.Net: New CreateFromType and CreateMetadataFromType methods

dotnet/src/SemanticKernel.Core/Functions/KernelFunctionFromMethod.cs

@@ -100,6 +100,66 @@ public static KernelFunction Create(
         return result;
     }
 
+    /// <summary>
+    /// Creates a <see cref="KernelFunctionMetadata"/> instance for a method, specified via an <see cref="MethodInfo"/> instance.
+    /// </summary>
+    /// <param name="method">The method to be represented via the created <see cref="KernelFunction"/>.</param>
+    /// <param name="functionName">The name to use for the function. If null, it will default to one derived from the method represented by <paramref name="method"/>.</param>
+    /// <param name="description">The description to use for the function. If null, it will default to one derived from the method represented by <paramref name="method"/>, if possible (e.g. via a <see cref="DescriptionAttribute"/> on the method).</param>
+    /// <param name="parameters">Optional parameter descriptions. If null, it will default to one derived from the method represented by <paramref name="method"/>.</param>
+    /// <param name="returnParameter">Optional return parameter description. If null, it will default to one derived from the method represented by <paramref name="method"/>.</param>
+    /// <param name="loggerFactory">The <see cref="ILoggerFactory"/> to use for logging. If null, no logging will be performed.</param>
+    /// <returns>The created <see cref="KernelFunction"/> wrapper for <paramref name="method"/>.</returns>
+    [Experimental("SKEXP0001")]
+    public static KernelFunctionMetadata CreateMetadata(
+        MethodInfo method,
+        string? functionName = null,
+        string? description = null,
+        IEnumerable<KernelParameterMetadata>? parameters = null,
+        KernelReturnParameterMetadata? returnParameter = null,
+        ILoggerFactory? loggerFactory = null)
+        => CreateMetadata(
+            method,
+            new KernelFunctionFromMethodOptions
+            {
+                FunctionName = functionName,
+                Description = description,
+                Parameters = parameters,
+                ReturnParameter = returnParameter,
+                LoggerFactory = loggerFactory
+            });
+
+    /// <summary>
+    /// Creates a <see cref="KernelFunctionMetadata"/> instance for a method, specified via an <see cref="MethodInfo"/> instance.
+    /// </summary>
+    /// <param name="method">The method to be represented via the created <see cref="KernelFunction"/>.</param>
+    /// <param name="options">Optional function creation options.</param>
+    /// <returns>The created <see cref="KernelFunction"/> wrapper for <paramref name="method"/>.</returns>
+    [Experimental("SKEXP0001")]
+    public static KernelFunctionMetadata CreateMetadata(
+        MethodInfo method,
+        KernelFunctionFromMethodOptions? options = default)
+    {
+        Verify.NotNull(method);
+
+        MethodDetails methodDetails = GetMethodDetails(options?.FunctionName, method, null);
+        var result = new KernelFunctionFromMethod(
+            methodDetails.Function,
+            methodDetails.Name,
+            options?.Description ?? methodDetails.Description,
+            options?.Parameters?.ToList() ?? methodDetails.Parameters,
+            options?.ReturnParameter ?? methodDetails.ReturnParameter,
+            options?.AdditionalMetadata);
+
+        if (options?.LoggerFactory?.CreateLogger(method.DeclaringType ?? typeof(KernelFunctionFromPrompt)) is ILogger logger &&
+            logger.IsEnabled(LogLevel.Trace))
+        {
+            logger.LogTrace("Created KernelFunctionMetadata '{Name}' for '{MethodName}'", result.Name, method.Name);
+        }
+
+        return result.Metadata;
+    }
+
     /// <inheritdoc/>
     protected override ValueTask<FunctionResult> InvokeCoreAsync(
         Kernel kernel,

dotnet/src/SemanticKernel.Core/Functions/KernelFunctionMetadataFactory.cs

@@ -0,0 +1,51 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.SemanticKernel;
+
+/// <summary>
+/// Provides factory methods for creating collections of <see cref="KernelFunctionMetadata"/>, such as
+/// those backed by a prompt to be submitted to an LLM or those backed by a .NET method.
+/// </summary>
+[Experimental("SKEXP0001")]
+public static class KernelFunctionMetadataFactory
+{
+    /// <summary>
+    /// Creates a <see cref="KernelFunctionMetadata"/> enumeration for a method, specified via an <see cref="MethodInfo"/> instance.
+    /// </summary>
+    /// <param name="instanceType">Specifies the type of the object to extract <see cref="KernelFunctionMetadata"/> for.</param>
+    /// <param name="loggerFactory">The <see cref="ILoggerFactory"/> to use for logging. If null, no logging will be performed.</param>
+    /// <returns>A <see cref="KernelPlugin"/> containing <see cref="KernelFunction"/>s for all relevant members of <paramref name="instanceType"/>.</returns>
+    /// <remarks>
+    /// Methods decorated with <see cref="KernelFunctionAttribute"/> will be included in the plugin.
+    /// Attributed methods must all have different names; overloads are not supported.
+    /// </remarks>
+    public static IEnumerable<KernelFunctionMetadata> CreateFromType(Type instanceType, ILoggerFactory? loggerFactory = null)
+    {
+        Verify.NotNull(instanceType);
+
+        MethodInfo[] methods = instanceType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
+
+        // Filter out non-KernelFunctions and fail if two functions have the same name (with or without the same casing).
+        var functionMetadata = new List<KernelFunctionMetadata>();
+        KernelFunctionFromMethodOptions options = new();
+        foreach (MethodInfo method in methods)
+        {
+            if (method.GetCustomAttribute<KernelFunctionAttribute>() is not null)
+            {
+                functionMetadata.Add(KernelFunctionFromMethod.CreateMetadata(method, loggerFactory: loggerFactory));
+            }
+        }
+        if (functionMetadata.Count == 0)
+        {
+            throw new ArgumentException($"The {instanceType} instance doesn't implement any [KernelFunction]-attributed methods.");
+        }
+
+        return functionMetadata;
+    }
+}

dotnet/src/SemanticKernel.Core/Functions/KernelPluginFactory.cs

@@ -3,6 +3,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Text;
 using System.Text.RegularExpressions;
@@ -36,6 +37,29 @@ public static KernelPlugin CreateFromType<T>(string? pluginName = null, IService
         return CreateFromObject(ActivatorUtilities.CreateInstance<T>(serviceProvider)!, pluginName, serviceProvider?.GetService<ILoggerFactory>());
     }
 
+    /// <summary>Creates a plugin that wraps a new instance of the specified type <paramref name="instanceType"/>.</summary>
+    /// <param name="instanceType">
+    /// Specifies the type of the object to wrap.
+    /// </param>
+    /// <param name="pluginName">
+    /// Name of the plugin for function collection and prompt templates. If the value is null, a plugin name is derived from the <paramref name="instanceType"/>.
+    /// </param>
+    /// <param name="serviceProvider">
+    /// The <see cref="IServiceProvider"/> to use for resolving any required services, such as an <see cref="ILoggerFactory"/>
+    /// and any services required to satisfy a constructor on <paramref name="instanceType"/>.
+    /// </param>
+    /// <returns>A <see cref="KernelPlugin"/> containing <see cref="KernelFunction"/>s for all relevant members of <paramref name="instanceType"/>.</returns>
+    /// <remarks>
+    /// Methods decorated with <see cref="KernelFunctionAttribute"/> will be included in the plugin.
+    /// Attributed methods must all have different names; overloads are not supported.
+    /// </remarks>
+    [Experimental("SKEXP0001")]
+    public static KernelPlugin CreateFromType(Type instanceType, string? pluginName = null, IServiceProvider? serviceProvider = null)
+    {
+        serviceProvider ??= EmptyServiceProvider.Instance;
+        return CreateFromObject(ActivatorUtilities.CreateInstance(serviceProvider, instanceType)!, pluginName, serviceProvider?.GetService<ILoggerFactory>());
+    }
+
     /// <summary>Creates a plugin that wraps the specified target object.</summary>
     /// <param name="target">The instance of the class to be wrapped.</param>
     /// <param name="pluginName">

dotnet/src/SemanticKernel.UnitTests/Functions/KernelFunctionMetadataFactoryTests.cs

@@ -0,0 +1,53 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.ComponentModel;
+using System.Linq;
+using Microsoft.SemanticKernel;
+using Xunit;
+
+namespace SemanticKernel.UnitTests.Functions;
+
+public class KernelFunctionMetadataFactoryTests
+{
+    [Fact]
+    public void ItCanCreateFromType()
+    {
+        // Arrange
+        var instanceType = typeof(MyKernelFunctions);
+
+        // Act
+        var functionMetadata = KernelFunctionMetadataFactory.CreateFromType(instanceType);
+
+        // Assert
+        Assert.NotNull(functionMetadata);
+        Assert.Equal(3, functionMetadata.Count<KernelFunctionMetadata>());
+        Assert.Contains(functionMetadata, f => f.Name == "Function1");
+        Assert.Contains(functionMetadata, f => f.Name == "Function2");
+        Assert.Contains(functionMetadata, f => f.Name == "Function3");
+    }
+
+    #region private
+#pragma warning disable CA1812 // Used in test case above
+    private sealed class MyKernelFunctions
+    {
+        // Disallow instantiation of this class.
+        private MyKernelFunctions()
+        {
+        }
+
+        [KernelFunction("Function1")]
+        [Description("Description for function 1.")]
+        public string Function1([Description("Description for parameter 1")] string param1) => $"Function1: {param1}";
+
+        [KernelFunction("Function2")]
+        [Description("Description for function 2.")]
+        public string Function2([Description("Description for parameter 1")] string param1) => $"Function2: {param1}";
+
+        [KernelFunction("Function3")]
+        [Description("Description for function 3.")]
+        public string Function3([Description("Description for parameter 1")] string param1) => $"Function3: {param1}";
+    }
+#pragma warning restore CA1812
+    #endregion
+}

dotnet/src/SemanticKernel.UnitTests/Functions/KernelPluginFactoryTests.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.ComponentModel;
+using System.Threading.Tasks;
+using Microsoft.SemanticKernel;
+using Xunit;
+
+namespace SemanticKernel.UnitTests.Functions;
+public class KernelPluginFactoryTests
+{
+    [Fact]
+    public async Task ItCanCreateFromObjectAsync()
+    {
+        // Arrange
+        var kernel = new Kernel();
+        var args = new KernelArguments { { "param1", "value1" } };
+        var target = new MyKernelFunctions();
+
+        // Act
+        var plugin = KernelPluginFactory.CreateFromObject(target);
+        FunctionResult result = await plugin["Function1"].InvokeAsync(kernel, args);
+
+        // Assert
+        Assert.NotNull(plugin);
+        Assert.Equal(3, plugin.FunctionCount);
+        Assert.Equal("Function1: value1", result.Value);
+    }
+
+    [Fact]
+    public async Task ItCanCreateFromTypeUsingGenericsAsync()
+    {
+        // Arrange
+        var kernel = new Kernel();
+        var args = new KernelArguments { { "param1", "value1" } };
+
+        // Act
+        var plugin = KernelPluginFactory.CreateFromType<MyKernelFunctions>();
+        FunctionResult result = await plugin["Function1"].InvokeAsync(kernel, args);
+
+        // Assert
+        Assert.NotNull(plugin);
+        Assert.Equal(3, plugin.FunctionCount);
+        Assert.Equal("Function1: value1", result.Value);
+    }
+
+    [Fact]
+    public async Task ItCanCreateFromTypeAsync()
+    {
+        // Arrange
+        var kernel = new Kernel();
+        var args = new KernelArguments { { "param1", "value1" } };
+        var instanceType = typeof(MyKernelFunctions);
+
+        // Act
+        var plugin = KernelPluginFactory.CreateFromType(instanceType);
+        FunctionResult result = await plugin["Function1"].InvokeAsync(kernel, args);
+
+        // Assert
+        Assert.NotNull(plugin);
+        Assert.Equal(3, plugin.FunctionCount);
+        Assert.Equal("Function1: value1", result.Value);
+    }
+
+    #region private
+    private sealed class MyKernelFunctions
+    {
+        [KernelFunction("Function1")]
+        [Description("Description for function 1.")]
+        public string Function1([Description("Description for parameter 1")] string param1) => $"Function1: {param1}";
+
+        [KernelFunction("Function2")]
+        [Description("Description for function 2.")]
+        public string Function2([Description("Description for parameter 1")] string param1) => $"Function2: {param1}";
+
+        [KernelFunction("Function3")]
+        [Description("Description for function 3.")]
+        public string Function3([Description("Description for parameter 1")] string param1) => $"Function3: {param1}";
+    }
+    #endregion
+}