muench-develops.FeatureToggler 1.0.3

muench-develops.FeatureToggler

muench-develops.FeatureToggler is a lightweight and extensible library for managing feature flags in .NET applications. It allows you to dynamically enable or disable features using multiple providers.

Features

• Multiple Providers: In-Memory, JSON, Environment Variables.
• ASP.NET Core Integration: Middleware for feature-based request handling.
• Extensible: Easily add custom providers.
• Thread-Safe: Safe for concurrent updates and queries.

Installation

Install via NuGet:

dotnet add package muench-develops.FeatureToggler

Quick Start

1. Register Feature Flags

In-Memory Provider

For quick development and testing:

builder.Services.AddFeatureFlags(
    new InMemoryFeatureFlagProvider(
        new[]
        {
            new FeatureFlag("EnableNewUI", true, "Enables the new UI"),
            new FeatureFlag("BetaFeature", false, "Beta feature toggle")
        })
);

JSON Provider

To manage feature flags via a JSON file, use JsonFeatureFlagProvider:

1. Create a JSON file, e.g., featureflags.json:

[
    { "Key": "EnableNewUI", "IsEnabled": true, "Description": "Enables the new UI" },
    { "Key": "BetaFeature", "IsEnabled": false, "Description": "Beta feature toggle" }
]

2. Register the provider in Program.cs:

builder.Services.AddFeatureFlags(
    new JsonFeatureFlagProvider("path/to/featureflags.json", new FileReader())
);

Environment Variable Provider

Use environment variables to control feature flags dynamically:

1. Set environment variables:

$env:ENABLE_NEW_UI = "true"
$env:BETA_FEATURE = "false"

2. Register the provider in Program.cs:

builder.Services.AddFeatureFlags(
    new EnvironmentVariableFeatureFlagProvider(new Dictionary<string, string>
    {
        { "EnableNewUI", "ENABLE_NEW_UI" },
        { "BetaFeature", "BETA_FEATURE" }
    })
);

Configuration Provider

The ConfigurationFeatureFlagProvider enables you to manage feature toggles directly from the .NET IConfiguration system, which can include sources like appsettings.json, environment variables, or other configuration providers.

{
  "FeatureToggles": {
    "EnableNewUI": {
      "IsEnabled": true,
      "Description": "Enables the new UI"
    },
    "BetaFeature": {
      "IsEnabled": false,
      "Description": "This is a beta feature toggle"
    }
  }
}

using FeatureToggler.Providers;

var builder = WebApplication.CreateBuilder(args);

// Register Feature Flags with the Configuration Provider
builder.Services.AddFeatureFlags(
    new ConfigurationFeatureFlagProvider(builder.Configuration)
);

var app = builder.Build();

2a. Use Middleware

Execute actions based on feature flag states:

app.UseFeatureFlag("EnableNewUI",
    onEnabled: () => Console.WriteLine("New UI is enabled!"),
    onDisabled: () => Console.WriteLine("New UI is disabled!"));

2b. Use Minimal API

app.MapGet("/", (FeatureFlagManager manaer) => manager.IsEnabled("EnableNewUI")
        ? Results.Ok("Welcome to the new UI!")
        : Results.Ok("Welcome to the old UI!"));

3. Query Flags

Check or update feature flags dynamically:

var manager = app.Services.GetRequiredService<FeatureFlagManager>();

if (manager.IsEnabled("EnableNewUI"))
{
    Console.WriteLine("New UI is enabled!");
}

License

This project is licensed under the Apache License. See the LICENSE file for details.