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Use modelos de IA personalizados e locais com o SDK do Kernel Semântico

Este artigo demonstra como integrar modelos personalizados e locais no SDK do kernel semântico e usá-los para geração de texto e conclusão de bate-papo.

Você pode adaptar as etapas para usá-los com qualquer modelo que você possa acessar, independentemente de onde ou como você acessá-lo. Por exemplo, você pode integrar o modelo codellama com o SDK do kernel semântico para permitir a geração e discussão de código.

Modelos personalizados e locais geralmente fornecem acesso por meio de APIs REST, por exemplo, consulte Compatibilidade com Ollama OpenAI. Antes de integrar seu modelo, ele precisará ser hospedado e acessível ao seu aplicativo .NET via HTTPS.

Pré-requisitos

Implementar a geração de texto usando um modelo local

A seção a seguir mostra como você pode integrar seu modelo com o SDK do kernel semântico e, em seguida, usá-lo para gerar completações de texto.

  1. Crie uma classe de serviço que implemente a ITextGenerationService interface. Por exemplo:

    class MyTextGenerationService : ITextGenerationService
    {
        private IReadOnlyDictionary<string, object?>? _attributes;
        public IReadOnlyDictionary<string, object?> Attributes =>
            _attributes ??= new Dictionary<string, object?>();
    
        public string ModelUrl { get; init; } = "<default url to your model's Chat API>";
        public required string ModelApiKey { get; init; }
    
        public async IAsyncEnumerable<StreamingTextContent> GetStreamingTextContentsAsync(
            string prompt,
            PromptExecutionSettings? executionSettings = null,
            Kernel? kernel = null,
            [EnumeratorCancellation] CancellationToken cancellationToken = default
        )
        {
            // Build your model's request object, specify that streaming is requested
            MyModelRequest request = MyModelRequest.FromPrompt(prompt, executionSettings);
            request.Stream = true;
    
            // Send the completion request via HTTP
            using var httpClient = new HttpClient();
    
            // Send a POST to your model with the serialized request in the body
            using HttpResponseMessage httpResponse = await httpClient.PostAsJsonAsync(
                ModelUrl,
                request,
                cancellationToken
            );
    
            // Verify the request was completed successfully
            httpResponse.EnsureSuccessStatusCode();
    
            // Read your models response as a stream
            using StreamReader reader =
                new(await httpResponse.Content.ReadAsStreamAsync(cancellationToken));
    
            // Iteratively read a chunk of the response until the end of the stream
            // It is more efficient to use a buffer that is the same size as the internal buffer of the stream
            // If the size of the internal buffer was unspecified when the stream was constructed, its default size is 4 kilobytes (2048 UTF-16 characters)
            char[] buffer = new char[2048];
            while (!reader.EndOfStream)
            {
                // Check the cancellation token with each iteration
                cancellationToken.ThrowIfCancellationRequested();
    
                // Fill the buffer with the next set of characters, track how many characters were read
                int readCount = reader.Read(buffer, 0, buffer.Length);
    
                // Convert the character buffer to a string, only include as many characters as were just read
                string chunk = new(buffer, 0, readCount);
    
                yield return new StreamingTextContent(chunk);
            }
        }
    
        public async Task<IReadOnlyList<TextContent>> GetTextContentsAsync(
            string prompt,
            PromptExecutionSettings? executionSettings = null,
            Kernel? kernel = null,
            CancellationToken cancellationToken = default
        )
        {
            // Build your model's request object
            MyModelRequest request = MyModelRequest.FromPrompt(prompt, executionSettings);
    
            // Send the completion request via HTTP
            using var httpClient = new HttpClient();
    
            // Send a POST to your model with the serialized request in the body
            using HttpResponseMessage httpResponse = await httpClient.PostAsJsonAsync(
                ModelUrl,
                request,
                cancellationToken
            );
    
            // Verify the request was completed successfully
            httpResponse.EnsureSuccessStatusCode();
    
            // Deserialize the response body to your model's response object
            // Handle when the deserialization fails and returns null
            MyModelResponse response =
                await httpResponse.Content.ReadFromJsonAsync<MyModelResponse>(cancellationToken)
                ?? throw new Exception("Failed to deserialize response from model");
    
            // Convert your model's response into a list of ChatMessageContent
            return response
                .Completions.Select<string, TextContent>(completion => new(completion))
                .ToImmutableList();
        }
    }
    
  2. Inclua a nova classe de serviço ao criar o Kernel. Por exemplo:

    IKernelBuilder builder = Kernel.CreateBuilder();
    
    // Add your text generation service as a singleton instance
    builder.Services.AddKeyedSingleton<ITextGenerationService>(
        "myTextService1",
        new MyTextGenerationService
        {
            // Specify any properties specific to your service, such as the url or API key
            ModelUrl = "https://localhost:38748",
            ModelApiKey = "myApiKey"
        }
    );
    
    // Alternatively, add your text generation service as a factory method
    builder.Services.AddKeyedSingleton<ITextGenerationService>(
        "myTextService2",
        (_, _) =>
            new MyTextGenerationService
            {
                // Specify any properties specific to your service, such as the url or API key
                ModelUrl = "https://localhost:38748",
                ModelApiKey = "myApiKey"
            }
    );
    
    // Add any other Kernel services or configurations
    // ...
    Kernel kernel = builder.Build();
    
  3. Envie um prompt de geração de texto para seu modelo diretamente através da Kernel classe de serviço ou usando ela. Por exemplo:

    var executionSettings = new PromptExecutionSettings
    {
        // Add execution settings, such as the ModelID and ExtensionData
        ModelId = "MyModelId",
        ExtensionData = new Dictionary<string, object> { { "MaxTokens", 500 } }
    };
    
    // Send a prompt to your model directly through the Kernel
    // The Kernel response will be null if the model can't be reached
    string prompt = "Please list three services offered by Azure";
    string? response = await kernel.InvokePromptAsync<string>(prompt);
    Console.WriteLine($"Output: {response}");
    
    // Alteratively, send a prompt to your model through the text generation service
    ITextGenerationService textService = kernel.GetRequiredService<ITextGenerationService>();
    TextContent responseContents = await textService.GetTextContentAsync(
        prompt,
        executionSettings
    );
    Console.WriteLine($"Output: {responseContents.Text}");
    

Implementar a conclusão do chat usando um modelo local

A seção a seguir mostra como você pode integrar seu modelo com o SDK do Kernel Semântico e, em seguida, usá-lo para concluir o bate-papo.

  1. Crie uma classe de serviço que implemente a IChatCompletionService interface. Por exemplo:

    class MyChatCompletionService : IChatCompletionService
    {
        private IReadOnlyDictionary<string, object?>? _attributes;
        public IReadOnlyDictionary<string, object?> Attributes =>
            _attributes ??= new Dictionary<string, object?>();
    
        public string ModelUrl { get; init; } = "<default url to your model's Chat API>";
        public required string ModelApiKey { get; init; }
    
        public async Task<IReadOnlyList<ChatMessageContent>> GetChatMessageContentsAsync(
            ChatHistory chatHistory,
            PromptExecutionSettings? executionSettings = null,
            Kernel? kernel = null,
            CancellationToken cancellationToken = default
        )
        {
            // Build your model's request object
            MyModelRequest request = MyModelRequest.FromChatHistory(chatHistory, executionSettings);
    
            // Send the completion request via HTTP
            using var httpClient = new HttpClient();
    
            // Send a POST to your model with the serialized request in the body
            using HttpResponseMessage httpResponse = await httpClient.PostAsJsonAsync(
                ModelUrl,
                request,
                cancellationToken
            );
    
            // Verify the request was completed successfully
            httpResponse.EnsureSuccessStatusCode();
    
            // Deserialize the response body to your model's response object
            // Handle when the deserialization fails and returns null
            MyModelResponse response =
                await httpResponse.Content.ReadFromJsonAsync<MyModelResponse>(cancellationToken)
                ?? throw new Exception("Failed to deserialize response from model");
    
            // Convert your model's response into a list of ChatMessageContent
            return response
                .Completions.Select<string, ChatMessageContent>(completion =>
                    new(AuthorRole.Assistant, completion)
                )
                .ToImmutableList();
        }
    
        public async IAsyncEnumerable<StreamingChatMessageContent> GetStreamingChatMessageContentsAsync(
            ChatHistory chatHistory,
            PromptExecutionSettings? executionSettings = null,
            Kernel? kernel = null,
            [EnumeratorCancellation] CancellationToken cancellationToken = default
        )
        {
            // Build your model's request object, specify that streaming is requested
            MyModelRequest request = MyModelRequest.FromChatHistory(chatHistory, executionSettings);
            request.Stream = true;
    
            // Send the completion request via HTTP
            using var httpClient = new HttpClient();
    
            // Send a POST to your model with the serialized request in the body
            using HttpResponseMessage httpResponse = await httpClient.PostAsJsonAsync(
                ModelUrl,
                request,
                cancellationToken
            );
    
            // Verify the request was completed successfully
            httpResponse.EnsureSuccessStatusCode();
    
            // Read your models response as a stream
            using StreamReader reader =
                new(await httpResponse.Content.ReadAsStreamAsync(cancellationToken));
    
            // Iteratively read a chunk of the response until the end of the stream
            // It is more efficient to use a buffer that is the same size as the internal buffer of the stream
            // If the size of the internal buffer was unspecified when the stream was constructed, its default size is 4 kilobytes (2048 UTF-16 characters)
            char[] buffer = new char[2048];
            while (!reader.EndOfStream)
            {
                // Check the cancellation token with each iteration
                cancellationToken.ThrowIfCancellationRequested();
    
                // Fill the buffer with the next set of characters, track how many characters were read
                int readCount = reader.Read(buffer, 0, buffer.Length);
    
                // Convert the character buffer to a string, only include as many characters as were just read
                string chunk = new(buffer, 0, readCount);
    
                yield return new StreamingChatMessageContent(AuthorRole.Assistant, chunk);
            }
        }
    }
    
  2. Inclua a nova classe de serviço ao criar o Kernel. Por exemplo:

    IKernelBuilder builder = Kernel.CreateBuilder();
    
    // Add your chat completion service as a singleton instance
    builder.Services.AddKeyedSingleton<IChatCompletionService>(
        "myChatService1",
        new MyChatCompletionService
        {
            // Specify any properties specific to your service, such as the url or API key
            ModelUrl = "https://localhost:38748",
            ModelApiKey = "myApiKey"
        }
    );
    
    // Alternatively, add your chat completion service as a factory method
    builder.Services.AddKeyedSingleton<IChatCompletionService>(
        "myChatService2",
        (_, _) =>
            new MyChatCompletionService
            {
                // Specify any properties specific to your service, such as the url or API key
                ModelUrl = "https://localhost:38748",
                ModelApiKey = "myApiKey"
            }
    );
    
    // Add any other Kernel services or configurations
    // ...
    Kernel kernel = builder.Build();
    
  3. Envie um prompt de conclusão de bate-papo para seu modelo diretamente através da Kernel classe de serviço ou usando ela. Por exemplo:

    var executionSettings = new PromptExecutionSettings
    {
        // Add execution settings, such as the ModelID and ExtensionData
        ModelId = "MyModelId",
        ExtensionData = new Dictionary<string, object> { { "MaxTokens", 500 } }
    };
    
    // Send a string representation of the chat history to your model directly through the Kernel
    // This uses a special syntax to denote the role for each message
    // For more information on this syntax see:
    // https://learn.microsoft.com/en-us/semantic-kernel/prompts/your-first-prompt?tabs=Csharp
    string prompt = """
        <message role="system">the initial system message for your chat history</message>
        <message role="user">the user's initial message</message>
        """;
    
    string? response = await kernel.InvokePromptAsync<string>(prompt);
    Console.WriteLine($"Output: {response}");
    
    // Alteratively, send a prompt to your model through the chat completion service
    // First, initialize a chat history with your initial system message
    string systemMessage = "<the initial system message for your chat history>";
    Console.WriteLine($"System Prompt: {systemMessage}");
    var chatHistory = new ChatHistory(systemMessage);
    
    // Add the user's input to your chat history
    string userRequest = "<the user's initial message>";
    Console.WriteLine($"User: {userRequest}");
    chatHistory.AddUserMessage(userRequest);
    
    // Get the models response and add it to the chat history
    IChatCompletionService service = kernel.GetRequiredService<IChatCompletionService>();
    ChatMessageContent responseMessage = await service.GetChatMessageContentAsync(
        chatHistory,
        executionSettings
    );
    Console.WriteLine($"Assistant: {responseMessage.Content}");
    chatHistory.Add(responseMessage);
    
    // Continue sending and receiving messages between the user and model
    // ...