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.