Remora.Plugins

Remora.Plugins is a simple plugin system for .NET, providing a dynamic pluggable framework for your applications. In short, class libraries can be written as standalone packages and loaded at runtime as integrated parts of your application, allowing loose coupling and easily swappable components. The plugin system is designed around Microsoft's dependency injection framework.

Usage

Creating a plugin is as simple as creating a class library project, and annotating the assembly with an attribute denoting the type used as a plugin descriptor. The descriptor acts as the entry point of the plugin, as well as an encapsulation point for information about it.

Generally, plugins should only reference Remora.Plugins.Abstractions, while the main application should reference and use Remora.Plugins.

[assembly: RemoraPlugin(typeof(MyPlugin))]

public sealed class MyPlugin : PluginDescriptor
{
    /// <inheritdoc />
    public override string Name => "My Plugin";

    /// <inheritdoc />
    public override string Description => "My plugin that does a thing.";

    /// <inheritdoc/>
    public override Result ConfigureServices(IServiceCollection serviceCollection)
    {
        serviceCollection
            .AddScoped<MyService>();

        return Result.FromSuccess();
    }

    /// <inheritdoc />
    public override async ValueTask<Result> InitializeAsync(IServiceProvider serviceProvider)
    {
        var myService = serviceProvider.GetRequiredService<MyService>();
        var doThing = await myService.DoTheThingAsync();
        if (!doThing.IsSuccess)
        {
            return doThing;
        }

        return Result.FromSuccess();
    }
}

Loading plugins in your application is equally simple. The example below is perhaps a little convoluted, but shows the flexibility of the system.

var pluginService = new PluginService();

var serviceCollection = new ServiceCollection()
    .AddSingleton(pluginService);

var pluginTree = pluginService.LoadPluginTree();
var configurePlugins = pluginTree.ConfigureServices(serviceCollection);
if (!configurePlugins.IsSuccess)
{
    // check configurePlugins.Error to figure out why
    return;
}

_services = serviceCollection.BuildServiceProvider();

var initializePlugins = await pluginTree.InitializeAsync(_services, ct);
if (!initializePlugins.IsSuccess)
{
    // check initializePlugins.Error to figure out why
    return;
}

var migratePlugins = await pluginTree.MigrateAsync(_services, ct);
if (!migratePlugins.IsSuccess)
{
    // check migratePlugins.Error to figure out why
    return;
}

Plugins should be designed in such a way that a registration or initialization failure does not corrupt the application.

Building

The library does not require anything out of the ordinary to compile.

cd $SOLUTION_DIR
dotnet build
dotnet pack -c Release

Downloading

Get it on NuGet.