Stashbox.Extensions.Hosting 5.5.0

stashbox-extensions-dependencyinjection

This repository contains Stashbox integrations for ASP.NET Core, .NET Generic Host and simple ServiceCollection based applications.

Package	Version
Stashbox.Extensions.DependencyInjection
Stashbox.Extensions.Hosting
Stashbox.AspNetCore.Hosting
Stashbox.AspNetCore.Multitenant
Stashbox.AspNetCore.Testing

Options turned on by default:

• Automatic tracking and disposal of IDisposable and IAsyncDisposable services.
• Lifetime validation for Developement environments, but can be extended to all environment types.

Table of Contents

• ASP.NET Core
  • Controller / View activation
  • Multitenant
  • Testing
• .NET Generic Host
• ServiceCollection Based Applications
• Additional IServiceCollection Extensions
• IServiceProvider Extensions

ASP.NET Core

The following example shows how you can integrate Stashbox (with the Stashbox.Extensions.Hosting package) as the default IServiceProvider implementation into your ASP.NET Core application:

var builder = WebApplication.CreateBuilder(args);

builder.Host.UseStashbox(container => // Optional configuration options.
{
    container.Configure(options => { /*...*/ });
});

builder.Host.ConfigureContainer<IStashboxContainer>((context, container) =>
{
    // Execute container validation in development mode.
    if (context.HostingEnvironment.IsDevelopment())
        container.Validate();
});

Controller / View activation

By default the ASP.NET Core framework uses the DefaultControllerActivator to instantiate controllers, but it uses the ServiceProvider only for instantiating their constructor dependencies. This behaviour could hide important errors Stashbox would throw in case of a misconfiguration, so it's recommended to let Stashbox activate your controllers and views.

You can enable this by adding the following options to your service configuration:

// For controllers only.
builder.Services.AddControllers()
    .AddControllersAsServices();
    
// For controllers and views.
builder.Services.AddControllersWithViews()
    .AddControllersAsServices()
    .AddViewComponentsAsServices();

Multitenant

The Stashbox.AspNetCore.Multitenant package provides support for multi-tenant applications.

It's responsible for the following tasks:

1. Create / maintain the application level Root Container. This container is used to hold the default service registrations for your application.
2. Configure / maintain tenant specific child containers. These containers are used to override the default services with tenant specific registrations.
3. Tenant identification. Determines the tenant Id based on the current context. To achieve that, you have to provide an ITenantIdExtractor implementation.

// The type used to extract the current tenant identifier.
// This implementation shows how to extract the tenant id from a HTTP header.
public class HttpHeaderTenantIdExtractor : ITenantIdExtractor
{
    public Task<object> GetTenantIdAsync(HttpContext context)
    {
        if (!context.Request.Headers.TryGetValue("TENANT-ID", out var value))
            return Task.FromResult<object>(null);

        return Task.FromResult<object>(value.First());
    }
}

var builder = WebApplication.CreateBuilder(args);
builder.Host.UseStashboxMultitenant<HttpHeaderTenantIdExtractor>(
    options => // Multi-tenant configuration options.
{
    // The default service registration, it registers into the root container.
    // It also could be registered into the default 
    // service collection with the ConfigureServices() API.
    options.RootContainer.Register<IDependency, DefaultDependency>();

    // Configure tenants.
    options.ConfigureTenant("TenantA", tenant => 
        // Register tenant specific service override
        tenant.Register<IDependency, TenantASpecificDependency>());

    options.ConfigureTenant("TenantB", tenant => 
        // Register tenant specific service override
        tenant.Register<IDependency, TenantBSpecificDependency>());
});

// The container parameter is the tenant distributor itself.
// Calling its Validate() method will verify the root container and each tenant.
builder.Host.ConfigureContainer<IStashboxContainer>((context, container) =>
{
    // Validate the root container and all tenants.
    if (context.HostingEnvironment.IsDevelopment())
        container.Validate();
});

With this example setup, you can differentiate tenants in a per-request basis identified by a HTTP header, where every tenant gets their overridden services.

Testing

The Stashbox.AspNetCore.Testing package provides a specialized WebApplicationFactory<T> based on the Stashbox.AspNetCore.Multitenant package.

The original WebApplicationFactory<T> supports the injection of mock services, but it recreates the hosting application on each WithWebHostBuilder() call, which - when used heavily - can impact the test execution's performance.

In contrast of WebApplicationFactory<T>, the StashboxWebApplicationFactory<T> uses tenant child containers from the Stashbox.AspNetCore.Multitenant package to distinguish mock services. This solution doesn't require the recreation of the hosting application for each mocking session.

Let's see a usage example of WebApplicationFactory<T>:

public class ExampleTests : IClassFixture<WebApplicationFactory<Program>>
{
    private readonly WebApplicationFactory<Program> factory;

    public ExampleTests(WebApplicationFactory<Program> factory)
    {
        this.factory = factory;
    }

    [Fact]
    public async Task Get_Example_Endpoint()
    {
        var client = this.factory.WithWebHostBuilder(builder =>
        {
            builder.ConfigureTestServices(services =>
            {
                // service override with mock
                services.AddScoped<IDependency, MockDependency>();
            });
        })
        .CreateClient();

        var response = await client.GetAsync("/example");

        response.EnsureSuccessStatusCode();
        Assert.Equal("example body", 
            await response.Content.ReadAsStringAsync());
    }
}

The same functionality with StashboxWebApplicationFactory<T> would look like this:

public class ExampleTests : IClassFixture<StashboxWebApplicationFactory<Program>>
{
    private readonly StashboxWebApplicationFactory<Program> factory;

    public ExampleTests(StashboxWebApplicationFactory<Program> factory)
    {
        this.factory = factory;
    }

    [Fact]
    public async Task Get_Example_Endpoint()
    {
        var client = this.factory.StashClient((services, httpClientOptions) =>
        {
            // service override with mock
            services.AddScoped<IDependency, MockDependency>();
        });

        var response = await client.GetAsync("/example");

        response.EnsureSuccessStatusCode();
        Assert.Equal("example body", 
            await response.Content.ReadAsStringAsync());
    }
}

They look similar, the main difference is how they actually work behind the scenes.

While WebApplicationFactory<Program> creates a new hosting application upon each WithWebHostBuilder() call to distinguish mock services from real ones, StashboxWebApplicationFactory<Program> uses a single host and each StashClient() call creates a child Stashbox container to maintain mock services.

The returning HttpClient signals the application to use the previously created child container for service resolution.

There's also a difference in their performance:

BenchmarkDotNet=v0.13.4, OS=Windows 10 (10.0.19044.2486/21H2/November2021Update)
AMD Ryzen 9 3900X, 1 CPU, 24 logical and 12 physical cores
.NET SDK=7.0.100
[Host]     : .NET 7.0.0 (7.0.22.51805), X64 RyuJIT AVX2
DefaultJob : .NET 7.0.0 (7.0.22.51805), X64 RyuJIT AVX2

|                                    Method |         Mean |        Error |       StdDev | Ratio |    Gen0 |    Gen1 | Allocated | Alloc Ratio |
|------------------------------------------ |-------------:|-------------:|-------------:|------:|--------:|--------:|----------:|------------:|
|        WebApplicationFactory_CreateClient | 22,338.65 us | 2,430.543 us | 7,166.511 us | 1.000 | 93.7500 | 23.4375 | 775.53 KB |       1.000 |
| StashboxWebApplicationFactory_StashClient |     10.10 us |     0.191 us |     0.204 us | 0.001 |  0.5035 |  0.2441 |   4.16 KB |       0.005 |

You can access the underlying tenant container by providing your own tenantId.

var tenantId = "tenant_id";
var client = this.factory.StashClient((services, httpClientOptions) =>
{
    // ...
}, tenantId);

var tenantContainer = this.factory.RootContainer.GetChildContainer(tenantId);

Note: Here you can read more about Stashbox child containers.

.NET Generic Host

The following example adds Stashbox (with the Stashbox.Extensions.Hosting package) as the default IServiceProvider implementation into your .NET Generic Host application:

public class Program
{
    public static async Task Main(string[] args)
    {
        var host = Host.CreateDefaultBuilder(args)
            .UseStashbox(container => // Optional configuration options.
            {
                container.Configure(options => { /*...*/ });
            })
            .ConfigureContainer<IStashboxContainer>((context, container) =>
            {
                // Execute container validation in development mode.
                if (context.HostingEnvironment.IsDevelopment())
                    container.Validate();
            })
            .ConfigureServices((context, services) =>
            {
                services.AddHostedService<Service>();
            }).Build();

        await host.RunAsync();
    }
}

ServiceCollection Based Applications

With the Stashbox.Extensions.Dependencyinjection package you can replace Microsoft's built-in dependency injection container with Stashbox. This package contains the core functionality used by the Stashbox.Extensions.Hosting, Stashbox.AspNetCore.Hosting and Stashbox.AspNetCore.Multitenant packages.

The following example shows how you can use this integration:

public class Program
{
    public static async Task Main(string[] args)
    {
        // Create the service collection.
        var services = new ServiceCollection();

        // Configure your service collection.
        services.AddLogging();
        services.AddOptions();

        // Add your services.
        services.AddScoped<IService, Service>();

        // Integrate Stashbox with the collection and get the ServiceProvider.
        var serviceProvider = services.UseStashbox(container => // Optional configuration options.
        {
            container.Configure(config => config.WithLifetimeValidation());
        });

        // Start using the application.
        using var scope = serviceProvider.CreateScope();
        var service = scope.ServiceProvider.GetService<IService>();
        await service.DoSomethingAsync();
    }
}

Or you can use your own StashboxContainer to integrate with the ServiceCollection:

public class Program
{
    public static async Task Main(string[] args)
    {
        // Create your container.
        var container = new StashboxContainer(config => // Optional configuration options.
        {
            config.WithLifetimeValidation();
        });

        // Create the service collection.
        var services = new ServiceCollection();

        // Configure your service collection.
        services.AddLogging();
        services.AddOptions();

        // Add your services.
        services.AddScoped<IService, Service>();

        // Or add them through Stashbox.
        container.RegisterScoped<IService, Service>();

        // Integrate Stashbox with the collection.
        services.UseStashbox(container);

        // Execute a dependency tree validation.
        container.Validate();

        // Start using the application.
        await using var scope = container.BeginScope();
        var service = scope.Resolve<IService>();
        await service.DoSomethingAsync();
    }
}

Additional IServiceCollection Extensions

Most of Stashbox's service registration functionalities are available as extension methods of IServiceCollection.

• Named service registration:

  class Service2 : IService2
  {
      private readonly IService service;
  
      public Service2(IService service) 
      {
          this.service = service;
      }
  }
  
  var services = new ServiceCollection();
  services.AddTransient<IService, Service>(); // Name-less registration.
  services.AddTransient<IService, AnotherService>("serviceName"); // Register dependency with name.
  services.AddTransient<IService2, Service2>(config => 
    // Inject the named service as dependency.
    config.WithDependencyBinding<IService>(
        "serviceName" // Name of the dependency.
    ));
  

• Service configuration with Stashbox's Fluent Registration API:

  var services = new ServiceCollection();
  services.AddTransient<IService, Service>(config => 
    config.WithFactory<IDependency>(dependency => new Service(dependency)).AsImplementedTypes());
  

• Service decoration:

  class ServiceDecorator : IService
  {
      private readonly IService decorated;
  
      public ServiceDecorator(IService service)
      {
          this.decorated = service;
      }
  }
  
  var services = new ServiceCollection();
  services.AddTransient<IService, Service>();
  services.Decorate<IService, ServiceDecorator>();
  

• Assembly registration:

  var services = new ServiceCollection();
  services.ScanAssemblyOf<IService>(
    // Set a filter for which types should be excluded/included in the registration process.
    // In this case, only the publicly available types are selected from the assembly.
    type => type.IsPublic, 
    // The service type selector. Used to filter which interface or base types the implementation should be mapped to.
    // In this case, we are registering only by interfaces.
    (implementationType, serviceType) => serviceType.IsInterface,
    false, // Do not map services to themselves. E.g: Service -> Service.
    config =>
    {
        // Register IService instances as scoped.
        if (config.ServiceType == typeof(IService))
            config.WithScopedLifetime();
    }
  );
  

• Composition root:

  class CompositionRoot : ICompositionRoot
  {
      public void Compose(IStashboxContainer container)
      {
          container.Register<IService, Service>();
      }
  }
  
  var services = new ServiceCollection();
  services.ComposeBy<CompositionRoot>();
  
  // Or let Stashbox find all composition roots in an assembly.
  services.ComposeAssembly(typeof(CompositionRoot).Assembly);
  

IServiceProvider Extensions

Named resolution is available on IServiceProvider through the following extension methods:

• GetService<T>(object name)
• GetService(Type serviceType, object name)
• GetRequiredService<T>(object name)
• GetRequiredService(Type serviceType, object name)
• GetServices<T>(object name)
• GetServices(Type serviceType, object name)

class Service2 : IService2
{
    private readonly IService service;
    
    public Service2(IService service) 
    {
        this.service = service;
    }
}
  
var services = new ServiceCollection();
services.AddTransient<IService, Service>(); // Name-less registration.
services.AddTransient<IService, AnotherService>("serviceName"); // Register dependency with name.

var serviceProvider = services.UseStashbox();

var service = serviceProvider.GetRequiredService<IService>(); // type: Service
var anotherService = serviceProvider.GetRequiredService<IService>("serviceName"); // type: AnotherService