I’ve been reading this article: https://docs.microsoft.com/en-us/azure/azure-app-configuration/use-feature-flags-dotnet-core?tabs=core5x

Maybe it’s there and I’ve missed it or I haven’t come across it yet But I’m wondering how to move the config for my toggles outside of the appsettings file into another file just for feature flags.

A reference to an article or tutorial is what I’m looking for. Thanks

EDIT 1

This is what my Startup.cs has:

public void ConfigureServices(IServiceCollection services)
        {
            var appSettings = new AppSettings
            {
                ConnectionString = Configuration["AppSettings:ConnectionString"],
                Environment = Configuration["AppSettings:Environment"],
                EncryptionPassword = Configuration["AppSettings:EncryptionPassword"]
                Version = Assembly.GetExecutingAssembly().GetName().Version.ToString())
            };

            services.AddFeatureManagement(Configuration.GetSection("FeatureManagement")).AddFeatureFilter<WidgetsFeaturesFilter>();

EDIT 2

I moved the feature management section from appsettings.json into a new file in the same location / folder as appsettings.json called "FeatureFlags.json". But when I build, and try to call a method that has a feature toggle check, I see this warning:

Warn: Microsoft.FeatureManagement.FeatureManager[0] The feature declaration for the feature 'WidgetsApi' was not found. Microsoft.FeatureManagement.FeatureManager: Warning: The feature declaration for the feature 'WidgetsApi' was not found.

Here's all the code:

FeatureFlags.json

{
  "FeatureManagement": {
    "AddWidgets": {
      "EnabledFor": [
        {
          "Name": "Widgets2Features"
        }
      ]
    },
    "WidgetsApi": {
      "EnabledFor": [
        {
          "Name": "Widgets2Features"
        }
      ]
    }
  }
}

WidgetsFeaturesFilter.cs

using System.Linq;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.FeatureManagement;

namespace My.Server.Features
{
    [FilterAlias("Widgets2Features")]
    public class WidgetsFeaturesFilter : IFeatureFilter
    {
        private readonly IServiceScopeFactory scopeFactory;

        public WidgetsFeaturesFilter(IServiceScopeFactory scopeFactory)
        {
            this.scopeFactory = scopeFactory;
        }

        public Task<bool> EvaluateAsync(FeatureFilterEvaluationContext context)
        {
            using var scope = scopeFactory.CreateScope();
            var featureRepo = scope.ServiceProvider.GetService<IGenericRepository<WidgetFeatures>>();
            var feature = featureRepo.Retrieve(filter: "[Name] = @FeatureName", filterParameters: new { context.FeatureName }).FirstOrDefault();
            return Task.FromResult(feature != null && feature.Enabled);
        }
    }
}

Program.cs

using System;
using System.Diagnostics;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Serilog;

namespace My.Server
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Logging.Serilog.Initialize();
            try
            {
                Log.Information($"Starting web host on process id { Process.GetCurrentProcess().Id }");

                CreateHostBuilder(args).Build().Run();
            }
            catch (Exception ex)
            {
                Log.Fatal(ex, "Host terminated unexpectedly");
            }
            finally{
                Log.CloseAndFlush();
            }
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((context, builder) =>
                {
                    builder.AddJsonFile("FeatureFlags.json");
                })
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

CodePudding user response：

You can create a JSON file with feature flags and include it in the configuration system. Here is the code.

If you're using ASP.NET Core 6.0 - Modify the Program.cs

var builder = WebApplication.CreateBuilder(args);
builder.Configuration.AddJsonFile("FeatureFlags.json");

And if you're using ASP.NET Core 5.0 - Modify the Program.cs

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((context, builder) =>
        {
            builder.AddJsonFile("FeatureFlags.json");
        })
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });