Make logging optional in all public APIs (#72)

Author: stephentoub

src/mcpdotnet/Client/McpClientFactory.cs

@@ -4,6 +4,7 @@
 using McpDotNet.Logging;
 using McpDotNet.Protocol.Transport;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
 
 namespace McpDotNet.Client;
 /// <summary>
@@ -43,10 +44,22 @@ public class McpClientFactory : IDisposable
     public McpClientFactory(
         IEnumerable<McpServerConfig> serverConfigs,
         McpClientOptions clientOptions,
-        ILoggerFactory loggerFactory,
+        ILoggerFactory? loggerFactory = null,
         Func<McpServerConfig, IClientTransport>? transportFactoryMethod = null,
         Func<IClientTransport, McpServerConfig, McpClientOptions, IMcpClient>? clientFactoryMethod = null)
     {
+        if (serverConfigs is null)
+        {
+            throw new ArgumentNullException(nameof(serverConfigs));
+        }
+
+        if (clientOptions is null)
+        {
+            throw new ArgumentNullException(nameof(clientOptions));
+        }
+
+        loggerFactory ??= NullLoggerFactory.Instance;
+
         _serverConfigs = serverConfigs.ToDictionary(c => c.Id);
         _clientOptions = clientOptions;
         _loggerFactory = loggerFactory;

src/mcpdotnet/Protocol/Transport/StdioClientTransport.cs

@@ -8,6 +8,7 @@
 using McpDotNet.Utils;
 using McpDotNet.Utils.Json;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
 
 namespace McpDotNet.Protocol.Transport;
 
@@ -18,7 +19,7 @@ public sealed class StdioClientTransport : TransportBase, IClientTransport
 {
     private readonly StdioClientTransportOptions _options;
     private readonly McpServerConfig _serverConfig;
-    private readonly ILogger<StdioClientTransport> _logger;
+    private readonly ILogger _logger;
     private readonly JsonSerializerOptions _jsonOptions;
     private Process? _process;
     private Task? _readTask;
@@ -33,12 +34,22 @@ public sealed class StdioClientTransport : TransportBase, IClientTransport
     /// <param name="options">Configuration options for the transport.</param>
     /// <param name="serverConfig">The server configuration for the transport.</param>
     /// <param name="loggerFactory">A logger factory for creating loggers.</param>
-    public StdioClientTransport(StdioClientTransportOptions options, McpServerConfig serverConfig, ILoggerFactory loggerFactory)
+    public StdioClientTransport(StdioClientTransportOptions options, McpServerConfig serverConfig, ILoggerFactory? loggerFactory = null)
         : base(loggerFactory)
     {
+        if (options is null)
+        {
+            throw new ArgumentNullException(nameof(options));
+        }
+
+        if (serverConfig is null)
+        {
+            throw new ArgumentNullException(nameof(serverConfig));
+        }
+
         _options = options;
         _serverConfig = serverConfig;
-        _logger = loggerFactory.CreateLogger<StdioClientTransport>();
+        _logger = (ILogger?)loggerFactory?.CreateLogger<StdioClientTransport>() ?? NullLogger.Instance;
         _jsonOptions = JsonSerializerOptionsExtensions.DefaultOptions;
     }
 

src/mcpdotnet/Server/McpServerFactory.cs

@@ -1,5 +1,6 @@
 using McpDotNet.Protocol.Transport;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 
 namespace McpDotNet.Server;
@@ -31,11 +32,16 @@ public class McpServerFactory : IMcpServerFactory
     /// <param name="serviceProvider">Optional service provider to create new instances.</param>
     /// <param name="loggerFactory">Logger factory to use for logging</param>
     /// <param name="serverDelegates"></param>
-    public McpServerFactory(IServerTransport serverTransport, McpServerOptions options, ILoggerFactory loggerFactory, IOptions<McpServerDelegates>? serverDelegates = null, IServiceProvider? serviceProvider = null)
+    public McpServerFactory(
+        IServerTransport serverTransport,
+        McpServerOptions options,
+        ILoggerFactory? loggerFactory = null,
+        IOptions<McpServerDelegates>? serverDelegates = null,
+        IServiceProvider? serviceProvider = null)
     {
         _serverTransport = serverTransport ?? throw new ArgumentNullException(nameof(serverTransport));
         _options = options ?? throw new ArgumentNullException(nameof(options));
-        _loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
+        _loggerFactory = loggerFactory ?? NullLoggerFactory.Instance;
         _serverDelegates = serverDelegates?.Value;
         _serviceProvider = serviceProvider;
     }

tests/mcpdotnet.Tests/Server/McpServerFactoryTests.cs

@@ -53,13 +53,6 @@ public void Constructor_Throws_For_Null_Options()
         Assert.Throws<ArgumentNullException>(() => new McpServerFactory(_serverTransport.Object, null!, _loggerFactory.Object, _serverDelegates.Object, _serviceProvider));
     }
 
-    [Fact]
-    public void Constructor_Throws_For_Null_Logger()
-    {
-        // Arrange, Act & Assert
-        Assert.Throws<ArgumentNullException>(() => new McpServerFactory(_serverTransport.Object, _options, null!, _serverDelegates.Object, _serviceProvider));
-    }
-
     [Fact]
     public void Constructor_Does_Not_Throw_For_Null_ServerDelegates()
     {