feat: Feature Provider Enhancement - #321

[arttonoyan]

This update focuses on enhancing the feature provider integration and testing framework, incorporating improvements to flexibility, usability, and testing capabilities.
This update addresses GitHub Issue #321 in the OpenFeature .NET SDK repository.

---

Key Enhancements

1. Dependency Injection (DI) Enhancements:

   • Improved lifecycle management for better resource handling.
   • Streamlined registration for feature providers, reducing configuration complexity.
   • Introduced the AddProvider extension method to simplify and adapt feature provider integration during service setup.

2. Simplified Codebase:

   • Removed FeatureProviderFactory logic, eliminating unnecessary complexity and improving usability.

3. Improved InMemoryProvider:

   • Enhanced the registration process for the InMemoryProvider, enabling smoother and more intuitive usage.

4. Testing Improvements:

   • Established a dedicated integration test project for comprehensive validation.
   • Improved overall test coverage, ensuring the reliability and robustness of the framework.

---

Example: Service Registration and Usage

Service Registration

builder.Services.TryAddSingleton<IFeatureFlagConfigurationService, FlagConfigurationService>();

builder.Services.AddHttpContextAccessor();
builder.Services.AddOpenFeature(cfg =>
{
    cfg.AddHostedFeatureLifecycle();
    cfg.AddContext((builder, provider) =>
    {
        // Retrieve the HttpContext from IHttpContextAccessor, ensuring it's not null.
        var context = provider.GetRequiredService<IHttpContextAccessor>().HttpContext
            ?? throw new InvalidOperationException("HttpContext is not available.");

        var userId = UserInfoHelper.GetUserId(context);
        builder.Set("user", userId);
    });
    cfg.AddInMemoryProvider(provider =>
    {
        var flagService = provider.GetRequiredService<IFeatureFlagConfigurationService>();
        return flagService.GetFlags();
    });
});

FlagConfigurationService Implementation

public class FlagConfigurationService : IFeatureFlagConfigurationService
{
    private readonly IDictionary<string, Flag> _flags;

    public FlagConfigurationService()
    {
        _flags = new Dictionary<string, Flag>
        {
            {
                "feature-a", new Flag<bool>(
                    variants: new Dictionary<string, bool>
                    {
                        { "on", true },
                        { "off", false }
                    },
                    defaultVariant: "on", context => {
                        var id = context.GetValue("user").AsString;
                        if (id == null)
                        {
                            return "on"; // Default variant
                        }

                        return id == TestUserId ? "off" : "on";
                    })
            }
        };
    }

    public Dictionary<string, Flag> GetFlags() => _flags.ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
}

[codecov]

Codecov Report

Attention: Patch coverage is 22.72727% with 51 lines in your changes missing coverage. Please review.

Project coverage is 86.66%. Comparing base (bf9de4e) to head (acd5c50).

Files with missing lines	Patch %	Lines
...ction/Providers/Memory/FeatureBuilderExtensions.cs	0.00%	42 Missing ⚠️
...ependencyInjection/OpenFeatureBuilderExtensions.cs	61.90%	7 Missing and 1 partial ⚠️
...ection/Providers/Memory/InMemoryProviderOptions.cs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #324      +/-   ##
==========================================
+ Coverage   85.91%   86.66%   +0.75%     
==========================================
  Files          34       34              
  Lines        1377     1387      +10     
  Branches      148      147       -1     
==========================================
+ Hits         1183     1202      +19     
+ Misses        162      153       -9     
  Partials       32       32              

☔ View full report in Codecov by Sentry.
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[arttonoyan]

@toddbaert @askpt @beeme1mr Hi guys, I hope you are doing well! 🖐
I recently submitted this PR that addresses the #321 issue. It's been a few days, and I wanted to kindly request that someone take a look when they have a moment.
Your feedback is greatly appreciated.
Thanks!

[askpt]

LGTM! It seems that some of the DI extension classes are missing coverage. I wonder if it is worth excluding them from code coverage for the build to pass.

[beeme1mr]

Hey @arttonoyan, sorry for the delay. Last week was a holiday in the US.

The change looks good to me. Should the examples in the readme also be updated?

[arttonoyan]

Hey @arttonoyan, sorry for the delay. Last week was a holiday in the US.

The change looks good to me. Should the examples in the readme also be updated?

Oh, no problem! I forgot about that. 😊 Yes, of course, I’ll update the documentation as well. I just wanted to get your feedback first, and I’ll make sure to update it before merging.

[toddbaert]

@ghelyar does this solve the issues you mentioned?

[ghelyar]

yes

[toddbaert]

This looks good to me and addresses the outside feedback.

My only blocker is updated documentation. Once you have that I can squash down the commits to one for you to sign off on if you want, @arttonoyan .

[arttonoyan]

This looks good to me and addresses the outside feedback.

My only blocker is updated documentation. Once you have that I can squash down the commits to one for you to sign off on if you want, @arttonoyan .

Thanks, @toddbaert ! I’ve updated the document, and I think this version is much more flexible - I’m really happy with how it’s shaping up. It’s great to see external feedback coming in; it’s been super helpful.
For this release, I also added integration tests, which made spotting issues so much easier. I’m sure we’ll keep improving it even more in the future!
cc: @beeme1mr @askpt @ghelyar

[beeme1mr]

Hey @toddbaert, it looks like this PR is ready! Could you please take a look when you have a moment?