Introduced module manager and revised module loader.

src/Volo.Abp/Volo/Abp/AbpApplication.cs

@@ -12,6 +12,8 @@ namespace Volo.Abp
 
         public IServiceProvider ServiceProvider { get; private set; }
 
+        internal AbpModuleDescriptor[] Modules { get; }
+
         private AbpApplication(
             [NotNull] Type startupModuleType,
             [NotNull] IServiceCollection services,
@@ -26,7 +28,7 @@ namespace Volo.Abp
             optionsAction?.Invoke(options);
 
             services.AddCoreAbpServices(this);
-            LoadModules(services, options);
+            Modules = LoadModules(services, options);
         }
 
         internal static AbpApplication Create<TStartupModule>([NotNull] IServiceCollection services)
@@ -66,11 +68,11 @@ namespace Volo.Abp
             ServiceProvider.GetRequiredService<IModuleLifecycleManager>().InitializeModules();
         }
 
-        private void LoadModules(IServiceCollection services, AbpApplicationCreationOptions options)
+        private AbpModuleDescriptor[] LoadModules(IServiceCollection services, AbpApplicationCreationOptions options)
         {
-            services
+            return services
                 .GetSingletonInstance<IModuleLoader>()
-                .LoadAll(
+                .LoadModules(
                     services,
                     StartupModuleType,
                     options.PlugInSources

src/Volo.Abp/Volo/Abp/Modularity/IModuleLoader.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using Microsoft.Extensions.DependencyInjection;
 using Volo.Abp.Modularity.PlugIns;
 
@@ -7,8 +6,6 @@ namespace Volo.Abp.Modularity
 {
     public interface IModuleLoader
     {
-        IReadOnlyList<AbpModuleDescriptor> Modules { get; }
-
-        void LoadAll(IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources);
+        AbpModuleDescriptor[] LoadModules(IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources);
     }
 }

src/Volo.Abp/Volo/Abp/Modularity/IModuleManager.cs

@@ -0,0 +1,9 @@
+using System.Collections.Generic;
+
+namespace Volo.Abp.Modularity
+{
+    public interface IModuleManager
+    {
+        IReadOnlyList<AbpModuleDescriptor> Modules { get; }
+    }
+}

src/Volo.Abp/Volo/Abp/Modularity/ModuleLifecycleManager.cs

@@ -5,12 +5,12 @@ namespace Volo.Abp.Modularity
 {
     public class ModuleLifecycleManager : IModuleLifecycleManager, ISingletonDependency
     {
-        private readonly IModuleLoader _moduleLoader;
+        private readonly IModuleManager _moduleManager;
         private readonly IEnumerable<IModuleLifecycleContributer> _contributers;
 
-        public ModuleLifecycleManager(IModuleLoader moduleLoader, IEnumerable<IModuleLifecycleContributer> contributers)
+        public ModuleLifecycleManager(IModuleManager moduleManager, IEnumerable<IModuleLifecycleContributer> contributers)
         {
-            _moduleLoader = moduleLoader;
+            _moduleManager = moduleManager;
             _contributers = contributers;
         }
 
@@ -18,7 +18,7 @@ namespace Volo.Abp.Modularity
         {
             foreach (var contributer in _contributers)
             {
-                foreach (var module in _moduleLoader.Modules)
+                foreach (var module in _moduleManager.Modules)
                 {
                     contributer.Initialize(module.Instance);
                 }
@@ -29,7 +29,7 @@ namespace Volo.Abp.Modularity
         {
             foreach (var contributer in _contributers)
             {
-                foreach (var module in _moduleLoader.Modules)
+                foreach (var module in _moduleManager.Modules)
                 {
                     contributer.Shutdown(module.Instance);
                 }

src/Volo.Abp/Volo/Abp/Modularity/ModuleLoader.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.Extensions.DependencyInjection;
 using Volo.Abp.Modularity.PlugIns;
@@ -10,28 +9,19 @@ namespace Volo.Abp.Modularity
 {
     public class ModuleLoader : IModuleLoader
     {
-        public IReadOnlyList<AbpModuleDescriptor> Modules => _modules.ToImmutableList();
-        private readonly List<AbpModuleDescriptor> _modules;
-
-        public ModuleLoader()
+        public AbpModuleDescriptor[] LoadModules(IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources)
         {
-            _modules = new List<AbpModuleDescriptor>();
-        }
+            var modules = new List<AbpModuleDescriptor>();
 
-        public virtual void LoadAll(IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources)
-        {
-            if (_modules.Any())
-            {
-                throw new InvalidOperationException($"{nameof(LoadAll)} should be called only once!");
-            }
+            FillModules(modules, services, startupModuleType, plugInSources);
+            SetModuleDependencies(modules);
+            SortByDependency(modules, startupModuleType);
+            ConfigureServices(modules, services);
 
-            FillModules(services, startupModuleType, plugInSources);
-            SetModuleDependencies();
-            SortByDependency(startupModuleType);
-            ConfigureServices(services);
+            return modules.ToArray();
         }
 
-        private void FillModules(IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources)
+        protected virtual void FillModules(List<AbpModuleDescriptor> modules, IServiceCollection services, Type startupModuleType, PlugInSourceList plugInSources)
         {
             //All modules starting from the startup module
             var moduleTypes = AbpModuleFinder.FindAllModuleTypes(startupModuleType);
@@ -45,23 +35,23 @@ namespace Volo.Abp.Modularity
             //Create all modules
             foreach (var moduleType in moduleTypes)
             {
-                _modules.Add(CreateModuleDescriptor(services, moduleType));
+                modules.Add(CreateModuleDescriptor(services, moduleType));
             }
         }
 
-        private void SetModuleDependencies()
+        protected virtual void SetModuleDependencies(List<AbpModuleDescriptor> modules)
         {
-            foreach (var module in Modules)
+            foreach (var module in modules)
             {
-                SetModuleDependencies(module);
+                SetModuleDependencies(modules, module);
             }
         }
         
-        private void SortByDependency(Type startupModuleType)
+        protected virtual void SortByDependency(List<AbpModuleDescriptor> modules, Type startupModuleType)
         {
-            _modules.SortByDependencies(m => m.Dependencies);
-            _modules.MoveItem(m => m.Type == typeof(AbpKernelModule), 0);
-            _modules.MoveItem(m => m.Type == startupModuleType, _modules.Count - 1);
+            modules.SortByDependencies(m => m.Dependencies);
+            modules.MoveItem(m => m.Type == typeof(AbpKernelModule), 0);
+            modules.MoveItem(m => m.Type == startupModuleType, modules.Count - 1);
         }
 
         protected virtual AbpModuleDescriptor CreateModuleDescriptor(IServiceCollection services, Type moduleType)
@@ -76,19 +66,19 @@ namespace Volo.Abp.Modularity
             return module;
         }
 
-        protected virtual void ConfigureServices(IServiceCollection services)
+        protected virtual void ConfigureServices(List<AbpModuleDescriptor> modules, IServiceCollection services)
         {
-            foreach (var module in _modules)
+            foreach (var module in modules)
             {
                 module.Instance.ConfigureServices(services);
             }
         }
         
-        protected virtual void SetModuleDependencies(AbpModuleDescriptor module)
+        protected virtual void SetModuleDependencies(List<AbpModuleDescriptor> modules, AbpModuleDescriptor module)
         {
             foreach (var dependedModuleType in AbpModuleFinder.FindDependedModuleTypes(module.Type))
             {
-                var dependedModule = _modules.FirstOrDefault(m => m.Type == dependedModuleType);
+                var dependedModule = modules.FirstOrDefault(m => m.Type == dependedModuleType);
                 if (dependedModule == null)
                 {
                     throw new AbpException("Could not find a depended module " + dependedModuleType.AssemblyQualifiedName + " for " + module.Type.AssemblyQualifiedName);

src/Volo.Abp/Volo/Abp/Modularity/ModuleManager.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using Volo.DependencyInjection;
+
+namespace Volo.Abp.Modularity
+{
+    public class ModuleManager : IModuleManager, ISingletonDependency
+    {
+        public IReadOnlyList<AbpModuleDescriptor> Modules => _modules.ToImmutableList();
+
+        private readonly List<AbpModuleDescriptor> _modules;
+
+        public ModuleManager(AbpApplication application)
+        {
+            _modules = application.Modules.ToList();
+        }
+        
+    }
+}

test/Volo.Abp.Tests/Volo/Abp/Modularity/ModuleLoader_Tests.cs

@@ -11,11 +11,11 @@ namespace Volo.Abp.Modularity
         public void Should_Load_Modules_By_Dependency_Order()
         {
             var moduleLoader = new ModuleLoader();
-            moduleLoader.LoadAll(new ServiceCollection(), typeof(MyStartupModule), new PlugInSourceList());
-            moduleLoader.Modules.Count.ShouldBe(3);
-            moduleLoader.Modules[0].Type.ShouldBe(typeof(AbpKernelModule));
-            moduleLoader.Modules[1].Type.ShouldBe(typeof(IndependentEmptyModule));
-            moduleLoader.Modules[2].Type.ShouldBe(typeof(MyStartupModule));
+            var modules = moduleLoader.LoadModules(new ServiceCollection(), typeof(MyStartupModule), new PlugInSourceList());
+            modules.Length.ShouldBe(3);
+            modules[0].Type.ShouldBe(typeof(AbpKernelModule));
+            modules[1].Type.ShouldBe(typeof(IndependentEmptyModule));
+            modules[2].Type.ShouldBe(typeof(MyStartupModule));
         }
 
         [DependsOn(typeof(IndependentEmptyModule))]