Optimize modules loading.

src/OrchardCore/OrchardCore.Abstractions/Modules/ModularApplicationContext.cs

@@ -1,6 +1,7 @@
-using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
 
 namespace OrchardCore.Modules
@@ -48,12 +49,17 @@ private void EnsureInitialized()
 
         private IEnumerable<Module> GetModules()
         {
-            var modules = new List<Module>();
+            var modules = new ConcurrentBag<Module>();
             modules.Add(new Module(_environment.ApplicationName, true));
 
             foreach (var provider in _moduleNamesProviders)
             {
-                modules.AddRange(provider.GetModuleNames().Select(name => new Module(name, name == _environment.ApplicationName)));
+                var names = provider.GetModuleNames().Distinct();
+
+                Parallel.ForEach(names, new ParallelOptions { MaxDegreeOfParallelism = 8 }, (name) =>
+                {
+                    modules.Add(new Module(name, name == _environment.ApplicationName));
+                });
             }
 
             return modules;

src/OrchardCore/OrchardCore/Environment/Shell/Builders/ShellContainerFactory.cs

@@ -13,7 +13,10 @@ namespace OrchardCore.Environment.Shell.Builders
 {
     public class ShellContainerFactory : IShellContainerFactory
     {
-        private readonly IFeatureInfo _applicationFeature;
+        private IFeatureInfo _applicationFeature;
+
+        private readonly IHostingEnvironment _hostingEnvironment;
+        private readonly IExtensionManager _extensionManager;
         private readonly IServiceProvider _serviceProvider;
         private readonly ILogger _logger;
         private readonly ILoggerFactory _loggerFactory;
@@ -27,9 +30,8 @@ public ShellContainerFactory(
             ILogger<ShellContainerFactory> logger,
             IServiceCollection applicationServices)
         {
-            _applicationFeature = extensionManager.GetFeatures().FirstOrDefault(
-                f => f.Id == hostingEnvironment.ApplicationName);
-
+            _hostingEnvironment = hostingEnvironment;
+            _extensionManager = extensionManager;
             _applicationServices = applicationServices;
             _serviceProvider = serviceProvider;
             _loggerFactory = loggerFactory;
@@ -84,6 +86,10 @@ public IServiceProvider CreateContainer(ShellSettings settings, ShellBlueprint b
             // OrderBy performs a stable sort so order is preserved among equal Order values.
             startups = startups.OrderBy(s => s.Order);
 
+            // To not trigger features loading before it is normally done by 'ShellHost',
+            // init here the application feature in place of doing it in the constructor.
+            EnsureApplicationFeature();
+
             // Let any module add custom service descriptors to the tenant
             foreach (var startup in startups)
             {
@@ -97,7 +103,7 @@ public IServiceProvider CreateContainer(ShellSettings settings, ShellBlueprint b
             }
 
             (moduleServiceProvider as IDisposable).Dispose();
-            
+
             var shellServiceProvider = tenantServiceCollection.BuildServiceProvider(true);
 
             // Register all DIed types in ITypeFeatureProvider
@@ -124,5 +130,20 @@ public IServiceProvider CreateContainer(ShellSettings settings, ShellBlueprint b
 
             return shellServiceProvider;
         }
+
+        private void EnsureApplicationFeature()
+        {
+            if (_applicationFeature == null)
+            {
+                lock (this)
+                {
+                    if (_applicationFeature == null)
+                    {
+                        _applicationFeature = _extensionManager.GetFeatures()
+                            .FirstOrDefault(f => f.Id == _hostingEnvironment.ApplicationName);
+                    }
+                }
+            }
+        }
     }
 }