NOW FeatureFlag Extensions is a set of extensions to support feature switching

What if you want to alter, or re-write a (part) of a service, factory, or any other class, that is registered in your application via (Microsoft) Dependency Injection. But, you want to use feature switches/toggles, without having to alter existing code in the class, and without having to restart the running application in order to test the experimental/new code? This question produced this (experimental) project and it's additional libraries.

NOW.FeatureFlagExtensions/src/FeatureTestApplication/Program.cs

Lines 115 to 128 in dffd71a

	// Register feature management and filters using Microsoft.FeatureManagement.
	builder.Services.AddFeatureManagement()
	.AddFeatureFlagExtensionsFeatureFilters();
	builder.Services.AddFeatureFlagFeatureManagementManager();
	builder.Services.AddScoped<DefaultInjectionTests.ScopedFeature.ITestServiceScoped, DefaultInjectionTests.ScopedFeature.TestServiceOneScoped>(
	new FeatureFlagWrapper<DefaultInjectionTests.ScopedFeature.ITestServiceScoped>(
	typeof(DefaultInjectionTests.ScopedFeature.TestServiceTwoScoped),
	DefaultInjectionFlags.TestDefaultServiceScopedTwo),
	new FeatureFlagWrapper<DefaultInjectionTests.ScopedFeature.ITestServiceScoped>(
	typeof(DefaultInjectionTests.ScopedFeature.TestServiceThreeScoped),
	DefaultInjectionFlags.TestDefaultServiceScopedThree)
	);

Build Status

Branch	Status
master

NuGet Packages

Package Name	.NET 7
Dependency Injection
Main
FeatureManagement	Preview
Interceptors	Preview
Core
DependencyInjection	Preview
Managers	Preview
Models	Preview
Microsoft FeatureManagement
FeatureManagement	Preview
FeatureManagement.Swagger	Preview

Getting started

Clone the repository and run the included FeatureTestApplication, the default start-page will be the swagger documentation page, where you can play around with the registered test-features in combination with Api Versioning.

Additionally, you can visit /allservices, to display all service registrations. This endpoint uses the package Ardalis.ListStartupServices.

Features

Dependency Injection

A set of packages to enable "hot-reload" feature switching via Dependency Injection and some other, additional, extensions.

• NOW.FeatureFlagExtensions.DependencyInjection.FeatureManagement
  Enables "hot-reload" feature switching via Dependency Injection. This specific version depends on Microsoft FeatureManagement. read more...

  • Depends on: NOW.FeatureFlagExtensions.DependencyInjection
    Uses standard Dependency Injection features to enable switching, currently supports AddScoped and AddTransient extensions (no Singleton at this point). read more...
    • Depends on:
      • NOW.FeatureFlagExtensions.DependencyInjection.Managers
        Contains the abstract class FeatureFlagManager, if you want to enable switching via a feature switching/toggle library of your choice. Inherit this class and make it work! read more...
      • NOW.FeatureFlagExtensions.DependencyInjection.Models
        Contains the models used by the core libraries. read more...

• NOW.FeatureFlagExtensions.DependencyInjection.Interceptors
  An alternative/addition for the NOW.FeatureFlagExtensions.DependencyInjection extensions. You can use this one, the other one, or use them both depending on your use case. This package will add the extensions AddInterceptedScoped, AddInterceptedSingleton and AddInterceptedTransient. The extensions depend on the Castle.Core interceptors to do the heavy lifting. read more...

  • Depends on:
    • NOW.FeatureFlagExtensions.DependencyInjection.Managers
      Contains the abstract class FeatureFlagManager, if you want to enable switching via a feature switching/toggle library of your choice. Inherit this class and make it work! read more...
    • NOW.FeatureFlagExtensions.DependencyInjection.Models
      Contains the models used by the core libraries. read more...

Benchmarks

Executed using v1.1.0-preview (.net 6).

Vanilla Feature Flag Usage

NOW.FeatureFlagExtensions/src/Benchmarks/VanillaInjection/BenchmarkDotNet.Artifacts/results/NOW.FeatureFlagExtensions.Benchmarks.VanillaInjection.Benchmarks-report-github.md

Lines 11 to 15 in 2ac0c7d

	| Method | Mean | Error | StdDev | Rank | Gen 0 | Allocated |
	|------------------------ |---------:|--------:|--------:|-----:|-------:|----------:|
	| GetTestServiceScoped | 494.7 ns | 7.72 ns | 6.84 ns | 1 | 0.1001 | 840 B |
	| GetTestServiceSingleton | 505.8 ns | 5.34 ns | 4.46 ns | 2 | 0.1001 | 840 B |
	| GetTestServiceTransient | 507.0 ns | 1.96 ns | 1.84 ns | 2 | 0.1030 | 864 B |

FeatureFlagExtensions (Default) Usage

NOW.FeatureFlagExtensions/src/Benchmarks/DefaultInjection/BenchmarkDotNet.Artifacts/results/NOW.FeatureFlagExtensions.Benchmarks.DefaultInjection.Benchmarks-report-github.md

Lines 11 to 14 in 2ac0c7d

	| Method | Mean | Error | StdDev | Rank | Gen 0 | Allocated |
	|------------------------ |----------:|---------:|---------:|-----:|-------:|----------:|
	| GetTestServiceScoped | 27.81 ns | 0.258 ns | 0.241 ns | 1 | - | - |
	| GetTestServiceTransient | 627.39 ns | 7.377 ns | 6.160 ns | 2 | 0.1059 | 888 B |

FeatureFlagExtensions Interceptors Usage

NOW.FeatureFlagExtensions/src/Benchmarks/InterceptorInjection/BenchmarkDotNet.Artifacts/results/NOW.FeatureFlagExtensions.Benchmarks.InterceptorInjection.Benchmarks-report-github.md

Lines 11 to 15 in 2ac0c7d

	| Method | Mean | Error | StdDev | Rank | Gen0 | Allocated |
	|------------------------ |------------:|----------:|----------:|-----:|-------:|----------:|
	| GetTestServiceSingleton | 24.94 ns | 0.129 ns | 0.121 ns | 1 | - | - |
	| GetTestServiceScoped | 27.80 ns | 0.220 ns | 0.195 ns | 2 | - | - |
	| GetTestServiceTransient | 1,790.26 ns | 24.408 ns | 19.056 ns | 3 | 0.2613 | 2192 B |

Microsoft FeatureManagement

A set of extensions and additional filters, that build on the out-of-the-box Microsoft FeatureManagement configuration.

• NOW.FeatureFlagExtensions.FeatureManagement
  Add additional configurable filters like the AggregateFeatureFilter, ClaimsFeatureFilter, EnvironementsFeatureFilter and RequestHeadersFeatureFilter. read more...

• NOW.FeatureFlagExtensions.FeatureManagement.Swagger
  Adds a FeatureFilterHeaderParameter for swagger, to enable easy feature switching via dropdown(s), that is (are) populated with all available feature switches. read more...

Community

This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behavior in our community. For more information, see the Code of Conduct.