Isici - successor of Switcheroo

Isici is Feature in Zulu

A lightweight framework for feature toggling to enable trunk based development. Isici aims for simplicity, with a clean syntax and a minimal feature set while not compromising on extensibility and testability.

Isici is the successor of the Switcheroo package developed by Riaan Hanekom. Isici has been split into separate packages for modular development and also now supports .net 4.5.x and up via netstandard 2.0.

Getting Isici

Isici can be installed via Nuget.

> Install-Package Isici.Core 

> dotnet add package Isici.Core

<PackageReference Include="Isici.Core" Version="1.1.1" />

> paket add Isici.Core

License

Isici is licensed under the MIT license.

Quick Start

Installation

Nuget packages:

• Isici.Core: core package needed to implement the feature flags
• Isici.Core.Abstractions: abstractions package with implementation in Isici.Core

Add configuration

Currently there are 2 IconfigurationProviders supported:

• Isici.Configuration.SystemConfiguration: uses the System.Configuration.ConfigurationManager to load configuration from *.config files with support for custom sections. This is the original implementtion as was in Switcheroo.

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

• Isici.Configuration.JsonFileConfiguration: uses a json file to load configuration from. This is the original implementation by myself which was a contribution for switcherooo.

[
  {
    "name": "testDateRange",
    "enabled": true,
    "from": "1 November 2012",
    "until": "2 November 2012"
  }
]

Custom configuration sources You can implement your own configuration source by implementing the IConfigurationReader in the Isici.Core.Abstractions package. Feel free to contribute other sources.

Toggle types

Boolean (true/false)

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

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

System.configuration

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

Json file

[
  {
    "name": "Feature1",
    "enabled": true
  }
]

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));

System.configuration

<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>

Json file

[
  {
    "name": "Feature2",
    "enabled": true,
    "from": "1 November 2012",
    "until": "2 November 2012"
  }
]

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"));

System.configuration

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

Json file

[
  {
    "name": "establishedFeature",
    "established": true
  }
]

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);

System.configuration

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

Json file

[
  {
    "name": "mainFeature",
    "enabled": true,
    "dependencies": [
      "subFeature1",
      "subFeature2"
    ]
  },
  {
    "name": "subFeature1",
    "enabled": true
  },
  {
    "name": "subFeature2",
    "enabled": true
  }
]

Other features

Code-friendly initialization

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

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