Build a Smart Private Chatbot with Semantic Kernel and APIs

Introduction

This article integrates Semantic Kernel (SK), Ollama, and Qdrant to build a local retrieval-augmented generation (RAG) system with function-calling capabilities. The system is enhanced with custom plugins, including a LocalDateTimePlugin and a WeatherPlugin, allowing it to answer queries beyond basic conversation, such as providing current local time and weather information. This article explains the architecture, tech stack, setup instructions, and a detailed code walkthrough.

Architecture Diagram

Tech Stack Summary

• Semantic Kernel: Microsoft Semantic Kernel enables the integration of language models with external tools and plugins, allowing advanced interactions like embeddings, memory search, and plugin-based function calling.
• Ollama: Ollama is used for generating text embeddings that are vector representations of text. These embeddings are critical for tasks like semantic search and information retrieval.
• Qdrant: Qdrant is a vector database that stores embeddings generated by Ollama. It enables fast similarity search, which is essential for retrieving contextually relevant information based on user input.

Setup Instructions
 

Setting up Ollama

Download the Ollama software from the following URL https://ollama.com/download and follow the instructions to download and run the model locally.

ollama pull llama3.1
ollama pull snowflake-arctic-embed

Setting up Qdrant Using Docker

Download and Install the Docker Desktop from the official website.

1. Pull the Qdrant Docker image.

   docker pull qdrant/qdrant

2. Run Qdrant with Docker.

   docker run -p 6333:6333 qdrant/qdrant

3. Verify if Qdrant is running: http://localhost:6333/dashboard

Code Walkthrough

Configuration Setup

var config = new ConfigurationBuilder()
    .AddUserSecrets(Assembly.GetExecutingAssembly(), true)
    .Build();

This section loads secret keys and model configurations required to run the assistant.

{
  "baseUrl": "",
  "baseEmbeddingUrl": "",
  "qdrantMemoryStoreUrl": "",
  "weatherApiKey": "",
  "modelId": "llama3.1:latest",
  "embeddingModelId": "snowflake-arctic-embed",
  "domainName": "Solar System",
  "domainGuide": "Assets/solar_system.pdf"
}

Replace "baseUrl" and "baseEmbeddingUrl" with the Ollama base URL, "qdrantMemoryStoreUrl" with your quadrant server URL, and "weatherApiKey" with your API keys from weatherapi.com.

Memory Setup

var memory = new MemoryBuilder()
    .WithOllamaTextEmbeddingGeneration(embeddingModelId, 
    new Uri(baseEmbeddingUrl!))
    .WithQdrantMemoryStore(httpClient, 1024, qdrantMemoryStoreUrl)
    .WithHttpClient(httpClient)
    .Build();`

This creates a memory builder using Ollama for text embeddings and Qdrant to store them.

Kernel Initialization

var builder = Kernel.CreateBuilder()
    .AddOpenAIChatCompletion(modelId: modelId, apiKey: null, 
    endpoint: new Uri(baseUrl), httpClient: httpClient);
var kernel = builder.Build();

The kernel integrates the OpenAI chat completion interface for generating chat responses and manages plugin execution for custom functionalities.

Host Instructions

In the context of the Semantic Kernel, prompt instructions serve as a guiding light for the LLM, influencing its decision-making process when choosing the appropriate plugin to execute.

Well-crafted prompt instructions have a profound impact on the LLM's ability to choose the correct plugin and deliver accurate results.

They bridge the gap between human intent and machine understanding, enabling seamless function calling and a more natural user experience. So, always ensure clear, specific, and comprehensive prompt instructions to unlock the full potential of your LLM.

string HostInstructions = $@"You are an Assistant to search content from the {domainName} guide to help users answer their questions.

You can answer general questions like greetings or goodbyes with your response without using any plugins. For all other questions, use the list of available plugins below to get the answer.

List of Available Plugins:
    Local Time Plugin: Retrieve the current date and time.
    Weather Plugin: Calculate the weather for the given location.
    Memory Plugin: Search answers from memory for questions related to {domainName}.

If any of the plugins cannot be used for the given query, even if you know the answer, you should not provide the answer outside of the {domainName} context. Respond with ""I don't have the answer for your question"" and be precise with the response. Do not mention which plugin was used to obtain the answers.
";

Agent and Plugins Setup

ChatCompletionAgent agent = new()
{
    Instructions = HostInstructions,
    Name = HostName,
    Kernel = kernel,
    Arguments = new(settings),
};
var memoryPlugin = new TextMemoryPlugin(memory);
agent.Kernel.ImportPluginFromObject(memoryPlugin);

KernelPlugin localDateTimePlugin = KernelPluginFactory.CreateFromType<LocalDateTimePlugin>();
agent.Kernel.Plugins.Add(localDateTimePlugin);

KernelPlugin weatherPlugin = KernelPluginFactory.CreateFromObject(new WeatherPlugin(weatherApiKey!));
agent.Kernel.Plugins.Add(weatherPlugin);

Here, the ChatCompletionAgent is initialized with specific instructions. Plugins such as TextMemoryPlugin, LocalDateTimePlugin, and WeatherPlugin are registered to extend the assistant's functionality.

Initialize Chat Loop

while (true)
{
    Console.Write("User: ");
    string question = Console.ReadLine()!;
    await InvokeAgentAsync(question);
}

This loop continuously prompts the user for input and invokes the agent to process the queries using memory and plugins.

Embedding Data

async Task EmbedData()
{
    FileContent content = new(MimeTypes.PlainText);
    var pdfDecoder = new PdfDecoder();
    content = await pdfDecoder.DecodeAsync(domainGuide);

    int pageIndex = 1;
    foreach (FileSection section in content.Sections)
    {
        await memory.SaveInformationAsync(domainName, id: $"page{pageIndex}", text: section.Content);
        pageIndex++;
    }
}

The function uses the PDF Loader from the Kernel Memory Library and passes every page content to the Ollama embedding API to embed the data and store it into the Qdrant vector database for later retrieval.

LocalDateTimePlugin

public sealed class LocalDateTimePlugin
{
    [KernelFunction, Description("Retrieves the current date and time in Local Time.")]
    public static String GetCurrentLocalDateTime()
    {
        return DateTime.Now.ToLocalTime().ToString();
    }
}

This plugin retrieves the current local time and can be invoked by the assistant to answer time-related queries.

WeatherPlugin

public sealed class WeatherPlugin(string apiKey)
{
    HttpClient client = new HttpClient();

    [KernelFunction, Description("Gets the weather details of a given location")]
    public async Task<string> GetWeatherAsync(string locationName)
    {
        string url = $"http://api.weatherapi.com/v1/current.json?key={apiKey}&q={locationName}&aqi=no";
        HttpResponseMessage response = await client.GetAsync(url);
        response.EnsureSuccessStatusCode();
        string responseBody = await response.Content.ReadAsStringAsync();
        return responseBody;
    }
}

The WeatherPlugin interacts with an external API to fetch weather details for a given location. The user can ask the assistant about the weather, and it will utilize this plugin.

Ollama TextEmbedding Generation

public class OllamaTextEmbeddingGeneration : ITextEmbeddingGenerationService
{
    public async Task<IList<ReadOnlyMemory<float>>> GenerateEmbeddingsAsync(IList<string> data, Kernel? kernel = null,
        CancellationToken cancellationToken = new())
    {
        var result = new List<ReadOnlyMemory<float>>(data.Count);
        foreach (var text in data)
        {
            var request = new { model = Attributes["model_id"], prompt = text };
            var response = await httpClient.PostAsJsonAsync($"{Attributes["base_url"]}api/embeddings", request, cancellationToken);
            var json = JsonSerializer.Deserialize<JsonNode>(await response.Content.ReadAsStringAsync());
            var embedding = new ReadOnlyMemory<float>(json!["embedding"]?.AsArray().GetValues<float>().ToArray());
            result.Add(embedding);
        }
        return result;
    }
}

This service generates embeddings for input text using Ollama and stores the embeddings in Qdrant for efficient search and retrieval.

Memory Builder Extensions

public static class OllamaMemoryBuilderExtensions
{
    public static MemoryBuilder WithOllamaTextEmbeddingGeneration(this MemoryBuilder builder, string modelId, Uri baseUrl)
    {
        builder.WithTextEmbeddingGeneration((logger, httpclient) => new OllamaTextEmbeddingGeneration(modelId, baseUrl.AbsoluteUri, httpclient, logger));
        return builder;
    }
}

This extension method simplifies the integration of Ollama into the memory-building process.

Final Output

This article demonstrates the power of combining local LLM function calling and RAG with the Semantic Kernel framework. By leveraging Ollama for embeddings and Qdrant for efficient vector storage, you can create a chatbot that understands your domain-specific knowledge and interacts with external services. The ability to run LLMs locally enhances data privacy and control, making it a compelling solution for various enterprise applications. The entire source code is available here in the following GitHub URL.

https://github.com/vavjeeva/SKOllamaLocalRAGSearchWithFunctionCalling

Disclaimer: Please note that the code is based on the current version of the Semantic Kernel. Future updates to the framework may introduce changes that could impact the compatibility or functionality of this code. It's always recommended to refer to the official Semantic Kernel documentation and stay updated with the latest releases.