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Builder

Definition

The Builder pattern separates the construction of a complex object from its representation, enabling different configurations via a fluent interface. In Granit, this pattern manifests in the AddGranit*() extension methods that configure services module by module.

Diagram

sequenceDiagram
    participant App as Program.cs
    participant Ext as AddGranitWolverine()
    participant Opts as WolverineMessagingOptions
    participant DI as IServiceCollection
    participant Val as ValidateOnStart

    App->>Ext: builder.AddGranitWolverine(configure?)
    Ext->>Opts: AddOptions().BindConfiguration("Wolverine")
    Ext->>Val: ValidateDataAnnotations().ValidateOnStart()
    Ext->>DI: AddScoped of ICurrentUserService
    Ext->>DI: AddSingleton of WolverineActivitySource
    opt configure provided
        Ext->>Opts: configure.Invoke(options)
    end
    Ext-->>App: IHostApplicationBuilder (fluent)

Implementation in Granit

Each module exposes an AddGranit*() extension method:

Extension	File	Receiver
`AddGranit<TModule>()`	`src/Granit.Core/Extensions/GranitHostBuilderExtensions.cs`	`IHostApplicationBuilder`
`AddGranitWolverine()`	`src/Granit.Wolverine/Extensions/WolverineHostApplicationBuilderExtensions.cs`	`IHostApplicationBuilder`
`AddGranitBackgroundJobs()`	`src/Granit.BackgroundJobs/Extensions/BackgroundJobsHostApplicationBuilderExtensions.cs`	`IHostApplicationBuilder`
`AddGranitFeatures()`	`src/Granit.Features/ServiceCollectionExtensions.cs`	`IServiceCollection`
`AddGranitLocalization()`	`src/Granit.Localization/Extensions/LocalizationServiceCollectionExtensions.cs`	`IServiceCollection`

Audit note: the signatures are not yet symmetric across modules (see finding C2 in the critical dashboard). The target is the AddOptions<T>().BindConfiguration().ValidateOnStart() pattern.

Rationale

The Builder allows each NuGet package to self-configure without the host application needing to know internal details. A single call replaces dozens of DI registration lines.

Usage example

WebApplicationBuilder builder = WebApplication.CreateBuilder(args);

// One call per module -- fluent and composable
builder.AddGranit<MyAppHostModule>();
// Internally, the ModuleLoader calls AddGranitWolverine(),
// AddGranitPersistence(), AddGranitFeatures(), etc.
// in topological dependency order

Further reading

Builder — refactoring.guru