )
    {
        ex = new Exception("Application start up failed.", ex);

        ai.TrackException(ex);
        throw;
    }
}

Getting exception details from failing ASP.NET Core Configure() method in Azure

1 Answers1