PrimusSaaS.FeatureFlags 1.0.0

.NET 6.0 This package targets .NET 6.0. The package is compatible with this framework or higher.
There is a newer version of this package available.
See the version list below for details. 
dotnet add package PrimusSaaS.FeatureFlags --version 1.0.0
                    


                    

                
NuGet\Install-Package PrimusSaaS.FeatureFlags -Version 1.0.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="PrimusSaaS.FeatureFlags" Version="1.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="PrimusSaaS.FeatureFlags" Version="1.0.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="PrimusSaaS.FeatureFlags" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add PrimusSaaS.FeatureFlags --version 1.0.0
                    


                    

                
#r "nuget: PrimusSaaS.FeatureFlags, 1.0.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package PrimusSaaS.FeatureFlags@1.0.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=PrimusSaaS.FeatureFlags&version=1.0.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=PrimusSaaS.FeatureFlags&version=1.0.0
                    


                            Install as a Cake Tool

PrimusSaaS Feature Flags

Lightweight feature flag management for .NET applications. Supports in-memory, file-based, and Azure App Configuration providers.

NuGet Version License: MIT

Features

  • Multiple Providers: In-memory, JSON file, or Azure App Configuration
  • Percentage Rollouts: Gradual feature rollouts with consistent hashing
  • User Targeting: Enable features for specific users or groups
  • Time-Based Activation: Schedule feature availability windows
  • Hot Reload: JSON file provider supports live updates
  • ASP.NET Core Integration: DI extensions and middleware support

Installation

dotnet add package PrimusSaaS.FeatureFlags

Quick Start

1. Register Services

// In Program.cs
builder.Services.AddPrimusFeatureFlags(options =>
{
    options.Provider = FeatureFlagProvider.InMemory;
    options.Flags["NewDashboard"] = new FeatureFlagDefinition
    {
        Enabled = true,
        Description = "Enable the new dashboard UI"
    };
    options.Flags["BetaFeature"] = new FeatureFlagDefinition
    {
        Enabled = false,
        RolloutPercentage = 25, // 25% of users
        EnabledForGroups = ["beta-testers"]
    };
});

2. Use in Controllers/Services

public class DashboardController : ControllerBase
{
    private readonly IFeatureFlagService _featureFlags;

    public DashboardController(IFeatureFlagService featureFlags)
    {
        _featureFlags = featureFlags;
    }

    [HttpGet]
    public IActionResult GetDashboard()
    {
        if (_featureFlags.IsEnabled("NewDashboard", User))
        {
            return Ok(new { version = "v2", features = GetNewFeatures() });
        }
        
        return Ok(new { version = "v1", features = GetLegacyFeatures() });
    }
}

Configuration Options

In-Memory Provider (Default)

builder.Services.AddPrimusFeatureFlags(options =>
{
    options.Provider = FeatureFlagProvider.InMemory;
    options.DefaultValue = false;
    options.Flags["MyFeature"] = new FeatureFlagDefinition
    {
        Enabled = true,
        Description = "My awesome feature",
        RolloutPercentage = 50,
        EnabledForUsers = ["user1@example.com", "user2@example.com"],
        EnabledForGroups = ["admins", "beta-testers"],
        StartTime = DateTimeOffset.UtcNow,
        EndTime = DateTimeOffset.UtcNow.AddDays(30)
    };
});

JSON File Provider

builder.Services.AddPrimusFeatureFlags(options =>
{
    options.Provider = FeatureFlagProvider.JsonFile;
    options.JsonFilePath = "featureflags.json";
});

featureflags.json:

{
  "NewDashboard": {
    "Enabled": true,
    "Description": "New dashboard UI",
    "RolloutPercentage": 100
  },
  "BetaFeature": {
    "Enabled": false,
    "RolloutPercentage": 25,
    "EnabledForGroups": ["beta-testers"]
  }
}

Configuration Binding

builder.Services.AddPrimusFeatureFlags(options =>
{
    builder.Configuration.GetSection("PrimusFeatureFlags").Bind(options);
});

appsettings.json:

{
  "PrimusFeatureFlags": {
    "Provider": "InMemory",
    "DefaultValue": false,
    "CacheDurationSeconds": 30,
    "Flags": {
      "NewDashboard": {
        "Enabled": true,
        "RolloutPercentage": 50
      }
    },
    "Logging": {
      "LogEvaluations": true,
      "IncludeUserContext": false
    }
  }
}

Feature Flag Evaluation

Simple Check

if (_featureFlags.IsEnabled("MyFeature"))
{
    // Feature is enabled globally
}

User-Specific Check

// With user ID
if (_featureFlags.IsEnabled("MyFeature", "user123"))
{
    // Feature is enabled for this user
}

// With ClaimsPrincipal (from HttpContext.User)
if (_featureFlags.IsEnabled("MyFeature", User))
{
    // Feature is enabled based on user claims
}

Custom Context

var context = new FeatureFlagContext
{
    UserId = "user123",
    Email = "user@example.com",
    Groups = ["admins", "beta-testers"],
    Attributes = { ["region"] = "us-west" }
};

if (_featureFlags.IsEnabled("MyFeature", context))
{
    // Feature is enabled for this context
}

Async Evaluation

var isEnabled = await _featureFlags.IsEnabledAsync("MyFeature", User);

Targeting Rules

Feature flags are evaluated in the following order:

  1. Time-Based: Check if current time is within StartTime/EndTime window
  2. User Targeting: Check if user ID is in EnabledForUsers list
  3. Group Targeting: Check if user belongs to any EnabledForGroups
  4. Percentage Rollout: Use consistent hashing to determine if user is in rollout
  5. Global Enabled: Fall back to the Enabled flag

API Reference

IFeatureFlagService

Method Description
IsEnabled(featureName) Check if feature is globally enabled
IsEnabled(featureName, userId) Check if feature is enabled for user ID
IsEnabled(featureName, ClaimsPrincipal) Check if feature is enabled for claims
IsEnabled(featureName, context) Check with custom context
GetAllFlagsAsync() Get all feature flags and states
GetFlagDefinitionAsync(featureName) Get feature flag definition
RefreshAsync() Force refresh from provider

FeatureFlagDefinition

Property Type Description
Enabled bool Global enabled state
Description string? Human-readable description
RolloutPercentage int? Percentage of users (0-100)
EnabledForUsers List<string> User IDs always enabled
EnabledForGroups List<string> Group names always enabled
StartTime DateTimeOffset? Activation start (UTC)
EndTime DateTimeOffset? Activation end (UTC)
Metadata Dictionary<string, string> Custom key-value pairs

Best Practices

  1. Use meaningful flag names: NewCheckoutFlow not feature1
  2. Set descriptions: Document what each flag controls
  3. Clean up old flags: Remove flags after full rollout
  4. Use percentage rollouts: Gradual rollouts reduce risk
  5. Monitor evaluations: Enable logging to track usage
  • PrimusSaaS.Identity.Validator - Multi-issuer JWT validation
  • PrimusSaaS.Logging - Structured logging with PII masking
  • PrimusSaaS.Notifications - Email/SMS notifications

License

MIT License - see LICENSE for details.

Product Compatible and additional computed target framework versions.
.NET net6.0 is compatible.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 is compatible.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 was computed.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
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NuGet packages

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Version Downloads Last Updated
2.0.0 85 1/12/2026
1.0.0 204 12/3/2025

v1.0.0:
- Initial release with in-memory and file-based feature flag providers.
- Percentage rollout support with consistent hashing.
- User targeting by claims (userId, email, groups).
- Time-based activation windows.
- ASP.NET Core DI integration via AddPrimusFeatureFlags().
- Real-time flag evaluation with IFeatureFlagService.