[API Proposal]: Add extensions to create an OptionsBuilder with ValidateOnStart support

[steveharter]

Background and motivation

Based on cloud native scenarios, these extensions methods were used and they make sense to add to the System.Microsoft.Extensions.Options.library.

Note that in cloud native, these methods were called "AddValidatedOptions"; here they are called "AddValidateOnStartOptions".

API Proposal

namespace namespace Microsoft.Extensions.DependencyInjection;

public static partial class OptionsServiceCollectionExtensions
{
    // Calls ValidateOnStart()
+   public static OptionsBuilder<TOptions> AddValidateOnStartOptions
+       <[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>
+        (this IServiceCollection services,
+        string? name = null)
+        where TOptions : class
    {
        // Simple wrapper like this:
        return new OptionsBuilder<TOptions>(services, name ?? Options.DefaultName).ValidateOnStart();
    }

    // Supports IValidateOptions and call ValidateOnStart() above
+   public static OptionsBuilder<TOptions> AddValidateOnStartOptions<
+       [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions,
+       [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TValidateOptions>(
+       this IServiceCollection services,
+       string? name = null)
+       where TOptions : class
+       where TValidateOptions : class, IValidateOptions<TOptions>
      {
         // Simple wrapper like this:
         services.AddOptions().TryAddEnumerable(ServiceDescriptor.Singleton<IValidateOptions<TOptions>, TValidateOptions>());
         return new OptionsBuilder<TOptions>(services, name ?? Options.DefaultName).ValidateOnStart();
      }

API Usage

// Before:
IHostBuilder builder = ...
builder.services
    .AddOptions<MyOptions>()
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .Validate(o => o.MySetting == true)
    .ValidateOnStart();
// After:
IHostBuilder builder = ...
builder.Services
    .AddValidateOnStartOptions<MyOptions>()
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .Validate(o => o.MySetting == true);

// Before:
IHostBuilder builder = ...
builder.Services
    .AddOptions<MyOptions>()
    .AddSingleton<IValidateOptions<MyOptions>>(new MyOptionsValidator(builder .Name)) // or TryAddEnumerable
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .ValidateOnStart();
// After:
IHostBuilder builder = ...
builder.Services.
    .AddValidateOnStartOptions<MyOptions, MyOptionsValidator>(builder.Name))
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))

Alternative Designs

No response

Risks

No response

[ghost]

Tagging subscribers to this area: @dotnet/area-extensions-dependencyinjection
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Issue Details

---

Background and motivation

Based on cloud native scenarios, these extensions methods were used and they make sense to add to the System.Microsoft.Extensions.DependencyInjection library.

Note that in cloud native, these methods were called "AddValidatedOptions"; here they are called "AddValidateOnStartOptions".

API Proposal

namespace namespace Microsoft.Extensions.DependencyInjection;

public static partial class OptionsBuilderExtensions
{
    // The one existing extension method:
    public static OptionsBuilder<TOptions> ValidateOnStart
        <[DynamicallyAccessedMembers(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.
            PublicParameterlessConstructor)] TOptions>
        (this OptionsBuilder<TOptions> optionsBuilder)
        where TOptions : class;

    // New one to call ValidateOnStart() above
+   public static OptionsBuilder<TOptions> AddValidateOnStartOptions
+       <[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>
+        (this IServiceCollection services,
+        string? name = null)
+        where TOptions : class
    {
        // Simple wrapper like this:
        return new OptionsBuilder<TOptions>(services, name ?? Options.DefaultName).ValidateOnStart();
    }

    // New one to support IValidateOptions and call ValidateOnStart() above
+   public static OptionsBuilder<TOptions> AddValidateOnStartOptions<
+       [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions,
+       [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TValidateOptions>(
+       this IServiceCollection services,
+       string? name = null)
+       where TOptions : class
+       where TValidateOptions : class, IValidateOptions<TOptions>
      {
         // Simple wrapper like this:
         services.AddOptions().TryAddEnumerable(ServiceDescriptor.Singleton<IValidateOptions<TOptions>, TValidateOptions>());
         return new OptionsBuilder<TOptions>(services, name ?? Options.DefaultName).ValidateOnStart();
      }

API Usage

// Before:
IHostBuilder builder = ...
builder.services
    .AddOptions<MyOptions>()
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .Validate(o => o.MySetting == true)
    .ValidateOnStart();
// After:
IHostBuilder builder = ...
builder.Services
    .AddValidateOnStartOptions<MyOptions>()
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .Validate(o => o.MySetting == true);

// Before:
IHostBuilder builder = ...
builder.Services
    .AddOptions<MyOptions>()
    .AddSingleton<IValidateOptions<MyOptions>>(new MyOptionsValidator(builder .Name)) // or TryAddEnumerable
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))
    .ValidateOnStart();
// After:
IHostBuilder builder = ...
builder.Services.
    .AddValidateOnStartOptions<MyOptions, MyOptionsValidator>(builder.Name))
    .Bind(builder.Configuration.GetSection(MyConfigOptions.MyConfig))

Alternative Designs

No response

Risks

No response

Author:	steveharter
Assignees:	steveharter
Labels:	api-suggestion, area-Extensions-DependencyInjection
Milestone:	-

[steveharter]

cc @geeknoid @tekian @rafal-mz to match similar cloud native functionality

[ericstj]

@steveharter you mention

add to the System.Microsoft.Extensions.DependencyInjection library.

But I think we want to add to OptionsBuilderExtensions in the Microsoft.Extensions.Options library.

[eerhardt]

<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>

Why does the proposal have DynamicallyAccessedMemberTypes.All on the TOptions? I believe it should only need DynamicallyAccessedMemberTypes.PublicParameterlessConstructor.

[terrajobst]

Video

• Let's call it AddOptionsWithValidateOnStart() to make it clear that it does both AddOptions and calls ValidateOnStart.

namespace namespace Microsoft.Extensions.DependencyInjection;

public static partial class OptionsBuilderExtensions
{
    // The one existing extension method:
    // public static OptionsBuilder<TOptions> ValidateOnStart
    //     <[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] TOptions>
    //     (this OptionsBuilder<TOptions> optionsBuilder)
    //     where TOptions : class;

    // New one to call ValidateOnStart() above
    public static OptionsBuilder<TOptions> AddOptionsWithValidateOnStart
        <[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>
         (this IServiceCollection services,
         string? name = null)
         where TOptions : class;

    // New one to support IValidateOptions and call ValidateOnStart() above
    public static OptionsBuilder<TOptions> AddOptionsWithValidateOnStart<
        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions,
        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TValidateOptions>(
        this IServiceCollection services,
        string? name = null)
        where TOptions : class
        where TValidateOptions : class, IValidateOptions<TOptions>;
}

[halter73]

@steveharter I just noticed that this proposal put the new AddOptions... methods in OptionsBuilderExtensions. Shouldn't these be in OptionsServiceCollectionExtensions instead?