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Feature Flags Integration Guide

Choose your provider below and follow the 5-step integration guide.

Provider: InMemory (Standard)​

Best for development and simple applications where flags are managed in standard configuration.

Step 1: Install the package​

dotnet add package PrimusSaaS.FeatureFlags

Step 2: Configure Program.cs​

using PrimusSaaS.FeatureFlags;

var builder = WebApplication.CreateBuilder(args);

// Register Feature Flags service
builder.Services.AddPrimusFeatureFlags(options => 
    builder.Configuration.GetSection("PrimusFeatureFlags").Bind(options));

var app = builder.Build();

Step 3: Configure appsettings.json​

Define your flags directly in the Flags object.

{
  "PrimusFeatureFlags": {
    "Provider": "InMemory",
    "Flags": {
      "NewDashboard": {
        "Enabled": true,
        "RolloutPercentage": 50
      },
      "BetaFeature": {
        "Enabled": true,
        "EnabledForUsers": ["user-123", "user-456"]
      }
    }
  }
}

Step 4: Configure endpoint​

Inject IFeatureFlagService into your controller.

using Microsoft.AspNetCore.Mvc;
using PrimusSaaS.FeatureFlags;

[ApiController]
[Route("api/[controller]")]
public class FeatureController : ControllerBase
{
    private readonly IFeatureFlagService _flags;

    public FeatureController(IFeatureFlagService flags)
    {
        _flags = flags;
    }

    [HttpGet("check/{feature}")]
    public IActionResult CheckFeature(string feature)
    {
        var isEnabled = _flags.IsEnabled(feature);
        return Ok(new { feature, enabled = isEnabled });
    }
}

Step 5: Test the endpoint​

curl http://localhost:5000/api/feature/check/NewDashboard

Provider: JsonFile​

Best for scenarios requiring hot-reloading of flags without restarting the application.

Step 1: Install the package​

dotnet add package PrimusSaaS.FeatureFlags

Step 2: Configure Program.cs​

using PrimusSaaS.FeatureFlags;

var builder = WebApplication.CreateBuilder(args);

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

Step 3: Configure appsettings.json​

Point the provider to an external JSON file.

{
  "PrimusFeatureFlags": {
    "Provider": "JsonFile",
    "JsonFilePath": "flags.json"
  }
}

Note: You must also create a flags.json file in your project root and ensure it is copied to the output directory.

flags.json:

{
  "NewDashboard": {
    "Enabled": true,
    "Description": "New UI Version"
  }
}

Step 4: Configure endpoint​

Implementation is identical to the InMemory provider.

// Inject IFeatureFlagService as shown above

Step 5: Test the endpoint​

curl http://localhost:5000/api/feature/check/NewDashboard

Provider: Azure App Configuration​

Best for distributed systems requiring centralized management. This provider is not available in the core package yet.

Step 1: Install the package​

dotnet add package PrimusSaaS.FeatureFlags

The Azure App Configuration provider requires a separate provider package. If it is not published in your feed yet, you cannot use this provider.

Step 2: Configure Program.cs​

using PrimusSaaS.FeatureFlags;

var builder = WebApplication.CreateBuilder(args);

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

Step 3: Configure appsettings.json​

Set the provider to AzureAppConfiguration and provide the connection string.

{
  "PrimusFeatureFlags": {
    "Provider": "AzureAppConfiguration",
    "AzureAppConfigConnectionString": "Endpoint=https://your-config.azconfig.io;Id=...;Secret=...",
    "CacheDurationSeconds": 60
  }
}

Step 4: Configure endpoint​

Implementation is identical to other providers.

// Inject IFeatureFlagService as shown above

Step 5: Test the endpoint​

curl http://localhost:5000/api/feature/check/NewDashboard