MartinDrozdik.DDD.Options 0.10.0

DDD Options - Configuration That Fails Fast

IOptions<T> with a section convention and FluentValidation, based on MartinDrozdik.DDD. No ASP.NET Core dependency, so your business layer can define and register its own options. Check the demo.

Installation

dotnet add package MartinDrozdik.DDD.Options

Also check this repos' DDD Claude Code plugin for better AI code generation.

Options

Leverages IOptions<T> with FluentValidation for configuration validation and automatic binding.

Configured to fail fast if your configuration is invalid. No more "wOrKs On My MaChInE".

public class InvoiceOptions : IValidatedAppOptions<InvoiceOptions>
{
    public static string Section => "App:Invoice"; // Simple binding from config (appsettings etc.)

    // FluentValidation validator, because attributes are for suckers
    public static AbstractValidator<InvoiceOptions> Validator { get; } = new OptionsValidator();

    // Your actual options properties:
    public required int StartingId { get; init; }
    public required string DefaultName { get; init; }
    
    private class OptionsValidator : AbstractValidator<InvoiceOptions>
    {
        public OptionsValidator()
        {
            RuleFor(e => e.StartingId).GreaterThanOrEqualTo(0);
            RuleFor(e => e.DefaultName).NotNull().NotEmpty();
        }
    }
}

// Register it:
builder.Services.AddValidatedAppOptions<InvoiceOptions>();

For simpler options without validation:

public class SimpleOptions : IAppOptions
{
    public static string Section => "App:Simple";
    public required string Value { get; init; }
}

builder.Services.AddAppOptions<SimpleOptions>();

Both bind strictly (ErrorOnUnknownConfiguration = true) and validate on start, so a typo in a config key is a startup failure rather than a silent default.

To read options during startup, before the container exists, go through the configuration manager:

var db = builder.Configuration.GetRequiredValidatedOptions<DatabaseOptions>();
// also: GetOptions<T>(), GetRequiredOptions<T>(), GetValidatedOptions<T>()

Testing

Goes well with MartinDrozdik.DDD.Testing smoke tests, since options are validated on startup.

public class DemoAppSmokeTests(ITestOutputHelper testOutputHelper)
    : WebApplicationSmokeTests<Program>(new DemoAppBuilder(testOutputHelper));