Big improvements to the Ollama agent (PowerShell#310)

1. Switching to `OllamaSharp` to simplify API calls and support both streaming and non-streaming.
2. Add context support to enable the agent to remember previous responses.
3. Add configuration management support.
4. Improving chat interaction.

Author: kborowinski

shell/agents/AIShell.Ollama.Agent/AIShell.Ollama.Agent.csproj

@@ -4,6 +4,7 @@
     <TargetFramework>net8.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <SuppressNETCoreSdkPreviewMessage>true</SuppressNETCoreSdkPreviewMessage>
+    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
 
     <!-- Disable deps.json generation -->
     <GenerateDependencyFile>false</GenerateDependencyFile>
@@ -15,6 +16,10 @@
     <DebugType>None</DebugType>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="OllamaSharp" Version="4.0.8" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\..\AIShell.Abstraction\AIShell.Abstraction.csproj">
       <!-- Disable copying AIShell.Abstraction.dll to output folder -->

shell/agents/AIShell.Ollama.Agent/OllamaAgent.cs

@@ -1,10 +1,33 @@
 using System.Diagnostics;
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
 using AIShell.Abstraction;
+using OllamaSharp;
+using OllamaSharp.Models;
 
 namespace AIShell.Ollama.Agent;
 
-public sealed class OllamaAgent : ILLMAgent
+public sealed partial class OllamaAgent : ILLMAgent
 {
+    private bool _reloadSettings;
+    private bool _isDisposed;
+    private string _configRoot;
+    private Settings _settings;
+    private OllamaApiClient _client;
+    private GenerateRequest _request;
+    private FileSystemWatcher _watcher;
+
+    /// <summary>
+    /// The name of setting file
+    /// </summary>
+    private const string SettingFileName = "ollama.config.json";
+
+    /// <summary>
+    /// Gets the settings.
+    /// </summary>
+    internal Settings Settings => _settings;
+
     /// <summary>
     /// The name of the agent
     /// </summary>
@@ -13,7 +36,7 @@ public sealed class OllamaAgent : ILLMAgent
     /// <summary>
     /// The description of the agent to be shown at start up
     /// </summary>
-    public string Description => "This is an AI assistant to interact with a language model running locally by utilizing the Ollama CLI tool. Be sure to follow all prerequisites in aka.ms/aish/ollama";
+    public string Description => "This is an AI assistant to interact with a language model running locally or remotely by utilizing the Ollama API. Be sure to follow all prerequisites in https://github.com/PowerShell/AIShell/tree/main/shell/agents/AIShell.Ollama.Agent";
 
     /// <summary>
     /// This is the company added to /like and /dislike verbiage for who the telemetry helps.
@@ -30,19 +53,25 @@ public sealed class OllamaAgent : ILLMAgent
     /// <summary>
     /// These are any optional legal/additional information links you want to provide at start up
     /// </summary>
-    public Dictionary<string, string> LegalLinks { private set; get; }
-
-    /// <summary>
-    /// This is the chat service to call the API from
-    /// </summary>
-    private OllamaChatService _chatService;
+    public Dictionary<string, string> LegalLinks { private set; get; } = new(StringComparer.OrdinalIgnoreCase)
+    {
+        ["Ollama Docs"] = "https://github.com/ollama/ollama",
+        ["Prerequisites"] = "https://github.com/PowerShell/AIShell/tree/main/shell/agents/AIShell.Ollama.Agent"
+    };
 
     /// <summary>
     /// Dispose method to clean up the unmanaged resource of the chatService
     /// </summary>
     public void Dispose()
     {
-        _chatService?.Dispose();
+        if (_isDisposed)
+        {
+            return;
+        }
+
+        GC.SuppressFinalize(this);
+        _watcher.Dispose();
+        _isDisposed = true;
     }
 
     /// <summary>
@@ -51,13 +80,31 @@ public void Dispose()
     /// <param name="config">Agent configuration for any configuration file and other settings</param>
     public void Initialize(AgentConfig config)
     {
-        _chatService = new OllamaChatService();
+        _configRoot = config.ConfigurationRoot;
+
+        SettingFile = Path.Combine(_configRoot, SettingFileName);
+        _settings = ReadSettings();
+
+        if (_settings is null)
+        {
+            // Create the setting file with examples to serve as a template for user to update.
+            NewExampleSettingFile();
+            _settings = ReadSettings();
+        }
+
+        // Create Ollama request
+        _request = new GenerateRequest();
+
+        // Create Ollama client
+        _client = new OllamaApiClient(_settings.Endpoint);
 
-        LegalLinks = new(StringComparer.OrdinalIgnoreCase)
+        // Watch for changes to the settings file
+        _watcher = new FileSystemWatcher(_configRoot, SettingFileName)
         {
-            ["Ollama Docs"] = "https://github.com/ollama/ollama",
-            ["Prerequisites"] = "https://aka.ms/ollama/readme"
+            NotifyFilter = NotifyFilters.LastWrite,
+            EnableRaisingEvents = true,
         };
+        _watcher.Changed += OnSettingFileChange;
     }
 
     /// <summary>
@@ -68,7 +115,7 @@ public void Initialize(AgentConfig config)
     /// <summary>
     /// Gets the path to the setting file of the agent.
     /// </summary>
-    public string SettingFile { private set; get; } = null;
+    public string SettingFile { private set; get; }
 
     /// <summary>
     /// Gets a value indicating whether the agent accepts a specific user action feedback.
@@ -87,7 +134,19 @@ public void OnUserAction(UserActionPayload actionPayload) {}
     /// Refresh the current chat by starting a new chat session.
     /// This method allows an agent to reset chat states, interact with user for authentication, print welcome message, and more.
     /// </summary>
-    public Task RefreshChatAsync(IShell shell, bool force) => Task.CompletedTask;
+    public Task RefreshChatAsync(IShell shell, bool force)
+    {
+        if (force)
+        {
+            // Reload the setting file if needed.
+            ReloadSettings();
+
+            // Reset context
+            _request.Context = null;
+        }
+
+        return Task.CompletedTask;
+    }
 
     /// <summary>
     /// Main chat function that takes the users input and passes it to the LLM and renders it.
@@ -100,26 +159,171 @@ public async Task<bool> ChatAsync(string input, IShell shell)
         // Get the shell host
         IHost host = shell.Host;
 
-        // get the cancellation token
+        // Get the cancellation token
         CancellationToken token = shell.CancellationToken;
 
-        if (Process.GetProcessesByName("ollama").Length is 0)
+        // Reload the setting file if needed.
+        ReloadSettings();
+
+        if (IsLocalHost().IsMatch(_client.Uri.Host) && Process.GetProcessesByName("ollama").Length is 0)
         {
-            host.RenderFullResponse("Please be sure the Ollama is installed and server is running. Check all the prerequisites in the README of this agent are met.");
+            host.WriteErrorLine("Please be sure the Ollama is installed and server is running. Check all the prerequisites in the README of this agent are met.");
             return false;
         }
 
-        ResponseData ollamaResponse = await host.RunWithSpinnerAsync(
-            status: "Thinking ...",
-            func: async context => await _chatService.GetChatResponseAsync(context, input, token)
-        ).ConfigureAwait(false);
+        // Prepare request
+        _request.Prompt = input;
+        _request.Model = _settings.Model;
+        _request.Stream = _settings.Stream;
 
-        if (ollamaResponse is not null)
+        try
         {
-            // render the content
-            host.RenderFullResponse(ollamaResponse.response);
+            if (_request.Stream)
+            {
+                // Wait for the stream with the spinner running
+                var ollamaStreamEnumerator = await host.RunWithSpinnerAsync(
+                    status: "Thinking ...",
+                    func: async () =>
+                    {
+                        // Start generating the stream asynchronously and return an enumerator
+                        var enumerator = _client.GenerateAsync(_request, token).GetAsyncEnumerator(token);
+                        if (await enumerator.MoveNextAsync().ConfigureAwait(false))
+                        {
+                            return enumerator;
+                        }
+                        return null;
+                    }
+                ).ConfigureAwait(false);
+
+                if (ollamaStreamEnumerator is not null)
+                {
+                    using IStreamRender streamingRender = host.NewStreamRender(token);
+
+                    do
+                    {
+                        var currentStream = ollamaStreamEnumerator.Current;
+
+                        // Update the render with stream response
+                        streamingRender.Refresh(currentStream.Response);
+
+                        if (currentStream.Done)
+                        {
+                            // If the stream is complete, update the request context with the last stream context
+                            var ollamaLastStream = (GenerateDoneResponseStream)currentStream;
+                            _request.Context = ollamaLastStream.Context;
+                        }
+                    }
+                    while (await ollamaStreamEnumerator.MoveNextAsync().ConfigureAwait(false));
+                }
+            }
+            else
+            {
+                // Build single response with spinner
+                var ollamaResponse = await host.RunWithSpinnerAsync(
+                    status: "Thinking ...",
+                    func: async () => { return await _client.GenerateAsync(_request, token).StreamToEndAsync(); }
+                ).ConfigureAwait(false);
+
+                // Update request context
+                _request.Context = ollamaResponse.Context;
+
+                // Render the full response
+                host.RenderFullResponse(ollamaResponse.Response);
+            }
         }
-        
+        catch (OperationCanceledException)
+        {
+            // Ignore the cancellation exception.
+        }
+        catch (HttpRequestException e)
+        {
+            host.WriteErrorLine($"{e.Message}");
+            host.WriteErrorLine($"Ollama model:    \"{_settings.Model}\"");
+            host.WriteErrorLine($"Ollama endpoint: \"{_settings.Endpoint}\"");
+            host.WriteErrorLine($"Ollama settings: \"{SettingFile}\"");
+        }
+
         return true;
     }
+
+    private void ReloadSettings()
+    {
+        if (_reloadSettings)
+        {
+            _reloadSettings = false;
+            var settings = ReadSettings();
+            if (settings is null)
+            {
+                return;
+            }
+
+            _settings = settings;
+
+            // Check if the endpoint has changed
+            bool isEndpointChanged = !string.Equals(_settings.Endpoint, _client.Uri.OriginalString, StringComparison.OrdinalIgnoreCase);
+
+            if (isEndpointChanged)
+            {
+                // Create a new client with updated endpoint
+                _client = new OllamaApiClient(_settings.Endpoint);
+            }
+        }
+    }
+
+    private Settings ReadSettings()
+    {
+        Settings settings = null;
+        FileInfo file = new(SettingFile);
+
+        if (file.Exists)
+        {
+            try
+            {
+                using var stream = file.OpenRead();
+                var data = JsonSerializer.Deserialize(stream, SourceGenerationContext.Default.ConfigData);
+                settings = new Settings(data);
+            }
+            catch (Exception e)
+            {
+                throw new InvalidDataException($"Parsing settings from '{SettingFile}' failed with the following error: {e.Message}", e);
+            }
+        }
+
+        return settings;
+    }
+
+    private void OnSettingFileChange(object sender, FileSystemEventArgs e)
+    {
+        if (e.ChangeType is WatcherChangeTypes.Changed)
+        {
+            _reloadSettings = true;
+        }
+    }
+
+    private void NewExampleSettingFile()
+    {
+        string SampleContent = """
+        {
+            // To use Ollama API service:
+            // 1. Install Ollama: `winget install Ollama.Ollama`
+            // 2. Start Ollama API server: `ollama serve`
+            // 3. Install Ollama model: `ollama pull phi3`
+
+            // Declare Ollama model
+            "Model": "phi3",
+            // Declare Ollama endpoint
+            "Endpoint": "http://localhost:11434",
+            // Enable Ollama streaming
+            "Stream": false
+        }
+        """;
+        File.WriteAllText(SettingFile, SampleContent, Encoding.UTF8);
+    }
+
+    /// <summary>
+    /// Defines a generated regular expression to match localhost addresses
+    /// "localhost", "127.0.0.1" and "[::1]" with case-insensitivity.
+    /// </summary>
+    [GeneratedRegex("^(localhost|127\\.0\\.0\\.1|\\[::1\\])$", RegexOptions.IgnoreCase)]
+    internal partial Regex IsLocalHost();
 }