.Net: Import plugins with mixed prompt and native functions (avoiding creating a plugin for each function)

[markwallace-microsoft]

Discussed in #8818

^{Originally posted by gsubiran September 16, 2024}
Hey! I've been working with SK for some time, and I'm having a bit of trouble handling the import of plugin functions. Here's what I've encountered:

When you want to import a plugin with prompt functions (formerly known as semantic functions), you can use:

kernel.ImportPluginFromPromptDirectory("Plugins/SomeSpecificPlugin", "PluginName");

On the other hand, if you want to import a plugin with native functions, a simple way to do that is:

kernel.ImportPluginFromType<Plugins.MyNativeFunctions>("PluginName");

That’s pretty straightforward. However, the problem arises when you want to combine native and prompt functions in the same plugin. I found that there is no easy way to do this. Additionally, if you want to separate native functions into different classes, you end up creating a new plugin for each native function due to the same issue.

I’d appreciate some advice if I’m missing something here, but I believe the goal of plugins should be to group related native and semantic functions.

My Approach
I created a class called CustomKernelExtensions to make it easier to import both native and prompt functions into the same plugin by calling:

kernel.CustomImportPlugin("PluginName");

(For simplicity, assume CustomKernelExtensions.cs is placed in the "Plugins" directory, and the plugin name must match the specific plugin folder name.)

Here’s the code for the CustomKernelExtensions class:

internal static class CustomKernelExtensions
{
    private static IEnumerable<KernelFunction> CreatePromptFunctions(Kernel kernel, string pluginName)
    {
        var scanDirectory = Path.Combine(Environment.CurrentDirectory, nameof(Plugins), pluginName);

        // Creating plugin from directory (but not importing it into the kernel)
        return kernel.CreatePluginFromPromptDirectory(scanDirectory);
    }

    private static IEnumerable<KernelFunction> CreateNativeFunctions(Kernel kernel, string pluginName)
    {
        List<KernelFunction> result = new List<KernelFunction>();

        string namespaceToGetPlugins = typeof(CustomKernelExtensions).Namespace!;
        namespaceToGetPlugins = $"{namespaceToGetPlugins}.{pluginName}";

        foreach (Type type in Assembly.GetExecutingAssembly().GetTypes().Where(x => x.Namespace != null && x.Namespace.StartsWith(namespaceToGetPlugins)))
        {
            var containsAnyNativeFunction = type.GetMethods().Any(m => m.GetCustomAttributes(typeof(KernelFunctionAttribute), false).Length > 0);

            if (containsAnyNativeFunction)
            {
                string functionName = type.FullName!.Replace(type.Assembly!.GetName().Name!, string.Empty).Trim('.').Replace($"{nameof(Plugins)}.", string.Empty);

                // Creating an instance, ensuring to inject dependencies
                var instance = ActivatorUtilities.CreateInstance(kernel.Services, type);

                // Creating plugin from object (but not importing it into the kernel)
                result.AddRange(kernel.CreatePluginFromObject(instance, type.Name!));
            }
        }

        return result;
    }

    internal static void CustomImportPlugin(this Kernel kernel, string pluginName)
    {
        if (string.IsNullOrWhiteSpace(pluginName))
            throw new ArgumentNullException(nameof(pluginName), "You must provide a plugin name to import.");

        // Merging all kernel functions (native and prompt) into the same plugin
        kernel.ImportPluginFromFunctions(pluginName,
            CreatePromptFunctions(kernel, pluginName)
            .Concat(CreateNativeFunctions(kernel, pluginName)));
    }
}

Does anyone have any feedback on this approach? I’m wondering if I’m overcomplicating things. Is there a simpler way to achieve the same result? I would appreciate any insights or suggestions!