How to override Elmah applicationname set in Web.config - asp.net-mvc

Question

We have a multi-tenanted MVC app, meaning that exactly the same app is published to multiple IIS virtual directories / applications, and then the app its self works out who it is, and skins its self (css) accordingly.
This is all very well, but anything logged by ELMAH in our elmah database gets logged under the same applicationName, as this is pulled out of Web.Config elmah section below where everything would be logged as "MyappName" :
<configuration>
[...]
<elmah>
<security allowRemoteAccess="false" />
<errorLog
type="Elmah.SqlErrorLog, Elmah"
connectionStringName="elmah"
applicationName="MyappName" />
</elmah>
</configuration>
The question is therefore how to override the applicationName setting from web.config with something specific so we can distinguish errors for a given tenant web site.

Answer 1

As this is configurable within the web.config, ELMAH are already providing you with a way to specify the application name when the application is deployed to different locations - it's just a case of making use of it.
This would generally be something that you would manipulate as part of your deployment steps. If you are doing it manually then it's going to be a pain, but it could be easily manipulated by using a web.config transform.
<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<elmah>
<errorLog applicationName="MyappName" xdt:Transform="SetAttributes" xdt:Locator="Match(name)" />
</elmah>
</configuration>
I wonder if the following might work, if you put the following into your Global.asax:
var service = ServiceCenter.Current;
ServiceCenter.Current = context =>
{
var connectionString = "YOUR CONNECTION STRING";
var container = new ServiceContainer(service(context));
var log = new SqlErrorLog(connectionString) { ApplicationName = "APP NAME HERE" };
container.AddService(typeof(ErrorLog), log);
return container;
};