Azure config - not connection string or app setting - azure

Question

When deploying a cloud service worker role to Azure, I always set the various connection strings and app settings/configuration settings via the cscfg files and then via the Azure web interface if they need to change at run time, which all works fine.
Is it possible to do something similar for configs which are not connection strings or app settings/configuration settings?
Specifically I have something similar to the following:
<log4net>
<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
<bufferSize value="1" />
<connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
<!-- This is the connection string I would like to store in Azure -->
<connectionString value="Server=tcp:azure.sql.server,1433;Database=MyAzureSqlDbName;User ID=my-user-name#my-server;Password=my-password;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;Application Name=log4net" />
<commandText value="INSERT INTO [MyLogTableName] ( [Date], [etc] ) VALUES ( #log_date, etc)" />
<parameter>
<parameterName value="#log_date" />
<dbType value="DateTime" />
<layout type="log4net.Layout.RawTimeStampLayout" />
</parameter>
</appender>
</log4net>
Is there any way of putting that connection string into cscfg files or Azure like my other settings? It's a pain to keep changing it manually in the app.config when I deploy, I keep forgetting (!) which means another re-deploy which is takes 4/5 minutes each time.
I can't use transforms btw as these settings are stored in app.config file of my worker role app and my understanding is that transforms only work with web.config files.

Answer 1

I think the easiest way will be for you to change the settings of the appender at runtime. If you add some logic in your global.asax.cs Application_Start method, you can change the connection string using the CloudConfigurationManager which will then either pull it from the cscfg or the app.config.
Steps would be:
add an appSetting in the app.config to hold the connection string you want to use when running locally
add a setting to your cscfg with the same name as your appSetting to hold the azure db connection string
install the Microsoft.WindowsAzure.ConfigurationManager nuget package if you don't already use it
Add the following code to your global.asax.cs Application_Start:
protected void Application_Start()
{
var hier = (Hierarchy)LogManager.GetRepository();
if (hier != null)
{
var appenders = hier.GetAppenders().OfType<AdoNetAppender>();
foreach (var appender in appenders)
{
appender.ConnectionString =
CloudConfigurationManager.GetSetting(connectionStringKey);
appender.ActivateOptions();
}
}
}
Two helpful links for you:
4 Tips for using Log4NET's ADONetAppender in ASP.NET
Changing Log4net Connection String at Runtime

Answer 2

The cscfg file is just name/value pairs, and is there for you to set any parameters you might need (specifically, ones you would like to be able to set/change without redeploying your app).
But more importantly: The only config file exposed externally is the .cscfg. You cannot arbitrarily access a different config file in the same way. You'd need to modify the config file yourself, based on cscfg changes. Alternatively, you can download your config file from somewhere (e.g. storage blob) on startup. This lets you modify a config, push to blob storage, and have your app download/use the new config (you'd just need to come up with a trigger mechanism to signal your role instances to re-initialize with the new config).