.Net: Introduce IAIServiceSelector interface to allow AI service and …

…request settings to be selected during semantic function execution (#3227)

### Motivation and Context

Fix following issues for Semantic functions:

1. Allow semantic functions to dynamically retrieve the AI service and
request settings to be used when executing the function

Previously semantic functions execution has the following limitations:

1. The AI service was set on the semantic function when it was created.
This meant that an instance of a semantic function could not be used
with multiple different Kernel instances.
1. The AI request settings were set on the semantic function when it was
created. This meant that different request settings could not be
selected when the function was executed.

### Description

This PR add's a new abstraction called `IAIServiceSelector`. An instance
of this is added to a semantic function when it is created. The default
implementation works as follows:

1. If the semantic function only has a single associated model request
setting instance with no service id then the default AI service and the
model request settings are used. This is consistent with the previous
behaviour.
1. If the semantic function only has a single associated model request
setting instance with a service id then the named AI service and the
model request settings are used. If the named AI service is not
available an exception will be thrown. This is consistent with the
previous behaviour.
1. If the semantic function only has multiple associated model request
setting instances then:
    1. The model request setting instances are considered in order
1. The first model request setting instance with no service id is
considered the default
1. For each model request setting instance that has a service id, if the
service exists then it will be used with the associated model request
settings
1. If no matching service can be found and default request settings are
provided the default service will be used
1. If no matching service can be found and no default request settings
are provided an exception will be thrown

### Contribution Checklist

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

dotnet/src/Extensions/Extensions.UnitTests/TemplateEngine/Prompt/Blocks/CodeBlockTests.cs

@@ -10,6 +10,7 @@
 using Microsoft.SemanticKernel.AI;
 using Microsoft.SemanticKernel.Diagnostics;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Microsoft.SemanticKernel.TemplateEngine.Basic.Blocks;
 using Moq;
 using Xunit;
@@ -21,6 +22,7 @@ public class CodeBlockTests
     private readonly Mock<IReadOnlyFunctionCollection> _functions;
     private readonly ILoggerFactory _logger = NullLoggerFactory.Instance;
     private readonly Mock<IFunctionRunner> _functionRunner = new();
+    private readonly Mock<IAIServiceProvider> _serviceProvider = new();
 
     public CodeBlockTests()
     {
@@ -32,7 +34,7 @@ public async Task ItThrowsIfAFunctionDoesntExistAsync()
     {
         // Arrange
         var functionRunner = new Mock<IFunctionRunner>();
-        var context = new SKContext(this._functionRunner.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object);
         var target = new CodeBlock("functionName", this._logger);
 
         this._functionRunner.Setup(r => r.RunAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<ContextVariables>(), It.IsAny<CancellationToken>()))
@@ -49,7 +51,7 @@ public async Task ItThrowsIfAFunctionDoesntExistAsync()
     public async Task ItThrowsIfAFunctionCallThrowsAsync()
     {
         // Arrange
-        var context = new SKContext(this._functionRunner.Object, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, functions: this._functions.Object);
         var function = new Mock<ISKFunction>();
         function
             .Setup(x => x.InvokeAsync(It.IsAny<SKContext>(), It.IsAny<AIRequestSettings?>(), It.IsAny<CancellationToken>()))
@@ -145,7 +147,7 @@ public async Task ItRendersCodeBlockConsistingOfJustAVarBlock1Async()
     {
         // Arrange
         var variables = new ContextVariables { ["varName"] = "foo" };
-        var context = new SKContext(this._functionRunner.Object, variables, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables, functions: this._functions.Object);
 
         // Act
         var codeBlock = new CodeBlock("$varName", NullLoggerFactory.Instance);
@@ -160,7 +162,7 @@ public async Task ItRendersCodeBlockConsistingOfJustAVarBlock2Async()
     {
         // Arrange
         var variables = new ContextVariables { ["varName"] = "bar" };
-        var context = new SKContext(this._functionRunner.Object, variables, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables, functions: this._functions.Object);
         var varBlock = new VarBlock("$varName");
 
         // Act
@@ -175,7 +177,7 @@ public async Task ItRendersCodeBlockConsistingOfJustAVarBlock2Async()
     public async Task ItRendersCodeBlockConsistingOfJustAValBlock1Async()
     {
         // Arrange
-        var context = new SKContext(this._functionRunner.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object);
 
         // Act
         var codeBlock = new CodeBlock("'ciao'", NullLoggerFactory.Instance);
@@ -190,7 +192,7 @@ public async Task ItRendersCodeBlockConsistingOfJustAValBlock2Async()
     {
         // Arrange
         var kernel = new Mock<IKernel>();
-        var context = new SKContext(this._functionRunner.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object);
         var valBlock = new ValBlock("'arrivederci'");
 
         // Act
@@ -209,7 +211,7 @@ public async Task ItInvokesFunctionCloningAllVariablesAsync()
         const string Plugin = "pluginName";
 
         var variables = new ContextVariables { ["input"] = "zero", ["var1"] = "uno", ["var2"] = "due" };
-        var context = new SKContext(this._functionRunner.Object, variables, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables, functions: this._functions.Object);
         var funcId = new FunctionIdBlock(Func);
 
         var canary0 = string.Empty;
@@ -257,7 +259,7 @@ public async Task ItInvokesFunctionWithCustomVariableAsync()
         const string VarValue = "varValue";
 
         var variables = new ContextVariables { [Var] = VarValue };
-        var context = new SKContext(this._functionRunner.Object, variables, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables, functions: this._functions.Object);
         var funcId = new FunctionIdBlock(Func);
         var varBlock = new VarBlock($"${Var}");
 
@@ -290,7 +292,7 @@ public async Task ItInvokesFunctionWithCustomValueAsync()
         const string Plugin = "pluginName";
         const string Value = "value";
 
-        var context = new SKContext(this._functionRunner.Object, variables: null, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables: null, functions: this._functions.Object);
         var funcId = new FunctionIdBlock(Func);
         var valBlock = new ValBlock($"'{Value}'");
 
@@ -328,7 +330,7 @@ public async Task ItInvokesFunctionWithNamedArgsAsync()
         var variables = new ContextVariables();
         variables.Set("bob", BobValue);
         variables.Set("input", Value);
-        var context = new SKContext(this._functionRunner.Object, variables: variables, functions: this._functions.Object);
+        var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables: variables, functions: this._functions.Object);
         var funcId = new FunctionIdBlock(Func);
         var namedArgBlock1 = new NamedArgBlock($"foo='{FooValue}'");
         var namedArgBlock2 = new NamedArgBlock("baz=$bob");
@@ -362,7 +364,7 @@ private void MockFunctionRunner(ISKFunction function)
         this._functionRunner.Setup(r => r.RunAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<ContextVariables>(), It.IsAny<CancellationToken>()))
             .Returns<string, string, ContextVariables, CancellationToken>((pluginName, functionName, variables, cancellationToken) =>
             {
-                var context = new SKContext(this._functionRunner.Object, variables);
+                var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables);
                 return function.InvokeAsync(context, null, cancellationToken);
             });
     }

dotnet/src/Extensions/Extensions.UnitTests/TemplateEngine/Prompt/PromptTemplateEngineTests.cs

@@ -11,6 +11,7 @@
 using Microsoft.SemanticKernel;
 using Microsoft.SemanticKernel.Diagnostics;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Microsoft.SemanticKernel.TemplateEngine.Basic;
 using Microsoft.SemanticKernel.TemplateEngine.Basic.Blocks;
 using Moq;
@@ -29,6 +30,7 @@ public sealed class PromptTemplateEngineTests
     private readonly ITestOutputHelper _logger;
     private readonly Mock<IKernel> _kernel;
     private readonly Mock<IFunctionRunner> _functionRunner;
+    private readonly Mock<IAIServiceProvider> _serviceProvider;
 
     public PromptTemplateEngineTests(ITestOutputHelper testOutputHelper)
     {
@@ -38,6 +40,7 @@ public PromptTemplateEngineTests(ITestOutputHelper testOutputHelper)
         this._functions = new Mock<IReadOnlyFunctionCollection>();
         this._kernel = new Mock<IKernel>();
         this._functionRunner = new Mock<IFunctionRunner>();
+        this._serviceProvider = new Mock<IAIServiceProvider>();
     }
 
     [Fact]
@@ -375,7 +378,7 @@ private void MockFunctionRunner(ISKFunction function)
         this._functionRunner.Setup(r => r.RunAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<ContextVariables>(), It.IsAny<CancellationToken>()))
             .Returns<string, string, ContextVariables, CancellationToken>((pluginName, functionName, variables, cancellationToken) =>
             {
-                var context = new SKContext(this._functionRunner.Object, variables);
+                var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables);
                 return function.InvokeAsync(context, null, cancellationToken);
             });
     }
@@ -385,7 +388,7 @@ private void MockFunctionRunner(List<ISKFunction> functions)
         this._functionRunner.Setup(r => r.RunAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<ContextVariables>(), It.IsAny<CancellationToken>()))
             .Returns<string, string, ContextVariables, CancellationToken>((pluginName, functionName, variables, cancellationToken) =>
             {
-                var context = new SKContext(this._functionRunner.Object, variables);
+                var context = new SKContext(this._functionRunner.Object, this._serviceProvider.Object, variables);
                 var function = functions.First(f => f.PluginName == functionName);
 
                 return function.InvokeAsync(context, null, cancellationToken);
@@ -396,6 +399,7 @@ private SKContext MockContext()
     {
         return new SKContext(
             this._functionRunner.Object,
+            this._serviceProvider.Object,
             this._variables,
             this._functions.Object);
     }

dotnet/src/IntegrationTests/Plugins/SamplePluginsTests.cs

@@ -25,8 +25,6 @@ public void CanLoadSamplePluginsRequestSettings()
         {
             var function = kernel.Functions.GetFunction(view.PluginName, view.Name);
             Assert.NotNull(function);
-            Assert.NotNull(function.RequestSettings);
-            Assert.True(function.RequestSettings.ExtensionData.ContainsKey("max_tokens"));
         });
     }
 
@@ -49,8 +47,6 @@ public void CanLoadSampleSkillsCompletions()
         {
             var function = kernel.Functions.GetFunction(view.PluginName, view.Name);
             Assert.NotNull(function);
-            Assert.NotNull(function.RequestSettings);
-            Assert.True(function.RequestSettings.ExtensionData.ContainsKey("max_tokens"));
         });
     }
 }

dotnet/src/Planners/Planners.Core.UnitTests/Action/ActionPlannerTests.cs

@@ -6,6 +6,7 @@
 using Microsoft.SemanticKernel.AI;
 using Microsoft.SemanticKernel.Diagnostics;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Moq;
 using Xunit;
 
@@ -163,11 +164,12 @@ private Mock<IKernel> CreateMockKernelAndFunctionFlowWithTestString(string testP
             functions.Setup(x => x.GetFunctionViews()).Returns(new List<FunctionView>());
         }
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
         var kernel = new Mock<IKernel>();
 
-        var returnContext = new SKContext(functionRunner.Object, new ContextVariables(testPlanString), functions.Object);
+        var returnContext = new SKContext(functionRunner.Object, serviceProvider.Object, new ContextVariables(testPlanString), functions.Object);
 
-        var context = new SKContext(functionRunner.Object, functions: functions.Object);
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, functions: functions.Object);
 
         var mockFunctionFlowFunction = new Mock<ISKFunction>();
         mockFunctionFlowFunction.Setup(x => x.InvokeAsync(

dotnet/src/Planners/Planners.Core.UnitTests/Extensions/ReadOnlyFunctionCollectionExtensionsTests.cs

@@ -2,6 +2,7 @@
 
 using Microsoft.SemanticKernel.Memory;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Moq;
 using Xunit;
 
@@ -57,9 +58,10 @@ public async Task CanCallGetAvailableFunctionsWithNoFunctionsAsync(Type t)
             .Returns(asyncEnumerable);
 
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
 
         // Arrange GetAvailableFunctionsAsync parameters
-        var context = new SKContext(functionRunner.Object, variables);
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, variables);
         var config = InitializeConfig(t);
         var semanticQuery = "test";
 
@@ -136,9 +138,10 @@ public async Task CanCallGetAvailableFunctionsWithFunctionsAsync(Type t)
         functions.Setup(x => x.GetFunctionViews()).Returns(functionsView);
 
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
 
         // Arrange GetAvailableFunctionsAsync parameters
-        var context = new SKContext(functionRunner.Object, variables, functions.Object);
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, variables, functions.Object);
         var config = InitializeConfig(t);
         var semanticQuery = "test";
 
@@ -206,9 +209,10 @@ public async Task CanCallGetAvailableFunctionsWithFunctionsWithRelevancyAsync(Ty
         functions.Setup(x => x.GetFunctionViews()).Returns(functionsView);
 
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
 
         // Arrange GetAvailableFunctionsAsync parameters
-        var context = new SKContext(functionRunner.Object, variables, functions.Object);
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, variables, functions.Object);
         var config = InitializeConfig(t);
         config.SemanticMemoryConfig = new() { RelevancyThreshold = 0.78, Memory = memory.Object };
         var semanticQuery = "test";
@@ -243,6 +247,7 @@ public async Task CanCallGetAvailableFunctionsAsyncWithDefaultRelevancyAsync(Typ
         // Arrange
         var kernel = new Mock<IKernel>();
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
 
         var variables = new ContextVariables();
         var functions = new FunctionCollection();
@@ -267,7 +272,7 @@ public async Task CanCallGetAvailableFunctionsAsyncWithDefaultRelevancyAsync(Typ
             .Returns(asyncEnumerable);
 
         // Arrange GetAvailableFunctionsAsync parameters
-        var context = new SKContext(functionRunner.Object, variables);
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, variables);
         var config = InitializeConfig(t);
         config.SemanticMemoryConfig = new() { RelevancyThreshold = 0.78, Memory = memory.Object };
         var semanticQuery = "test";

dotnet/src/Planners/Planners.Core.UnitTests/Sequential/SequentialPlanParserTests.cs

@@ -4,6 +4,7 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.SemanticKernel.Diagnostics;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Microsoft.SemanticKernel.TemplateEngine;
 using Moq;
 using Xunit;
@@ -38,9 +39,10 @@ private Mock<IKernel> CreateKernelMock(
 
     private SKContext CreateSKContext(
         IFunctionRunner functionRunner,
+        IAIServiceProvider serviceProvider,
         ContextVariables? variables = null)
     {
-        return new SKContext(functionRunner, variables);
+        return new SKContext(functionRunner, serviceProvider, variables);
     }
 
     private static Mock<ISKFunction> CreateMockFunction(FunctionView functionView, string result = "")
@@ -59,12 +61,13 @@ private void CreateKernelAndFunctionCreateMocks(List<(string name, string plugin
         kernel = kernelMock.Object;
 
         var functionRunnerMock = new Mock<IFunctionRunner>();
+        var serviceProviderMock = new Mock<IAIServiceProvider>();
 
         // For Create
         kernelMock.Setup(k => k.CreateNewContext(It.IsAny<ContextVariables>(), It.IsAny<IReadOnlyFunctionCollection>(), It.IsAny<ILoggerFactory>(), It.IsAny<CultureInfo>()))
             .Returns<ContextVariables, IReadOnlyFunctionCollection, ILoggerFactory, CultureInfo>((contextVariables, skills, loggerFactory, culture) =>
             {
-                return this.CreateSKContext(functionRunnerMock.Object, contextVariables);
+                return this.CreateSKContext(functionRunnerMock.Object, serviceProviderMock.Object, contextVariables);
             });
 
         var functionsView = new List<FunctionView>();
@@ -77,7 +80,7 @@ private void CreateKernelAndFunctionCreateMocks(List<(string name, string plugin
             var mockFunction = CreateMockFunction(functionView);
             functionsView.Add(functionView);
 
-            var result = this.CreateSKContext(functionRunnerMock.Object);
+            var result = this.CreateSKContext(functionRunnerMock.Object, serviceProviderMock.Object);
             result.Variables.Update(resultString);
             mockFunction.Setup(x => x.InvokeAsync(It.IsAny<SKContext>(), null, It.IsAny<CancellationToken>()))
                 .ReturnsAsync(new FunctionResult(name, pluginName, result));
@@ -88,7 +91,8 @@ private void CreateKernelAndFunctionCreateMocks(List<(string name, string plugin
                     It.IsAny<string>(),
                     It.IsAny<string>(),
                     It.IsAny<PromptTemplateConfig>(),
-                    It.IsAny<IPromptTemplate>()
+                    It.IsAny<IPromptTemplate>(),
+                    It.IsAny<IAIServiceSelector>()
                 )).Returns(mockFunction.Object);
             }
             else

dotnet/src/Planners/Planners.Core.UnitTests/Sequential/SequentialPlannerTests.cs

@@ -5,6 +5,7 @@
 using Microsoft.SemanticKernel.AI;
 using Microsoft.SemanticKernel.Diagnostics;
 using Microsoft.SemanticKernel.Orchestration;
+using Microsoft.SemanticKernel.Services;
 using Moq;
 using Xunit;
 
@@ -60,17 +61,20 @@ public async Task ItCanCreatePlanAsync(string goal)
 
         functions.Setup(x => x.GetFunctionViews()).Returns(functionsView);
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
         kernel.Setup(x => x.LoggerFactory).Returns(new Mock<ILoggerFactory>().Object);
 
         var expectedFunctions = input.Select(x => x.name).ToList();
         var expectedPlugins = input.Select(x => x.pluginName).ToList();
 
         var context = new SKContext(
             functionRunner.Object,
+            serviceProvider.Object,
             new ContextVariables());
 
         var returnContext = new SKContext(
             functionRunner.Object,
+            serviceProvider.Object,
             new ContextVariables());
 
         var planString =
@@ -147,15 +151,16 @@ public async Task InvalidXMLThrowsAsync()
     {
         // Arrange
         var functionRunner = new Mock<IFunctionRunner>();
+        var serviceProvider = new Mock<IAIServiceProvider>();
         var kernel = new Mock<IKernel>();
         var functions = new Mock<IFunctionCollection>();
 
         functions.Setup(x => x.GetFunctionViews()).Returns(new List<FunctionView>());
 
         var planString = "<plan>notvalid<</plan>";
-        var returnContext = new SKContext(functionRunner.Object, new ContextVariables(planString));
+        var returnContext = new SKContext(functionRunner.Object, serviceProvider.Object, new ContextVariables(planString));
 
-        var context = new SKContext(functionRunner.Object, new ContextVariables());
+        var context = new SKContext(functionRunner.Object, serviceProvider.Object, new ContextVariables());
 
         var mockFunctionFlowFunction = new Mock<ISKFunction>();
         mockFunctionFlowFunction.Setup(x => x.InvokeAsync(