.Net: Add a request index to the streamed function call update content (#10129)

### Motivation and Context: 
Today, it's impossible to determine which request a streaming function
call update belongs to or originates from. As a result, if an AI service
interaction leads to multiple requests to an AI model - let's say one
per function call - it's impossible to assemble the function call
contents from the streamed updates. This is because the streaming
function call updates from the second request override those from the
first one.

### Description
This PR adds the `RequestIndex` to the
`StreamingFunctionCallUpdateContent` class and updates the {Azure}OpenAI
connectors to set it. Finally, it updates the
`FunctionCallContentBuilder` class to construct a composite index from
`RequestIndex` and `FunctionCallIndex` and uses it to uniquely identify
the function call content updates across requests.

Closes: #10006

Author: SergeyMenshykh

dotnet/samples/Concepts/FunctionCalling/FunctionCalling.cs

@@ -72,7 +72,7 @@ public async Task RunPromptWithAutoFunctionChoiceBehaviorAdvertisingAllKernelFun
 
         OpenAIPromptExecutionSettings settings = new() { FunctionChoiceBehavior = FunctionChoiceBehavior.Auto() };
 
-        Console.WriteLine(await kernel.InvokePromptAsync("Given the current time of day and weather, what is the likely color of the sky in Boston?", new(settings)));
+        Console.WriteLine(await kernel.InvokePromptAsync("What is the likely color of the sky in Boston today?", new(settings)));
 
         // Expected output: "Boston is currently experiencing a rainy day, hence, the likely color of the sky in Boston is grey."
     }
@@ -104,7 +104,7 @@ public async Task RunPromptWithNoneFunctionChoiceBehaviorAdvertisingAllKernelFun
 
         OpenAIPromptExecutionSettings settings = new() { FunctionChoiceBehavior = FunctionChoiceBehavior.None() };
 
-        Console.WriteLine(await kernel.InvokePromptAsync("Tell me which provided functions I would need to call to get the color of the sky in Boston on a specified date.", new(settings)));
+        Console.WriteLine(await kernel.InvokePromptAsync("Tell me which provided functions I would need to call to get the color of the sky in Boston for today.", new(settings)));
 
         // Expected output: "You would first call the `HelperFunctions-GetCurrentUtcDateTime` function to get the current date time in UTC. Then, you would use the `HelperFunctions-GetWeatherForCity` function,
         //                   passing in the city name as 'Boston' and the retrieved UTC date time. Note, however, that these functions won't directly tell you the color of the sky.
@@ -122,7 +122,7 @@ public async Task RunPromptTemplateConfigWithAutoFunctionChoiceBehaviorAdvertisi
         // The `function_choice_behavior.functions` property is omitted which is equivalent to providing all kernel functions to the AI model.
         string promptTemplateConfig = """
             template_format: semantic-kernel
-            template: Given the current time of day and weather, what is the likely color of the sky in Boston?
+            template: What is the likely color of the sky in Boston today?
             execution_settings:
               default:
                 function_choice_behavior:
@@ -177,7 +177,7 @@ public async Task RunNonStreamingChatCompletionApiWithAutomaticFunctionInvocatio
         IChatCompletionService chatCompletionService = kernel.GetRequiredService<IChatCompletionService>();
 
         ChatMessageContent result = await chatCompletionService.GetChatMessageContentAsync(
-            "Given the current time of day and weather, what is the likely color of the sky in Boston?",
+            "What is the likely color of the sky in Boston today?",
             settings,
             kernel);
 
@@ -204,7 +204,7 @@ public async Task RunStreamingChatCompletionApiWithAutomaticFunctionInvocationAs
 
         // Act
         await foreach (var update in chatCompletionService.GetStreamingChatMessageContentsAsync(
-            "Given the current time of day and weather, what is the likely color of the sky in Boston?",
+            "What is the likely color of the sky in Boston today?",
             settings,
             kernel))
         {
@@ -231,7 +231,7 @@ public async Task RunNonStreamingChatCompletionApiWithManualFunctionInvocationAs
         OpenAIPromptExecutionSettings settings = new() { FunctionChoiceBehavior = Microsoft.SemanticKernel.FunctionChoiceBehavior.Auto(autoInvoke: false) };
 
         ChatHistory chatHistory = [];
-        chatHistory.AddUserMessage("Given the current time of day and weather, what is the likely color of the sky in Boston?");
+        chatHistory.AddUserMessage("What is the likely color of the sky in Boston today?");
 
         while (true)
         {
@@ -293,7 +293,7 @@ public async Task RunStreamingChatCompletionApiWithManualFunctionCallingAsync()
 
         // Create chat history with the initial user message
         ChatHistory chatHistory = [];
-        chatHistory.AddUserMessage("Given the current time of day and weather, what is the likely color of the sky in Boston?");
+        chatHistory.AddUserMessage("What is the likely color of the sky in Boston today?");
 
         while (true)
         {
@@ -360,7 +360,7 @@ public async Task RunNonStreamingPromptWithSimulatedFunctionAsync()
         OpenAIPromptExecutionSettings settings = new() { FunctionChoiceBehavior = Microsoft.SemanticKernel.FunctionChoiceBehavior.Auto(autoInvoke: false) };
 
         ChatHistory chatHistory = [];
-        chatHistory.AddUserMessage("Given the current time of day and weather, what is the likely color of the sky in Boston?");
+        chatHistory.AddUserMessage("What is the likely color of the sky in Boston today?");
 
         while (true)
         {
@@ -411,7 +411,7 @@ public async Task DisableFunctionCallingAsync()
         // Alternatively, either omit assigning anything to the `FunctionChoiceBehavior` property or assign null to it to also disable function calling.  
         OpenAIPromptExecutionSettings settings = new() { FunctionChoiceBehavior = FunctionChoiceBehavior.Auto(functions: []) };
 
-        Console.WriteLine(await kernel.InvokePromptAsync("Given the current time of day and weather, what is the likely color of the sky in Boston?", new(settings)));
+        Console.WriteLine(await kernel.InvokePromptAsync("What is the likely color of the sky in Boston today?", new(settings)));
 
         // Expected output: "Sorry, I cannot answer this question as it requires real-time information which I, as a text-based model, cannot access."
     }
@@ -538,8 +538,8 @@ private static Kernel CreateKernel()
         kernel.ImportPluginFromFunctions("HelperFunctions",
         [
             kernel.CreateFunctionFromMethod(() => new List<string> { "Squirrel Steals Show", "Dog Wins Lottery" }, "GetLatestNewsTitles", "Retrieves latest news titles."),
-            kernel.CreateFunctionFromMethod(() => DateTime.UtcNow.ToString("R"), "GetCurrentUtcDateTime", "Retrieves the current date time in UTC."),
-            kernel.CreateFunctionFromMethod((string cityName, string currentDateTime) =>
+            kernel.CreateFunctionFromMethod(() => DateTime.UtcNow.ToString("R"), "GetCurrentDateTimeInUtc", "Retrieves the current date time in UTC."),
+            kernel.CreateFunctionFromMethod((string cityName, string currentDateTimeInUtc) =>
                 cityName switch
                 {
                     "Boston" => "61 and rainy",
@@ -550,7 +550,7 @@ private static Kernel CreateKernel()
                     "Sydney" => "75 and sunny",
                     "Tel Aviv" => "80 and sunny",
                     _ => "31 and snowing",
-                }, "GetWeatherForCity", "Gets the current weather for the specified city"),
+                }, "GetWeatherForCity", "Gets the current weather for the specified city and specified date time."),
         ]);
 
         return kernel;

dotnet/src/Connectors/Connectors.OpenAI/Core/ClientCore.ChatCompletion.cs

@@ -332,7 +332,10 @@ internal async IAsyncEnumerable<OpenAIStreamingChatMessageContent> GetStreamingC
                                     callId: functionCallUpdate.ToolCallId,
                                     name: functionCallUpdate.FunctionName,
                                     arguments: streamingArguments,
-                                    functionCallIndex: functionCallUpdate.Index));
+                                    functionCallIndex: functionCallUpdate.Index)
+                                {
+                                    RequestIndex = requestIndex,
+                                });
                             }
                         }
                         streamedContents?.Add(openAIStreamingChatMessageContent);

dotnet/src/SemanticKernel.Abstractions/Contents/FunctionCallContentBuilder.cs

@@ -15,9 +15,9 @@ namespace Microsoft.SemanticKernel;
 /// </summary>
 public sealed class FunctionCallContentBuilder
 {
-    private Dictionary<int, string>? _functionCallIdsByIndex = null;
-    private Dictionary<int, string>? _functionNamesByIndex = null;
-    private Dictionary<int, StringBuilder>? _functionArgumentBuildersByIndex = null;
+    private Dictionary<string, string>? _functionCallIdsByIndex = null;
+    private Dictionary<string, string>? _functionNamesByIndex = null;
+    private Dictionary<string, StringBuilder>? _functionArgumentBuildersByIndex = null;
     private readonly JsonSerializerOptions? _jsonSerializerOptions;
 
     /// <summary>
@@ -70,7 +70,7 @@ public IReadOnlyList<FunctionCallContent> Build()
 
             for (int i = 0; i < this._functionCallIdsByIndex.Count; i++)
             {
-                KeyValuePair<int, string> functionCallIndexAndId = this._functionCallIdsByIndex.ElementAt(i);
+                KeyValuePair<string, string> functionCallIndexAndId = this._functionCallIdsByIndex.ElementAt(i);
 
                 string? pluginName = null;
                 string functionName = string.Empty;
@@ -96,7 +96,7 @@ public IReadOnlyList<FunctionCallContent> Build()
 
             [UnconditionalSuppressMessage("Trimming", "IL2026:Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code", Justification = "The warning is shown and should be addressed at the class creation site; there is no need to show it again at the function invocation sites.")]
             [UnconditionalSuppressMessage("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "The warning is shown and should be addressed at the class creation site; there is no need to show it again at the function invocation sites.")]
-            (KernelArguments? Arguments, Exception? Exception) GetFunctionArgumentsSafe(int functionCallIndex)
+            (KernelArguments? Arguments, Exception? Exception) GetFunctionArgumentsSafe(string functionCallIndex)
             {
                 if (this._jsonSerializerOptions is not null)
                 {
@@ -118,7 +118,7 @@ public IReadOnlyList<FunctionCallContent> Build()
     /// <returns>A tuple containing the KernelArguments and an Exception if any.</returns>
     [RequiresUnreferencedCode("Uses reflection to deserialize function arguments if no JSOs are provided, making it incompatible with AOT scenarios.")]
     [RequiresDynamicCode("Uses reflection to deserialize function arguments if no JSOs are provided, making it incompatible with AOT scenarios.")]
-    private (KernelArguments? Arguments, Exception? Exception) GetFunctionArguments(int functionCallIndex, JsonSerializerOptions? jsonSerializerOptions = null)
+    private (KernelArguments? Arguments, Exception? Exception) GetFunctionArguments(string functionCallIndex, JsonSerializerOptions? jsonSerializerOptions = null)
     {
         if (this._functionArgumentBuildersByIndex is null ||
             !this._functionArgumentBuildersByIndex.TryGetValue(functionCallIndex, out StringBuilder? functionArgumentsBuilder))
@@ -170,33 +170,36 @@ public IReadOnlyList<FunctionCallContent> Build()
     /// <param name="functionCallIdsByIndex">The dictionary of function call IDs by function call index.</param>
     /// <param name="functionNamesByIndex">The dictionary of function names by function call index.</param>
     /// <param name="functionArgumentBuildersByIndex">The dictionary of function argument builders by function call index.</param>
-    private static void TrackStreamingFunctionCallUpdate(StreamingFunctionCallUpdateContent update, ref Dictionary<int, string>? functionCallIdsByIndex, ref Dictionary<int, string>? functionNamesByIndex, ref Dictionary<int, StringBuilder>? functionArgumentBuildersByIndex)
+    private static void TrackStreamingFunctionCallUpdate(StreamingFunctionCallUpdateContent update, ref Dictionary<string, string>? functionCallIdsByIndex, ref Dictionary<string, string>? functionNamesByIndex, ref Dictionary<string, StringBuilder>? functionArgumentBuildersByIndex)
     {
         if (update is null)
         {
             // Nothing to track.
             return;
         }
 
+        // Create index that is unique across many requests.
+        var functionCallIndex = $"{update.RequestIndex}-{update.FunctionCallIndex}";
+
         // If we have an call id, ensure the index is being tracked. Even if it's not a function update,
         // we want to keep track of it so we can send back an error.
         if (update.CallId is string id && !string.IsNullOrEmpty(id))
         {
-            (functionCallIdsByIndex ??= [])[update.FunctionCallIndex] = id;
+            (functionCallIdsByIndex ??= [])[functionCallIndex] = id;
         }
 
         // Ensure we're tracking the function's name.
         if (update.Name is string name && !string.IsNullOrEmpty(name))
         {
-            (functionNamesByIndex ??= [])[update.FunctionCallIndex] = name;
+            (functionNamesByIndex ??= [])[functionCallIndex] = name;
         }
 
         // Ensure we're tracking the function's arguments.
         if (update.Arguments is string argumentsUpdate)
         {
-            if (!(functionArgumentBuildersByIndex ??= []).TryGetValue(update.FunctionCallIndex, out StringBuilder? arguments))
+            if (!(functionArgumentBuildersByIndex ??= []).TryGetValue(functionCallIndex, out StringBuilder? arguments))
             {
-                functionArgumentBuildersByIndex[update.FunctionCallIndex] = arguments = new();
+                functionArgumentBuildersByIndex[functionCallIndex] = arguments = new();
             }
 
             arguments.Append(argumentsUpdate);

dotnet/src/SemanticKernel.Abstractions/Contents/StreamingFunctionCallUpdateContent.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Text;
 
 namespace Microsoft.SemanticKernel;
@@ -29,6 +30,12 @@ public class StreamingFunctionCallUpdateContent : StreamingKernelContent
     /// </summary>
     public int FunctionCallIndex { get; init; }
 
+    /// <summary>
+    /// Index of the request that produced this message content.
+    /// </summary>
+    [Experimental("SKEXP0001")]
+    public int RequestIndex { get; init; } = 0;
+
     /// <summary>
     /// Creates a new instance of the <see cref="StreamingFunctionCallUpdateContent"/> class.
     /// </summary>

dotnet/src/SemanticKernel.UnitTests/Contents/FunctionCallBuilder/FunctionCallContentBuilderTests.cs

@@ -130,6 +130,58 @@ public void ItShouldBuildFunctionCallContentForManyFunctions(JsonSerializerOptio
         Assert.Null(functionCall2.Exception);
     }
 
+    [Theory]
+    [ClassData(typeof(TestJsonSerializerOptionsForKernelArguments))]
+    public void ItShouldBuildFunctionCallContentForManyFunctionsCameInDifferentRequests(JsonSerializerOptions? jsos)
+    {
+        // Arrange
+        var sut = jsos is not null ? new FunctionCallContentBuilder(jsos) : new FunctionCallContentBuilder();
+
+        // Act
+
+        // f1 call was streamed as part of the first request
+        var f1_update1 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 0, callId: "f_1", name: "WeatherUtils-GetTemperature", arguments: null);
+        sut.Append(f1_update1);
+
+        var f1_update2 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 0, callId: null, name: null, arguments: "{\"city\":");
+        sut.Append(f1_update2);
+
+        var f1_update3 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 0, callId: null, name: null, arguments: "\"Seattle\"}");
+        sut.Append(f1_update3);
+
+        // f2 call was streamed as part of the second request
+        var f2_update1 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 1, callId: null, name: "WeatherUtils-GetHumidity", arguments: null);
+        sut.Append(f2_update1);
+
+        var f2_update2 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 1, callId: "f_2", name: null, arguments: null);
+        sut.Append(f2_update2);
+
+        var f2_update3 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 1, callId: null, name: null, arguments: "{\"city\":");
+        sut.Append(f2_update3);
+
+        var f2_update4 = CreateStreamingContentWithFunctionCallUpdate(choiceIndex: 0, functionCallIndex: 0, requestIndex: 1, callId: null, name: null, arguments: "\"Georgia\"}");
+        sut.Append(f2_update4);
+
+        var functionCalls = sut.Build();
+
+        // Assert
+        Assert.Equal(2, functionCalls.Count);
+
+        var functionCall1 = functionCalls.ElementAt(0);
+        Assert.Equal("f_1", functionCall1.Id);
+        Assert.Equal("WeatherUtils", functionCall1.PluginName);
+        Assert.Equal("GetTemperature", functionCall1.FunctionName);
+        Assert.Equal("Seattle", functionCall1.Arguments?["city"]);
+        Assert.Null(functionCall1.Exception);
+
+        var functionCall2 = functionCalls.ElementAt(1);
+        Assert.Equal("f_2", functionCall2.Id);
+        Assert.Equal("WeatherUtils", functionCall2.PluginName);
+        Assert.Equal("GetHumidity", functionCall2.FunctionName);
+        Assert.Equal("Georgia", functionCall2.Arguments?["city"]);
+        Assert.Null(functionCall2.Exception);
+    }
+
     [Theory]
     [ClassData(typeof(TestJsonSerializerOptionsForKernelArguments))]
     public void ItShouldCaptureArgumentsDeserializationException(JsonSerializerOptions? jsos)
@@ -160,7 +212,7 @@ public void ItShouldCaptureArgumentsDeserializationException(JsonSerializerOptio
         Assert.NotNull(functionCall.Exception);
     }
 
-    private static StreamingChatMessageContent CreateStreamingContentWithFunctionCallUpdate(int choiceIndex, int functionCallIndex, string? callId, string? name, string? arguments)
+    private static StreamingChatMessageContent CreateStreamingContentWithFunctionCallUpdate(int choiceIndex, int functionCallIndex, string? callId, string? name, string? arguments, int requestIndex = 0)
     {
         var content = new StreamingChatMessageContent(AuthorRole.Assistant, null);
 
@@ -171,6 +223,7 @@ private static StreamingChatMessageContent CreateStreamingContentWithFunctionCal
             CallId = callId,
             Name = name,
             Arguments = arguments,
+            RequestIndex = requestIndex
         });
 
         return content;