Initial support for configurable AI agents

.netconfig

@@ -159,3 +159,8 @@
 	sha = 666a2a7c315f72199c418f11482a950fc69a8901
 	etag = 91ea15c07bfd784036c6ca931f5b2df7e9767b8367146d96c79caef09d63899f
 	weak
+[file "src/Agents/Extensions/Throw.cs"]
+	url = https://github.com/devlooped/catbag/blob/main/System/Throw.cs
+	sha = 3012d56be7554c483e5c5d277144c063969cada9
+	etag = 43c81c6c6dcdf5baee40a9e3edc5e871e473e6c954c901b82bb87a3a48888ea0
+	weak

src/Agents/AddAIAgentsExtensions.cs

@@ -0,0 +1,45 @@
+using Devlooped.Extensions.AI;
+using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hosting;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace Devlooped.Agents.AI;
+
+public static class AddAIAgentsExtensions
+{
+    public static IHostApplicationBuilder AddAIAgents(this IHostApplicationBuilder builder, Action<string, AIAgentBuilder>? configurePipeline = default, Action<string, ChatClientAgentOptions>? configureOptions = default, string prefix = "ai:agents")
+    {
+        builder.AddChatClients();
+
+        foreach (var entry in builder.Configuration.AsEnumerable().Where(x =>
+            x.Key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) &&
+            x.Key.EndsWith("client", StringComparison.OrdinalIgnoreCase)))
+        {
+            var section = string.Join(':', entry.Key.Split(':')[..^1]);
+            // key == name (unlike chat clients, the AddAIAgent expects the key to be the name). 
+            var name = builder.Configuration[$"{section}:name"] ?? section[(prefix.Length + 1)..];
+
+            var options = builder.Configuration.GetRequiredSection(section).Get<ChatClientAgentOptions>();
+            // We need logging set up for the configurable client to log changes
+            builder.Services.AddLogging();
+
+            builder.AddAIAgent(name, (sp, key) =>
+            {
+                var agent = new ConfigurableAIAgent(sp, section, key, configureOptions);
+
+                if (configurePipeline is not null)
+                {
+                    var builder = agent.AsBuilder();
+                    configurePipeline(key, builder);
+                    return builder.Build(sp);
+                }
+
+                return agent;
+            });
+        }
+
+        return builder;
+    }
+}

src/Agents/Agents.csproj

@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net8.0;net9.0;net10.0</TargetFrameworks>
+    <TargetFrameworks>net8.0;net9.0;net10.0</TargetFrameworks>
     <LangVersion>Preview</LangVersion>
-    <PackageId>Devlooped.Agents.AI</PackageId>
+    <AssemblyName>Devlooped.Agents.AI</AssemblyName>
+    <RootNamespace>$(AssemblyName)</RootNamespace>
+    <PackageId>$(AssemblyName)</PackageId>
     <Description>Extensions for Microsoft.Agents.AI</Description>
     <PackageLicenseExpression></PackageLicenseExpression>
     <PackageLicenseFile>OSMFEULA.txt</PackageLicenseFile>
@@ -13,8 +15,10 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.9" />
     <PackageReference Include="NuGetizer" Version="1.3.1" PrivateAssets="all" />
     <PackageReference Include="Microsoft.Agents.AI" Version="1.0.0-preview.251009.1" />
+    <PackageReference Include="Microsoft.Agents.AI.Hosting" Version="1.0.0-preview.251009.1" />
     <PackageReference Include="Microsoft.Agents.AI.AzureAI" Version="1.0.0-preview.251009.1" />
     <PackageReference Include="Microsoft.Agents.AI.OpenAI" Version="1.0.0-preview.251009.1" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="9.0.9" />
@@ -25,4 +29,8 @@
     <None Include="..\..\osmfeula.txt" Link="osmfeula.txt" PackagePath="OSMFEULA.txt" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\Extensions\Extensions.csproj" />
+  </ItemGroup>
+
 </Project>

src/Agents/ConfigurableAIAgent.cs

@@ -0,0 +1,99 @@
+using System.Text.Json;
+using Microsoft.Agents.AI;
+using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace Devlooped.Agents.AI;
+
+public sealed partial class ConfigurableAIAgent : AIAgent, IDisposable
+{
+    readonly IServiceProvider services;
+    readonly IConfiguration configuration;
+    readonly string section;
+    readonly string name;
+    readonly ILogger logger;
+    readonly Action<string, ChatClientAgentOptions>? configure;
+    IDisposable reloadToken;
+    ChatClientAgent agent;
+    IChatClient chat;
+    ChatClientAgentOptions options;
+
+    public ConfigurableAIAgent(IServiceProvider services, string section, string name, Action<string, ChatClientAgentOptions>? configure)
+    {
+        if (section.Contains('.'))
+            throw new ArgumentException("Section separator must be ':', not '.'");
+
+        this.services = Throw.IfNull(services);
+        this.configuration = services.GetRequiredService<IConfiguration>();
+        this.logger = services.GetRequiredService<ILogger<ConfigurableAIAgent>>();
+        this.section = Throw.IfNullOrEmpty(section);
+        this.name = Throw.IfNullOrEmpty(name);
+        this.configure = configure;
+
+        (agent, options, chat) = Configure(configuration.GetRequiredSection(section));
+        reloadToken = configuration.GetReloadToken().RegisterChangeCallback(OnReload, state: null);
+    }
+
+    public void Dispose() => reloadToken?.Dispose();
+
+    public override object? GetService(Type serviceType, object? serviceKey = null) => serviceType switch
+    {
+        Type t when t == typeof(ChatClientAgentOptions) => options,
+        Type t when t == typeof(IChatClient) => chat,
+        _ => agent.GetService(serviceType, serviceKey)
+    };
+
+    public override string Id => agent.Id;
+    public override string? Description => agent.Description;
+    public override string DisplayName => agent.DisplayName;
+    public override string? Name => agent.Name;
+    public override AgentThread DeserializeThread(JsonElement serializedThread, JsonSerializerOptions? jsonSerializerOptions = null)
+        => agent.DeserializeThread(serializedThread, jsonSerializerOptions);
+    public override AgentThread GetNewThread() => agent.GetNewThread();
+    public override Task<AgentRunResponse> RunAsync(IEnumerable<ChatMessage> messages, AgentThread? thread = null, AgentRunOptions? options = null, CancellationToken cancellationToken = default)
+        => agent.RunAsync(messages, thread, options, cancellationToken);
+    public override IAsyncEnumerable<AgentRunResponseUpdate> RunStreamingAsync(IEnumerable<ChatMessage> messages, AgentThread? thread = null, AgentRunOptions? options = null, CancellationToken cancellationToken = default)
+        => agent.RunStreamingAsync(messages, thread, options, cancellationToken);
+
+    (ChatClientAgent, ChatClientAgentOptions, IChatClient) Configure(IConfigurationSection configSection)
+    {
+        var options = configSection.Get<AgentClientOptions>();
+        options?.Name ??= name;
+
+        // If there was a custom id, we must validate it didn't change since that's not supported.
+        if (configuration[$"{section}:name"] is { } newname && newname != name)
+            throw new InvalidOperationException($"The name of a configured agent cannot be changed at runtime. Expected '{name}' but was '{newname}'.");
+
+        var client = services.GetRequiredKeyedService<IChatClient>(options?.Client
+            ?? throw new InvalidOperationException($"A client must be specified for agent '{name}' in configuration section '{section}'."));
+
+        var chat = configSection.GetSection("options").Get<ChatOptions>();
+        if (chat is not null)
+            options.ChatOptions = chat;
+
+        configure?.Invoke(name, options);
+
+        LogConfigured(name);
+
+        return (new ChatClientAgent(client, options, services.GetRequiredService<ILoggerFactory>(), services), options, client);
+    }
+
+    void OnReload(object? state)
+    {
+        var configSection = configuration.GetRequiredSection(section);
+        reloadToken?.Dispose();
+        chat?.Dispose();
+        (agent, options, chat) = Configure(configSection);
+        reloadToken = configuration.GetReloadToken().RegisterChangeCallback(OnReload, state: null);
+    }
+
+    [LoggerMessage(LogLevel.Information, "AIAgent '{Id}' configured.")]
+    private partial void LogConfigured(string id);
+
+    class AgentClientOptions : ChatClientAgentOptions
+    {
+        public required string Client { get; set; }
+    }
+}