Switcheroo

A lightweight framework for feature toggling to enable trunk based development.

Switcheroo aims for simplicity, with a clean syntax and a minimal feature set while not compromising on extensibility and testability.

Getting Switcheroo

Switcheroo can be installed via Nuget.

> Install-Package Switcheroo 

License

Switcheroo is licensed under the MIT license.

Quick Start

Installation

Nuget packages can be found here.

Add configuration

<configuration>
  <configSections>
    <section name="features" type="Switcheroo.Configuration.FeatureToggleConfiguration, Switcheroo"/>
  </configSections>
  <features>
    <toggles>
      <add name="Log.InColor" enabled="true"/>
    </toggles>
  </features>
</configuration>

Initializing the library

Features.Initialize(x => x.FromApplicationConfig());

Checking feature status

if (Features.IsEnabled("Log.InColor"))
{
    // Implement feature
}

Toggle types

Boolean (true/false)

Feature toggles based on a static binary value - either on or off.

features.Add(new BooleanToggle("Feature1", true));

<features>
    <toggles>
      <add name="BooleanToggle.Enabled" enabled="true"/>
      <add name="BooleanToggle.Disabled" enabled="false"/>
    </toggles>
 </features>

Date Range (true/false, within date range)

Date Range feature toggles are evaluated on both the binary enabled value and the current date.

features.Add(new DateRangeToggle("Feature2", true, DateTime.Now.AddDays(5), null));

<features>
    <toggles>
      <add name="Date.Enabled.InRange" enabled="true" from="1 January 2010" until="31 December 2050"/>
      <add name="Date.Enabled.Expired" enabled="true" until="31 December 2010"/>
      <add name="Date.Enabled.Future"  enabled="true" from="1 January 2050"/>
      <add name="Date.Disabled" enabled="false"/>
    </toggles>
 </features>

From and until dates can be any valid date format parseable by DateTime.Parse.

Established features

Marking a feature toggle as established makes the feature toggle throw a FeatureEstablishedException exception to make sure that it is not queried any more.

features.Add(new EstablishedFeatureToggle("establishedFeature"));

<features>
    <toggles>
      <add name="EstablishedFeature" established="true"/>
    </toggles>
 </features>

Dependencies

Features can depend on other features. For instance, it is sometimes convenient to have a "main" feature, and then sub-features that depend on it. Dependencies can be specified in configuration as a comma delimited list.

var mainFeature = new BooleanToggle("mainFeature", true);
var subFeature1 = new BooleanToggle("subFeature1", true);
var subFeature2 = new BooleanToggle("subFeature2", true);

var dependency1 = new DependencyToggle(subFeature1, mainFeature);
var dependency2 = new DependencyToggle(subFeature2, mainFeature);
features.Add(dependency1);
features.Add(dependency2);

<features>
    <toggles>
        <add name="SubFeature1" enabled="true" dependencies="MainFeature"/>
        <add name="SubFeature2" enabled="true" dependencies="MainFeature"/>
        <add name="MainFeature" enabled="true" />
    </toggles>
 </features>

Other features

Code-friendly initialization

IFeatureConfiguration features = new FeatureConfiguration
    {
        new BooleanToggle("Feature1", true),
        new DateRangeToggle(
            "Feature2",
            true,
            DateTime.Now.AddDays(-2),
            DateTime.Now.AddDays(3))
    };

IOC friendly through IFeatureConfiguration instances, or the static Feature.Instance backing instance

For<IFeatureConfiguration>().Use(Features.Instance);

Feature toggle diagnostics : IFeatureConfiguration.WhatDoIHave

Console.WriteLine(features.WhatDoIHave());

Name          Feature1
IsEnabled     True


Name          Feature2
IsEnabled     True
From          11/16/2012 3:32:23 PM
Until         11/21/2012 3:32:23 PM

Loading from custom configuration resources : build on top of IConfigurationReader

Version History

0.3.4753.37554

• Removed MutableToggle
• Added the ability to "freeze" a toggle configuration.
• Validation of toggle state (including cycles in dependencies) now occur on addition to the feature configuration container.

0.3.4749.36197

• Mechanism for detecting dependency cycles. This feature is only active when configuring dependencies via application configuration.
• Fixed bug where a DependencyToggle depending on another DependencyToggle might cause duplicate toggles to be added to the feature set.

v0.3.4748.37146

• Configuration mechanism for DependencyToggle

v0.2.4730.37739

• Added DependencyToggle.
• Changed from a Dictionary to a ConcurrentDictionary.

v0.2.4705.37094

• Added Established features.

v0.1.4705.28808

• Added DateRange toggle.
• Quite a bit of internal refactoring.

v0.1.4704.41742

• Initial version : simple toggles.