FeatureToggle.Azure

FeatureToggle.Azure is a collection of FeatureToggle providers for various Azure services. The providers support centralized storage of feature toggles in Azure. For more information on how to implement and leverage features toggles, using FeatureToggle, see the official docs for FeatureToggle

List of Providers

• FeatureToggle Provider for Azure DocumentDB, (learn more)
• FeatureToggle Provider for Azure Table storage, (learn more)
• FeatureToggle Provider for Service Fabric configuration packages, (learn more)

FeatureToggle.Azure.DocumentDB

FeatureToggle provider for storing feature toggles as simple json documents in Azure DocumentDB (part of Azure Cosmos DB). The nuget package can be found on nuget.org.

Getting started

1. Install FeatureToggle.Azure.DocumentDB from nuget into your project.
2. Configure DocumentDbProvider at application startup, such as in Global.asax or Startup.cs by specifying the DocumentDb service uri and authentication key needed to store and retreive features toggles in DocumentDB. Global.asax example:

protected void Application_Start()
{
    // other startup configuration
    DocumentDbProvider.Configure("https://[serviceuri]", "[authkey]");
}

3. Add a class to your project representing the feature that needs to be controlled, e.g. PrintFeature and inherit from DocumentDbToggle

public class PrintFeature : DocumentDbToggle
{
}

4. Use the new feature toggle in your code to isolate features.

public ActionResult Index()
{
    ViewBag.EnablePrint = Is<PrintFeature>.Enabled;
    return View();
}

5. Add a json document in DocumentDB, either using the Data Explorer in the Azure Portal or the standalone Azure Storage Explorer (ASE) or through the client API of DocumentDB in order to turn on/off the feature. The document looks like this:

{
   "id": "PrintFeature",
   "Enabled": false
}

Provider Configuration

In order to control how the DocumentDbProvider fetches feature toggles from DocumentDb, the provider can be configured through an instance of DocumentDbConfiguration passed to the overloaded static method DocumentDbProvider.Configure(docDbConfig).

The following options can be controlled through the configuration instance:

• AuthKey The authorization key for the Cosmos DB account.
• ServiceEndpoint The service endpoint for the Cosmos DB account.
• DatabaseId Database id (name) where toggles are stored. Defaults to FeatureToggle.
• CollectionId Document Collection id (name) where toggles are stored. Defaults to Toggles.
• AutoCreateDatabaseAndCollection Enable auto creation of database and collection for storing toggles. When set to true, the AuthKey must have permission to create database and collections. Defaults to false.
• AutoCreateFeature Enable auto creation of toggles as a json documents. When set to true, the AuthKey must have write permissions to the document collection. Defaults to false.

NOTE: The id property the json document representing the feature toggle must match the name of the class representing the feature toggle.

DateTime based feature toggles

The DocumentDbProvider supports feature toggles such as FeatureToggle.EnabledOnOrBeforeDateFeatureToggle and FeatureToggle.EnabledOnOrAfterDateFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable on a specific date and time:

public class ComingSoonFeature : EnabledOnOrAfterDateFeatureToggle
{
    public ComingSoonFeature()
    {
        this.ToggleValueProvider = new DocumentDbProvider();
    }
}

The json document to control the feature toggle looks like this:

{
    "id": "ComingSoonFeature",
    "ToggleTimestamp": "2018-05-24T20:21:00"    
}

Period based feature toggles

The DocumentDbProvider supports feature toggles such as FeatureToggle.EnabledBetweenDatesFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable during a specific period:

public class LimitedTimeFeature : EnabledBetweenDatesFeatureToggle
{
    public LimitedTimeFeature()
    {
        this.ToggleValueProvider = new DocumentDbProvider();
    }
}

The json document to control the feature toggle looks like this:

{
    "id": "LimitedTimeFeature",
    "Start": "2018-08-15T00:00:00",
    "End": "2018-08-20T23:59:59"    
}

FeatureToggle.Azure.TableStorage

FeatureToggle provider for storing feature toggles as table entities in Azure Table storage (part of Azure Storage Accounts). The nuget package can be found on nuget.org.

Getting started

1. Install FeatureToggle.Azure.TableStorage from nuget into your project.
2. Configure TableStorageProvider at application startup, such as in Global.asax or Startup.cs by specifying the connection string for the Azure Storage Account that will be used to store and retreive features toggles in Table storage. Global.asax example:

protected void Application_Start()
{
    // other startup configuration
    TableStorageProvider.Configure("[azurestorage_connectionstring]");
}

3. Add a class to your project representing the feature that needs to be controlled, e.g. PrintFeature and inherit from TableStorageToggle

public class PrintFeature : TableStorageToggle
{
}

4. Use the new feature toggle in your code to isolate features.

public ActionResult Index()
{
    ViewBag.EnablePrint = Is<PrintFeature>.Enabled;
    return View();
}

5. Add a table entity in Table storage, either using the Cloud Explorer in the Visual Studio or the standalone Azure Storage Explorer (ASE) or through the client API of Table storage in order to turn on/off the feature. The table entity must have the following properties:

• PartitionKey: Value must be the assembly name containing the feature toggle, unless overriden in configuration, see below.
• RowKey: Value must be the class name of the feature toggle.
• Enabled: true/false boolean value.

Provider Configuration

In order to control how the TableStorageProvider fetches feature toggles from Table Storage, the provider can be configured through an instance of TableStorageConfiguration passed to the overloaded static method TableStorageProvider.Configure(tableStorageconfig).

The following options can be controlled through the configuration instance:

• ConnectionString The connection string to the storage account for Azure Table Storage.
• TableName The table name where toggles are stored. Defaults to FeatureToggles.
• AutoCreateTable Enable auto creation of the table storing toggles. When set to true, the connection string SAS token must have permission to create tables. Defaults to false.
• AutoCreateFeature Enable auto creation of toggles as table entities. When set to true, the connection string SAS token must have write permissions to the table. Defaults to false.
• PartitionKeyResolver Provides the option to define the table partition key through a function. Defaults to the assembly name containing the feature toggle.

NOTE: The RowKey of the table entity representing the feature toggle must match the name of the class representing the feature toggle.

DateTime based feature toggles

The TableStorageProvider supports feature toggles such as FeatureToggle.EnabledOnOrBeforeDateFeatureToggle and FeatureToggle.EnabledOnOrAfterDateFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable on a specific date and time:

public class ComingSoonFeature : EnabledOnOrAfterDateFeatureToggle
{
    public ComingSoonFeature()
    {
        this.ToggleValueProvider = new TableStorageProvider();
    }
}

The table entity that controls the feature toggle must have a DateTime property called ToggleTimestamp.

Period based feature toggles

The TableStorageProvider supports feature toggles such as FeatureToggle.EnabledBetweenDatesFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable during a specific period:

public class LimitedTimeFeature : EnabledBetweenDatesFeatureToggle
{
    public LimitedTimeFeature()
    {
        this.ToggleValueProvider = new TableStorageProvider();
    }
}

The table entity that controls the feature toggle must have a DateTime property called Start and a DateTime property called End.

FeatureToggle.Azure.ServiceFabric

FeatureToggle provider for storing feature toggles in Service Fabric configuration packages (Settings.xml files). The nuget package can be found on nuget.org.

Getting started

1. Install FeatureToggle.Azure.ServiceFabric from nuget into your project.
2. Add a class to your project representing the feature that needs to be controlled, e.g. CoolNewFeatureToggle and inherit from ServiceFabricToggle

public class CoolNewFeatureToggle : ServiceFabricToggle
{
}

3. Use the new feature toggle in your code to isolate features.

public IActionResult Index()
{
    ViewData["Message"] = Is<CoolNewFeatureToggle>.Enabled ? "Cool Feature enabled" :-D" : "No cool feature for U :-["; 
    return View();
}

4. Add a configuration section and parameter to the Settings.xml file in PackageRoot\Config folder in order to turn on/off the feature. Like so:

<Section Name="Features">
    <Parameter Name="FeatureToggle.CoolNewFeatureToggle" Value="true" />
</Section>

Provider Configuration

If needed it is possible to control how and where the ServiceFabricConfigProvider fetches features toggles from SF configuration packages. The provider can be configured using the static method Configure which must be done when the Service Fabric service starts. The following parameters can be set:

• configPackageName The name of the Service Fabric configuration package. Defaults to Config.
• configSectionName The configuration section name in Settings.xml that hold feature toggles. Defaults to Features.
• usePrefix Controls whether features toggles must be prefixed with FeatureToggle. Defaults to true.

NOTE: The parameter name attribute in Settings.xml representing the feature toggle must match the name of the class representing the feature toggle, and unless disabled (see above) it must be prefixed with FeatureToggle.

DateTime based feature toggles

The ServiceFabricConfigProvider supports feature toggles such as FeatureToggle.EnabledOnOrBeforeDateFeatureToggle and FeatureToggle.EnabledOnOrAfterDateFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable on a specific date and time:

public class ComingSoonFeature : EnabledOnOrAfterDateFeatureToggle
{
    public ComingSoonFeature()
    {
        this.ToggleValueProvider = new ServiceFabricConfigProvider();
    }
}

The Settings.xml config file that controls the feature toggle looks like this:

<Section Name="Features">
    <Parameter Name="FeatureToggle.ComingSoonFeature" Value="24-May-2018 20:44:00" />
</Section>

Period based feature toggles

The ServiceFabricConfigProvider supports feature toggles such as FeatureToggle.EnabledBetweenDatesFeatureToggle, part of the FeatureToggle package, that must be installed seperately from the provider.

Example of a feature toggle that will enable during a specific period:

public class LimitedTimeFeature : EnabledBetweenDatesFeatureToggle
{
    public LimitedTimeFeature()
    {
        this.ToggleValueProvider = new ServiceFabricConfigProvider();
    }
}

The Settings.xml config file that controls the feature toggle looks like this:

<Section Name="Features">
    <Parameter Name="FeatureToggle.LimitedTimeFeature" Value="15-Aug-2018 00:00:00 | 20-Aug-2018 23:59:59" />
</Section>

Samples

The samples folder contains a single Samples.sln solution containing samples of the 3 FeatureToggle providers from the FeatureToggle.Azure packages. In order try these out locally, the following must be installed:

• Service Fabric SDK with local cluster setup which can be downloaded through Web Platform Installer
• Cosmos DB Emulator
• Azure Storage Emulator

ASP.NET Web App sample

The project WebApplication is a standard ASP.NET Web App (.NET Framework) showing how to configure and use FeatureToggle.Azure.DocumentDB and FeatureToggle.Azure.TableStorage. The configuration of the providers is located in the Global.asax.csfile. Both providers are configured for using local emulators with auto creation of storage and toggles.

Feature toggles are found in the FeatureToggles folder and are used in the HomeController.

• The FrontPageUIFeature is a boolean FeatureToggle, and toggles a message on the Front page of the web app and is stored in Table Storage (emulator).
• The AboutPageFeature is a boolean FeatureToggle, and toggles a message on the About page of the web app and is stored in DocumentDb (emulator).
• The ComingSoonFeature is a DateTime FeatureToggle, and toggles a message on the the Front page of the web app and is stored in DocumentDb (emulator).
• The RetiringSoonFeature is a DateTime FeatureToggle, and toggles a message on the Contact page of the web app and is stored in Table Storage (emulator).
• The LimitedTimeFeature is a Period FeatureToggle, and toggles a message on the Front page of the web app and is stored in Table Storage (emulator).

In order to change the toggle values after creation, you can use the Cloud Explorer in Visual Studio or the Azure Storage Explorer.

ASP.NET Core sample running in Service Fabric

The project SfWebAppCore is a ASP.NET Core Web App packaged as a Service Fabric application (the ServiceFabricApplication project). This sample shows how to configure and use FeatureToggle.Azure.ServiceFabric. The optional configuration of the provider is located in the Startup.cs file. The configuration package is located in PackageRoot/Config/Settings.xml file of the SfWebAppCore project.

Feature toggles are found in the FeatureToggles folder and are used in the HomeController.

• The CoolNewFeatureToggle is a boolean FeatureToggle, and toggles a message on the About page of the web app.
• The ComingSoonFeature is a DateTime FeatureToggle, and toggles a message on the Front page of the web app.
• The RetiringSoonFeature is a DateTime FeatureToggle, and toggles a message on the Contact page of the web app.
• The LimitedTimeFeature is a Period FeatureToggle, and toggles a message on the Front page of the web app.

In order to toggle the value, the configuration package must be packaged and deployed to the local cluster.