up

src/__Libraries/StellaOps.Messaging/Plugins/MessagingPluginLoader.cs

@@ -0,0 +1,113 @@
+using System.Reflection;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using StellaOps.Plugin;
+using StellaOps.Plugin.Hosting;
+
+namespace StellaOps.Messaging.Plugins;
+
+/// <summary>
+/// Loads and registers messaging transport plugins.
+/// </summary>
+public sealed class MessagingPluginLoader
+{
+    private readonly ILogger<MessagingPluginLoader>? _logger;
+
+    public MessagingPluginLoader(ILogger<MessagingPluginLoader>? logger = null)
+    {
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Discovers and loads messaging transport plugins from the specified directory.
+    /// </summary>
+    public IReadOnlyList<IMessagingTransportPlugin> LoadFromDirectory(
+        string pluginDirectory,
+        string searchPattern = "StellaOps.Messaging.Transport.*.dll")
+    {
+        if (!Directory.Exists(pluginDirectory))
+        {
+            _logger?.LogWarning("Plugin directory does not exist: {Directory}", pluginDirectory);
+            return [];
+        }
+
+        var options = new PluginHostOptions
+        {
+            PluginsDirectory = pluginDirectory,
+            EnsureDirectoryExists = false,
+            RecursiveSearch = false
+        };
+        options.SearchPatterns.Add(searchPattern);
+
+        var result = PluginHost.LoadPlugins(options);
+        var plugins = new List<IMessagingTransportPlugin>();
+
+        foreach (var pluginAssembly in result.Plugins)
+        {
+            var transportPlugins = PluginLoader.LoadPlugins<IMessagingTransportPlugin>(new[] { pluginAssembly.Assembly });
+            plugins.AddRange(transportPlugins);
+
+            foreach (var plugin in transportPlugins)
+            {
+                _logger?.LogDebug("Loaded messaging transport plugin: {Name} from {Assembly}",
+                    plugin.Name, pluginAssembly.Assembly.GetName().Name);
+            }
+        }
+
+        return plugins;
+    }
+
+    /// <summary>
+    /// Loads messaging transport plugins from the specified assemblies.
+    /// </summary>
+    public IReadOnlyList<IMessagingTransportPlugin> LoadFromAssemblies(IEnumerable<Assembly> assemblies)
+    {
+        return PluginLoader.LoadPlugins<IMessagingTransportPlugin>(assemblies);
+    }
+
+    /// <summary>
+    /// Finds and registers the configured transport plugin.
+    /// </summary>
+    /// <param name="plugins">Available plugins.</param>
+    /// <param name="services">Service collection.</param>
+    /// <param name="configuration">Configuration.</param>
+    /// <param name="configSectionPath">Configuration section path (default: "messaging").</param>
+    /// <returns>True if a plugin was registered.</returns>
+    public bool RegisterConfiguredTransport(
+        IReadOnlyList<IMessagingTransportPlugin> plugins,
+        IServiceCollection services,
+        IConfiguration configuration,
+        string configSectionPath = "messaging")
+    {
+        var messagingSection = configuration.GetSection(configSectionPath);
+        var transportName = messagingSection.GetValue<string>("transport");
+
+        if (string.IsNullOrWhiteSpace(transportName))
+        {
+            _logger?.LogWarning("No messaging transport configured at {Path}:transport", configSectionPath);
+            return false;
+        }
+
+        var plugin = plugins.FirstOrDefault(p =>
+            string.Equals(p.Name, transportName, StringComparison.OrdinalIgnoreCase));
+
+        if (plugin is null)
+        {
+            _logger?.LogError("Messaging transport plugin '{Transport}' not found. Available: {Available}",
+                transportName, string.Join(", ", plugins.Select(p => p.Name)));
+            return false;
+        }
+
+        var transportConfigSection = $"{configSectionPath}:{transportName}";
+        var context = new MessagingTransportRegistrationContext(
+            services,
+            configuration,
+            transportConfigSection);
+
+        plugin.Register(context);
+
+        _logger?.LogInformation("Registered messaging transport: {Transport}", transportName);
+        return true;
+    }
+}