[API Proposal]: Ioc can load configuration from config file

[soroshsabz]

Background and motivation

ITNOA

I think it is very useful to add ability to load configuration from file in Ioc, Some of values of this features

1. We can change configuration without needing recompile application.
2. In this scenario we can create multiple config set in multiple files and load them in specific situation without needing to recompile application.
3. We can change app behavior in runtime (or in deployment) without needing to reinstall app.

API Proposal

namespace Microsoft.Extensions.DependencyInjection
{
    /// <summary>
    /// Extension methods for adding services to an <see cref="IServiceCollection" />.
    /// </summary>
    public static class ServiceCollectionServiceExtensions
    {
         public static IServiceCollection AddFromConfig(this IServiceCollection services, IConfigurationSection config) {}
    }

API Usage

Ioc.Default.ConfigureServices(
      new ServiceCollection()
      .AddFromConfig(config.GetSection("Ioc"))
      .BuildServiceProvider());

Alternative Designs

            // Register services
            Ioc.Default.ConfigureServices(
                new ServiceCollection()
                .AddSingleton<IDialogService, DialogService>() //Services
                .AddSingleton<IFilesService, FilesService>()
                .AddSingleton<ISettingsService, SettingsService>()
                .AddSingleton(RestService.For<IRedditService>("https://www.reddit.com/"))
                .AddSingleton(RestService.For<IContactsService>("https://randomuser.me/"))
                .AddTransient<PostWidgetViewModel>() //ViewModels
                .AddTransient<SubredditWidgetViewModel>()
                .AddTransient<ContactsListWidgetViewModel>()
                .AddTransient<AsyncRelayCommandPageViewModel>()
                .AddTransient<IocPageViewModel>()
                .AddTransient<MessengerPageViewModel>()
                .AddTransient<ObservableObjectPageViewModel>()
                .AddTransient<ObservableValidatorPageViewModel>()
                .AddTransient<ValidationFormWidgetViewModel>()
                .AddTransient<RelayCommandPageViewModel>()
                .AddTransient<CollectionsPageViewModel>()
                .AddTransient<SamplePageViewModel>()
                .BuildServiceProvider());
        }

Risks

No response

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[soroshsabz]

related to CommunityToolkit/dotnet#328

[soroshsabz]

@dotnet/area-extensions-dependencyinjection

[soroshsabz]

@ericstj

[Sergio0694]

Without getting to the merit of this proposal per se, I would remove that Ioc.Default.ConfigureServices call from it since that's unrelated and might just be confusing, as the API described would simply be an extension for IServiceCollection 🙂

[ghost]

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

---

Background and motivation

ITNOA

I think it is very useful to add ability to load configuration from file in Ioc, Some of values of this features

1. We can change configuration without needing recompile application.
2. In this scenario we can create multiple config set in multiple files and load them in specific situation without needing to recompile application.
3. We can change app behavior in runtime (or in deployment) without needing to reinstall app.

API Proposal

namespace Microsoft.Extensions.DependencyInjection
{
    /// <summary>
    /// Extension methods for adding services to an <see cref="IServiceCollection" />.
    /// </summary>
    public static class ServiceCollectionServiceExtensions
    {
         public static IServiceCollection AddFromConfig(this IServiceCollection services, IConfigurationSection config) {}
    }

API Usage

Ioc.Default.ConfigureServices(
      new ServiceCollection()
      .AddFromConfig(config.GetSection("Ioc"))
      .BuildServiceProvider());

Alternative Designs

            // Register services
            Ioc.Default.ConfigureServices(
                new ServiceCollection()
                .AddSingleton<IDialogService, DialogService>() //Services
                .AddSingleton<IFilesService, FilesService>()
                .AddSingleton<ISettingsService, SettingsService>()
                .AddSingleton(RestService.For<IRedditService>("https://www.reddit.com/"))
                .AddSingleton(RestService.For<IContactsService>("https://randomuser.me/"))
                .AddTransient<PostWidgetViewModel>() //ViewModels
                .AddTransient<SubredditWidgetViewModel>()
                .AddTransient<ContactsListWidgetViewModel>()
                .AddTransient<AsyncRelayCommandPageViewModel>()
                .AddTransient<IocPageViewModel>()
                .AddTransient<MessengerPageViewModel>()
                .AddTransient<ObservableObjectPageViewModel>()
                .AddTransient<ObservableValidatorPageViewModel>()
                .AddTransient<ValidationFormWidgetViewModel>()
                .AddTransient<RelayCommandPageViewModel>()
                .AddTransient<CollectionsPageViewModel>()
                .AddTransient<SamplePageViewModel>()
                .BuildServiceProvider());
        }

Risks

No response

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

[eerhardt]

I don't believe this is a route we want to take in the core libraries. It completely removes any trimming / AOT / etc. capabilities in the application. Also, the information in the configuration is strings, which then the library would need to do the assembly loading and Type resolving from strings. This would break if the assemblies aren't referenced and in the .deps.json file.

This sounds like a great extension someone can build outside of the core Microsoft.Extensions libraries, if it is needed. It doesn't need to be in the core libraries.

We can change app behavior in runtime (or in deployment) without needing to reinstall app.

The DI container is static for the lifetime of the app. You can't make a change to the file, and then expect the running app to rebuild the ServiceProvider with the new services. The process needs to terminate and restart in order for this to happen.

cc @davidfowl

[davidfowl]

Agree this should be an external library, not built in.

[soroshsabz]

@Sergio0694 As you can see @davidfowl says this extension must be external of runtime, so I think it is go to the CommunityToolkit, Did you agree with me?

[soroshsabz]

The DI container is static for the lifetime of the app. You can't make a change to the file, and then expect the running app to rebuild the ServiceProvider with the new services. The process needs to terminate and restart in order for this to happen.

@eerhardt I say with this feature we does not need to recompile it, as you says it is require to restart app, and I agree with you, but rebuilding is very worst than re-running ;)

[Sergio0694]

@soroshsabz What David said is absolutely valid, but that doesn't mean this belongs in the MVVM Toolkit — it simply doesn't belong in either project. I share the concerns that Eric raised with respect to trimming etc., but most importantly, as I've already said — the MVVM Toolkit doesn't have a dependency on Microsoft.Extensions.DependencyInjection, so there's no way this extension could live there anyway even if we wanted to. And taking that dependency would be out of the question, as it would add unnecessary binary size to consuming projects that are using other service providers. For instance, it would be an immediate game breaker for us in the Microsoft Store. If you wanted that extension for yourself, you should just define it in your own project, or create your own library to host it if you wanted to share it with others too 🙂

[davidfowl]

Maybe https://github.com/khellang/Scrutor is a reasonable place. Try asking on that repo if the author is willing. Otherwise just make a new package and put it on nuget.