Web Api on Azure shows no error detail using 'return InternalServerError(ex)'

Question

My Web Api when run locally (in Release mode) will return any errors in this format:

{
    "Message": "An error has occurred.",
    "ExceptionMessage": "No text specified",
    "ExceptionType": "System.Exception",
    "StackTrace": null
}

But after deployment/publish to an Azure VM, only this remains:

{
    "Message": "An error has occurred."
}

API code:

try
{
    var msg = ...
    new MessageService().SaveMessage(msg)); // <-- does some checks; may throw.
    return Ok();
}
catch (Exception ex)
{
    return InternalServerError(ex);
}

I'd like it to be more detailed on Azure, like the local result.
Can this be achieved, and if so, how?

I already (temporarily) removed <compilation xdt:Transform="RemoveAttributes(debug)" /> from the <system.web> part of Web.Release.config, and then re-deployed, but that made no difference.

Or am I using the wrong approach/pattern?
Obviously technical details should be limited, but right now we get no details at all.

Answer 1

You could try adding the following to your Global.asax:

GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;

Note: I wouldn't recommend that you keep this setting on in a production environment.

Answer 2

If instead you use

GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Default; 

then you can use the system.webServer error switch e.g.

<system.webServer>
    <httpErrors errorMode="Detailed" existingResponse="PassThrough">
    </httpErrors>
</system.webServer>

Note the existingResponse attribute to preserve the error message.

Answer 3

I had the same problem, the post is three years old, things have changed a little. If you setup a new Azure Mobile App with Visual Studio 2017 there is no longer a Global.asax.cs. I searched for hours, where to put this IncludeErrorDetailPolicy. It won't work without that setting.

You do it in your Startup.MobileApp.cs:

  public partial class Startup
  {
        public static void ConfigureMobileApp(IAppBuilder app)
        {
            HttpConfiguration config = new HttpConfiguration();

            config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;

            new MobileAppConfiguration()
                .UseDefaultConfiguration()
                .ApplyTo(config);

Don't forget, in your Web.config you also need to set:

<system.webServer>
    <httpErrors errorMode="Detailed" existingResponse="PassThrough">
    </httpErrors>
</system.webServer>

Don't use that for production environment!