checkpoint

build/version.props

@@ -20,7 +20,7 @@
     <SystemSecurityCryptographyCspVersion>4.3.0</SystemSecurityCryptographyCspVersion>
     <SystemServiceProcessServiceControllerVersion>4.5.0</SystemServiceProcessServiceControllerVersion>
 
-    <MicrosoftNETestSdkVersion>15.9.0</MicrosoftNETestSdkVersion>
+    <MicrosoftNETestSdkVersion>16.0.1</MicrosoftNETestSdkVersion>
     <XUnitVersion>2.4.1</XUnitVersion>
     <XUnitAbstractionsVersion>2.0.3</XUnitAbstractionsVersion>
     <XUnitCoreVersion>2.4.1</XUnitCoreVersion>

src/Microsoft.IIS.Administration/Extensibility/ModuleLoader.cs

@@ -5,7 +5,8 @@
 namespace Microsoft.IIS.Administration
 {
     using AspNetCore.Hosting;
-    using Core;
+    using Core;
+    using Microsoft.IIS.Administration.Extensibility;
     using Serilog;
     using System;
     using System.Collections.Generic;
@@ -16,6 +17,7 @@ namespace Microsoft.IIS.Administration
     class ModuleLoader
     {
         private IHostingEnvironment _env;
+        private AssemblyLoadContext _loader;
         private List<Assembly> _loadedAssemblies;
         private AdminHost _moduleHolder;
         private string _moduleLoadBasePath;
@@ -28,6 +30,7 @@ namespace Microsoft.IIS.Administration
             this._moduleLoadBasePath = Path.Combine(env.ContentRootPath, PLUGINS_FOLDER_NAME);
             this._loadedAssemblies = new List<Assembly>();
             this._moduleHolder = AdminHost.Instance;
+            this._loader = new PluginAssemblyLoadContext(_moduleLoadBasePath);
         }
 
         public Assembly LoadModule(string assemblyName)
@@ -36,18 +39,14 @@ namespace Microsoft.IIS.Administration
 
             Log.Logger.Debug($"Loading plugin {assemblyName}");
 
-            var assembly = Assembly.LoadFrom(assemblyPath);
-
+            Assembly assembly = _loader.LoadFromAssemblyPath(assemblyPath);
             _loadedAssemblies.Add(assembly);
 
             //
             // Every module should expose a type called Startup in a namespace equivalent to the assembly name
             Type type = assembly.GetType(assemblyName + ".Startup");
-
-            IModule module = (IModule)Activator.CreateInstance(type);
-
+            IModule module = (IModule) Activator.CreateInstance(type);
             _moduleHolder.Add(module);
-
             return assembly;
         }
 

src/Microsoft.IIS.Administration/Extensibility/PluginAssemblyLoadContext.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+
+namespace Microsoft.IIS.Administration.Extensibility
+{
+    using Serilog;
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Linq;
+    using System.Reflection;
+    using System.Runtime.Loader;
+
+    // Implemented for https://github.com/dotnet/coreclr/issues/5837
+    // Can move back to resolver callback when fixed
+    public class PluginAssemblyLoadContext : AssemblyLoadContext
+    {
+        private string _pluginDir;
+
+        public PluginAssemblyLoadContext(string pluginDirectory)
+        {
+            this._pluginDir = pluginDirectory;
+        }
+
+        protected override Assembly Load(AssemblyName assemblyName)
+        {
+            var loaded = AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(a => a.FullName == assemblyName.FullName);
+            if (loaded != null)
+            {
+                return loaded;
+            }
+
+            Assembly asm = null;
+
+            IList<string> rootPaths = new List<string>();
+
+            rootPaths.Add(Path.Combine(this._pluginDir, $"{assemblyName.Name}.{assemblyName.Version}"));
+            rootPaths.Add(this._pluginDir);
+
+            foreach (var path in rootPaths)
+            {
+                string asmPath = Path.Combine(path, $"{assemblyName.Name}.dll");
+                Log.Logger.Debug($"Resolving plugin dependency {assemblyName} using location {asmPath}");
+                if (File.Exists(asmPath))
+                {
+                    // If LoadFromAssemblyPath's argument does not point to a valid assembly a fatal error will occur that will not throw an exception
+                    // The process will terminate ungracefully
+                    asm = this.LoadFromAssemblyPath(asmPath);
+                }
+            }
+
+            // Possible runtime assembly
+            if (asm == null)
+            {
+                string winRuntime = null;
+                string runtimes = Path.Combine(this._pluginDir, "runtimes");
+
+                if (Directory.Exists(runtimes))
+                {
+                    winRuntime = Directory.GetDirectories(runtimes).FirstOrDefault(d => d.ToLower().Contains("win"));
+                }
+
+                if (winRuntime != null)
+                {
+                    foreach (var file in Directory.GetFiles(winRuntime, "*.dll", SearchOption.AllDirectories))
+                    {
+                        if (Path.GetFileName(file) == assemblyName.Name + ".dll")
+                        {
+                            asm = this.LoadFromAssemblyPath(file);
+                            break;
+                        }
+                    }
+                }
+            }
+
+            return asm;
+        }
+    }
+}

test/Microsoft.IIS.Administration.Tests/Microsoft.IIS.Administration.Tests.csproj

@@ -24,7 +24,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(MicrosoftNETestSdkVersion)" />
-    <PackageReference Include="xunit" Version="$(XUnitVersion)" />
+    <PackageReference Include="xunit.assert" Version="2.4.1" />
+    <PackageReference Include="xunit.core" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="$(XUnitRunnerVisualStudioVersion)">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>