CODEWITHSUNDEEP
c#.netazureconfigurationsettings
Philip Pittle
Philip Pittle

Reputation: 12295

Azure Configuration Settings (cscfg) with fallback to a Settings.Setting file

Defining a configuration setting in an Azure ServiceConfiguration (.cscfg) is compelling because I can then change the value within the Azure portal.

However, as discussed here Microsoft.WindowsAzure.CloudConfigurationManager.GetSettings("Foo") will fall back to looking for a <appSettings> value in the app.config.

Is it possible to have it fallback to a Settings.setting file instead?

I could create a method like this, but is there a better/built-in way?

public T GetSetting<T>(string name, T defaultValue = null)
{
    return
        !RoleEnvironment.IsAvailable
        //we could be in a non azure emulated environment (ie unit test)
        ? defaultValue 
        : RoleEnvironemt.GetConfigurationSettingValue(name)  
          ??
          //in case no value is specified in .cscfg or <appSettings>
          defaultValue;
}

And then have to call it like:

var settings = GetSetting("Example", Properties.Settings.Default.Example);

But this is a pain that I have to specify the "Example" string parameter

Upvotes: 3

Views: 854

Answers (1)

Philip Pittle
Philip Pittle

Reputation: 12295

I ended up creating a new overload for the method above and was able to pull out the name of the setting from an Expression:

var setting = __cloudSettingsProvider.GetSetting(
   () => Properties.Setting.Default.ExampleConfiguration);

So now, I can pass in the setting name and default value. The method will check against Azure config, then appSettings, then applicationSettings and then finally the hard coded default in Settings.Settings.

Here's the code for the method (essentially):

public T GetSetting<T>(Expression<Func<T>> setting)
{
     var memberExpression = (MemberExpression) setting.Body;

     var settingName = memberExpression.Member.Name;

     if (string.IsNullOrEmpty(settingName))
         throw new Exception(
            "Failed to get Setting Name " + 
            "(ie Property Name) from Expression");

     var settingDefaultValue = setting.Compile().Invoke();

     //Use the method posted in the answer to try and retrieve the
     //setting from Azure / appSettings first, and fallback to 
     //defaultValue if no override was found
     return GetSetting(
            settingName,
            settingDefaultValue);
}

Upvotes: 1

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