Laravel Pennant

 Laravel Pennant is a package created by the Laravel team that will arrive with Laravel 10 provides Feature Flags for your applications.

Feature flags enable you to incrementally roll out new application features with confidence, A/B test new interface designs, compliment a trunk-based development strategy, and much more.

This package is the latest in the lineup of official packages provided by the core team and means that we now have a well-built and well-tested package that provides us with some great functionality.

Breaking down the package's features, we can look into what this package gives us.

Creating a new feature is a simple process of defining it with your AppServiceProvider like so:

public function boot(): void
{
    Feature::define('beta-testers', fn (User $user) => match (true) {
        $user->isBetaTester() => true,
        default => false,
    });
}

This is a super clean and easy way to define features in your application. However, you can also use a class-based approach to your features:

class BetaTesters
{
    public function resolve(User $user): mixed
    {
        return match (true) {
            $user->isBetaTester() => true,
            default => false,
        };
    }
}

Looking through the documentation, I see that there will be many exciting ways this could be used. Let's look at one example from the documentation and see what we can do with it.

class PodcastController
{
    public function index(Request $request): Response
    {
        return Feature::when(NewApi::class,
            fn () => $this->resolveNewApiResponse($request),
            fn () => $this->resolveLegacyApiResponse($request),
        );
    }
}

Moving forward, this works well for a versioned API - you can control where the request is meant to go based on whether the user has access. Let's expand upon this example.

class PodcastController
{
    public function __construct(
        private readonly RedirectAction $action,
    ) {}
 
    public function index(Request $request): Response
    {
        return Feature::when(BetaTester::class,
            fn () => $this->action->handle('v2'),
            fn () => $this->action->handle('v1'),
        );
    }
}

We could use our action to redirect to the correct API route based on whether or not the use is a beta tester. We could move this a layer higher into middleware to make this simpler.

class VersionMiddleware
{
    public function handle(Request $request, Closure $next): mixed
    {
        if (Feature::active('beta-tester')) {
            return new RedirectResponse(
                uri: 'generate the url here',
            );
        }
 
        return $next($request);
    }
}

As you can imagine, what you will be able to do with this package will only be limited by your imagination. I cannot wait to use this package and see what improvements it allows me to add to my application.