FeatureFlags.Lite.Core 1.1.0

FeatureFlags.Lite

Overview

FeatureFlags.Lite is a lightweight, easy-to-use feature flag library for .NET applications. It supports in-memory and configuration-based feature flags, with optional ASP.NET Core middleware for attribute-based endpoint gating.

Key Features

• Toggle features on/off via configuration or in-memory provider.
• Rollout support for percentage-based feature flags.
• Environment-specific overrides.
• Role-based access control via AllowedRoles.
• ASP.NET Core middleware for [FeatureGate("FeatureName")] attributes.

Installation

git clone https://github.com/FarukA1/FeatureFlags.Lite.git

Quick Start

Add services

using FeatureFlags.Lite.Core.Extensions;
using FeatureFlags.Lite.AspNet.Extensions;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddFeatureFlags();

// Optional: add configuration provider
builder.Services.AddSingleton<ConfigurationFeatureFlagProvider>(sp =>
    new ConfigurationFeatureFlagProvider(builder.Configuration)
);
builder.Services.AddSingleton<IFeatureFlagProvider>(sp =>
    sp.GetRequiredService<ConfigurationFeatureFlagProvider>()
);

var app = builder.Build();

Use middleware in ASP.NET Core

app.UseFeatureFlags();

Protect endpoints with [FeatureGate]

using FeatureFlags.Lite.AspNet.Attributes;
using Microsoft.AspNetCore.Mvc;

[ApiController]
[Route("[controller]")]
public class DemoController : ControllerBase
{
    [HttpGet("feature-a")]
    [FeatureGate("FeatureA")]
    public IActionResult FeatureA() => Ok("FeatureA is enabled!");

    [HttpGet("public")]
    public IActionResult Public() => Ok("Always accessible.");
}

Configure feature flags via appsettings.json

  "FeatureFlags": {
    "FeatureA": {
      "Enabled": true
    },
    "FeatureB": {
      "Enabled": false
    },
    "FeatureC": {
      "Enabled": true,
      "RolloutPercentage": 50
    },
    "FeatureD": {
      "Enabled": true,
      "AllowedRoles": [ "Admin", "Manager" ]
    },
    "FeatureE": {
      "Enabled": true,
      "EnvironmentOverrides": {
        "Development": true,
        "Production": false
      }
    }
  }
}

Using in-memory feature flags (optional)

var inMemoryProvider = new InMemoryFeatureFlagProvider(new[]
{
    new FeatureFlag { Name = "FeatureA", Enabled = true },
    new FeatureFlag { Name = "FeatureB", Enabled = false }
});

var service = new FeatureFlagService(inMemoryProvider, new DefaultFeatureEvaluator());
service.IsEnabled("FeatureA");

Contribution

Contributions is welcomed. If you find a bug or have an enhancement in mind, feel free to open an issue or submit a pull request.