Merge pull request #13 from DanielMcAssey/dev/improve-plugin-loading

fix(server): improve plugin loading

GLOKON.Baiters.Core/Plugins/PluginLoader.cs

@@ -1,5 +1,6 @@
 using Serilog;
 using System.Reflection;
+using System.Runtime.Loader;
 
 namespace GLOKON.Baiters.Core.Plugins
 {
@@ -22,40 +23,42 @@ public static void LoadPlugins(GameManager gm)
             {
                 try
                 {
-                    AssemblyName thisFile = AssemblyName.GetAssemblyName(pluginPath); ;
                     pluginAssm.Add(Assembly.LoadFrom(pluginPath));
                 }
                 catch (Exception ex)
                 {
-                    Log.Error(ex, "Failed to load plugin file ({PluginPath})", pluginPath);
+                    Log.Error(ex, "Failed to load plugin file ({0})", pluginPath);
                 }
             }
 
+            AssemblyLoadContext.Default.Resolving += Default_Resolving;
+            AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
+
             foreach (var assembly in pluginAssm)
             {
-                Type[] pluginTypes = assembly.GetTypes()
-                    .Where((type) => type.IsClass && type.IsSubclassOf(typeof(BaitersPlugin)))
-                    .ToArray();
-
-                foreach (Type pluginType in pluginTypes)
+                try
                 {
-                    if (Activator.CreateInstance(pluginType, gm) is BaitersPlugin plugin)
+                    Type[] pluginTypes = assembly.GetTypes()
+                        .Where((type) => type.IsClass && type.IsSubclassOf(typeof(BaitersPlugin)))
+                        .ToArray();
+
+                    foreach (Type pluginType in pluginTypes)
                     {
-                        try
+                        if (Activator.CreateInstance(pluginType, gm) is BaitersPlugin plugin)
                         {
                             plugin.OnInit();
                             Plugins.Add(plugin);
                             Log.Information("{0}:{1} plugin loaded by {2}", plugin.Name, plugin.Version, plugin.Author);
                         }
-                        catch (Exception ex)
+                        else
                         {
-                            Log.Error(ex, "Failed to initialize plugin {0}:{1}", plugin.Name, plugin.Version);
+                            Log.Error("Failed to instantiate plugin ({0})", pluginType.FullName);
                         }
                     }
-                    else
-                    {
-                        Log.Error("Failed to create plugin ({0})", pluginType.FullName);
-                    }
+                }
+                catch (Exception ex)
+                {
+                    Log.Error(ex, "Failed to load plugin ({0})", assembly.FullName);
                 }
             }
         }
@@ -74,8 +77,37 @@ public static void UnloadPlugins()
                 }
             }
 
+            AppDomain.CurrentDomain.AssemblyResolve -= CurrentDomain_AssemblyResolve;
+            AssemblyLoadContext.Default.Resolving -= Default_Resolving;
             Plugins.Clear();
             GC.Collect();
         }
+
+        private static Assembly? Default_Resolving(AssemblyLoadContext context, AssemblyName assembly)
+        {
+            Log.Verbose("Attempting to resolve {0}", assembly);
+
+            string assemblyPath = Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, $"./plugins/{assembly.Name}.dll"));
+            return context.LoadFromAssemblyPath(assemblyPath);
+        }
+
+        private static Assembly? CurrentDomain_AssemblyResolve(object? sender, ResolveEventArgs args)
+        {
+            Assembly? assembly = null;
+
+            // Ignore version for internal dependencies
+            if (args.Name.Contains("GLOKON.Baiters.Core") || args.Name.Contains("GLOKON.Baiters.GodotInterop"))
+            {
+                var assemblyName = new AssemblyName(args.Name);
+
+                // Prevents infinte loop, as args will contain the assembly FullName once resolved
+                if (assemblyName.Name != args.Name)
+                {
+                    assembly = ((AppDomain)sender).Load(assemblyName.Name);
+                }
+            }
+
+            return assembly;
+        }
     }
 }