Implemented basic transaction API.

src/Volo.Abp.EntityFrameworkCore/Volo.Abp.EntityFrameworkCore.csproj

@@ -17,6 +17,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.0.0" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="2.0.0" />
   </ItemGroup>
 
 </Project>

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/DatabaseFacadeExtensions.cs

@@ -0,0 +1,14 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Volo.Abp.EntityFrameworkCore
+{
+    public static class DatabaseFacadeExtensions
+    {
+        public static bool IsRelational(this DatabaseFacade database)
+        {
+            return database.GetInfrastructure().GetService<IRelationalConnection>() != null;
+        }
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/DbContextExtensions.cs

@@ -0,0 +1,14 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace Volo.Abp.EntityFrameworkCore
+{
+    internal static class DbContextExtensions
+    {
+        public static bool HasRelationalTransactionManager(this DbContext dbContext)
+        {
+            return dbContext.Database.GetService<IDbContextTransactionManager>() is IRelationalTransactionManager;
+        }
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/DependencyInjection/DbContextCreationContext.cs

@@ -1,9 +1,10 @@
 using System;
+using System.Data.Common;
 using System.Threading;
 
 namespace Volo.Abp.EntityFrameworkCore.DependencyInjection
 {
-    internal class DbContextCreationContext
+    public class DbContextCreationContext
     {
         public static DbContextCreationContext Current => _current.Value;
         private static readonly AsyncLocal<DbContextCreationContext> _current = new AsyncLocal<DbContextCreationContext>();
@@ -12,6 +13,8 @@ namespace Volo.Abp.EntityFrameworkCore.DependencyInjection
 
         public string ConnectionString { get; }
 
+        public DbConnection ExistingConnection { get; set; }
+
         public DbContextCreationContext(string connectionStringName, string connectionString)
         {
             ConnectionStringName = connectionStringName;

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/EntityFrameworkCore/DependencyInjection/DbContextOptionsFactory.cs

@@ -12,39 +12,37 @@ namespace Volo.Abp.EntityFrameworkCore.DependencyInjection
         public static DbContextOptions<TDbContext> Create<TDbContext>(IServiceProvider serviceProvider)
             where TDbContext : AbpDbContext<TDbContext>
         {
-            using (var scope = serviceProvider.CreateScope())
-            {
-                var creationContext = GetCreationContext<TDbContext>(scope.ServiceProvider);
-
-                var context = new AbpDbContextConfigurationContext<TDbContext>(
-                    creationContext.ConnectionString,
-                    creationContext.ConnectionStringName,
-                    scope.ServiceProvider
-                );
+            var creationContext = GetCreationContext<TDbContext>(serviceProvider);
 
-                var dbContextOptions = GetDbContextOptions<TDbContext>(scope);
+            var context = new AbpDbContextConfigurationContext<TDbContext>(
+                creationContext.ConnectionString,
+                creationContext.ConnectionStringName,
+                serviceProvider
+            );
 
-                var configureAction = dbContextOptions.ConfigureActions.GetOrDefault(typeof(TDbContext));
-                if (configureAction != null)
-                {
-                    ((Action<AbpDbContextConfigurationContext<TDbContext>>)configureAction).Invoke(context);
-                }
-                else if (dbContextOptions.DefaultConfigureAction != null)
-                {
-                    dbContextOptions.DefaultConfigureAction.Invoke(context);
-                }
-                else
-                {
-                    throw new AbpException($"No configuration found for {typeof(DbContext).AssemblyQualifiedName}! Use services.Configure<AbpDbContextOptions>(...) to configure it.");
-                }
+            var dbContextOptions = GetDbContextOptions<TDbContext>(serviceProvider);
 
-                return context.DbContextOptions.Options;
+            var configureAction = dbContextOptions.ConfigureActions.GetOrDefault(typeof(TDbContext));
+            if (configureAction != null)
+            {
+                ((Action<AbpDbContextConfigurationContext<TDbContext>>)configureAction).Invoke(context);
+            }
+            else if (dbContextOptions.DefaultConfigureAction != null)
+            {
+                dbContextOptions.DefaultConfigureAction.Invoke(context);
+            }
+            else
+            {
+                throw new AbpException($"No configuration found for {typeof(DbContext).AssemblyQualifiedName}! Use services.Configure<AbpDbContextOptions>(...) to configure it.");
             }
+
+            return context.DbContextOptions.Options;
         }
 
-        private static AbpDbContextOptions GetDbContextOptions<TDbContext>(IServiceScope scope) where TDbContext : AbpDbContext<TDbContext>
+        private static AbpDbContextOptions GetDbContextOptions<TDbContext>(IServiceProvider serviceProvider)
+            where TDbContext : AbpDbContext<TDbContext>
         {
-            return scope.ServiceProvider.GetRequiredService<IOptions<AbpDbContextOptions>>().Value;
+            return serviceProvider.GetRequiredService<IOptions<AbpDbContextOptions>>().Value;
         }
 
         private static DbContextCreationContext GetCreationContext<TDbContext>(IServiceProvider serviceProvider)

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/DbContextEfCoreTransactionStrategy.cs

@@ -0,0 +1,46 @@
+using System.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage;
+using Microsoft.Extensions.DependencyInjection;
+using Volo.Abp.DependencyInjection;
+using Volo.Abp.EntityFrameworkCore;
+using Volo.Abp.EntityFrameworkCore.DependencyInjection;
+
+namespace Volo.Abp.Uow.EntityFrameworkCore
+{
+    public class DbContextEfCoreTransactionStrategy : IEfCoreTransactionStrategy, ITransientDependency
+    {
+        public TDbContext CreateDbContext<TDbContext>(IUnitOfWork unitOfWork, DbContextCreationContext creationContext) where TDbContext : DbContext
+        {
+            var transactionApiKey = $"EntityFrameworkCore_{creationContext.ConnectionString}";
+            var activeTransaction = unitOfWork.FindTransactionApi(transactionApiKey) as IEfCoreTransactionApi;
+
+            TDbContext dbContext;
+            if (activeTransaction == null)
+            {
+                dbContext = unitOfWork.ServiceProvider.GetRequiredService<TDbContext>();
+                var dbtransaction = dbContext.Database.BeginTransaction((unitOfWork.Options.IsolationLevel ?? IsolationLevel.ReadUncommitted));
+                activeTransaction = new EfCoreTransactionApi(dbtransaction, dbContext);
+                unitOfWork.AddTransactionApi(transactionApiKey, activeTransaction);
+            }
+            else
+            {
+                creationContext.ExistingConnection = activeTransaction.DbContextTransaction.GetDbTransaction().Connection;
+                dbContext = unitOfWork.ServiceProvider.GetRequiredService<TDbContext>();
+                
+                if (dbContext.HasRelationalTransactionManager())
+                {
+                    dbContext.Database.UseTransaction(activeTransaction.DbContextTransaction.GetDbTransaction());
+                }
+                else
+                {
+                    dbContext.Database.BeginTransaction();
+                }
+
+                activeTransaction.AttendedDbContexts.Add(dbContext);
+            }
+
+            return dbContext;
+        }
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/EfCoreTransactionApi.cs

@@ -0,0 +1,48 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage;
+using Volo.Abp.EntityFrameworkCore;
+
+namespace Volo.Abp.Uow.EntityFrameworkCore
+{
+    public class EfCoreTransactionApi : IEfCoreTransactionApi
+    {
+        public IDbContextTransaction DbContextTransaction { get; }
+        public DbContext StarterDbContext { get; }
+        public List<DbContext> AttendedDbContexts { get; }
+
+        public EfCoreTransactionApi(IDbContextTransaction dbContextTransaction, DbContext starterDbContext)
+        {
+            DbContextTransaction = dbContextTransaction;
+            StarterDbContext = starterDbContext;
+            AttendedDbContexts = new List<DbContext>();
+        }
+
+        public void Commit()
+        {
+            DbContextTransaction.Commit();
+
+            foreach (var dbContext in AttendedDbContexts)
+            {
+                if (dbContext.HasRelationalTransactionManager())
+                {
+                    continue; //Relational databases use the shared transaction
+                }
+
+                dbContext.Database.CommitTransaction();
+            }
+        }
+
+        public Task CommitAsync()
+        {
+            Commit();
+            return Task.CompletedTask;
+        }
+
+        public void Dispose()
+        {
+            DbContextTransaction.Dispose();
+        }
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/IEfCoreTransactionApi.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace Volo.Abp.Uow.EntityFrameworkCore
+{
+    public interface IEfCoreTransactionApi : ITransactionApi
+    {
+        IDbContextTransaction DbContextTransaction { get; }
+
+        DbContext StarterDbContext { get; }
+
+        List<DbContext> AttendedDbContexts { get; }
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/IEfCoreTransactionStrategy.cs

@@ -0,0 +1,11 @@
+using Microsoft.EntityFrameworkCore;
+using Volo.Abp.EntityFrameworkCore.DependencyInjection;
+
+namespace Volo.Abp.Uow.EntityFrameworkCore
+{
+    public interface IEfCoreTransactionStrategy
+    {
+        TDbContext CreateDbContext<TDbContext>(IUnitOfWork unitOfWork, DbContextCreationContext creationContext)
+            where TDbContext : DbContext;
+    }
+}

src/Volo.Abp.EntityFrameworkCore/Volo/Abp/Uow/EntityFrameworkCore/UnitOfWorkDbContextProvider.cs

@@ -1,3 +1,5 @@
+using System;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Volo.Abp.Data;
 using Volo.Abp.EntityFrameworkCore;
@@ -5,18 +7,23 @@ using Volo.Abp.EntityFrameworkCore.DependencyInjection;
 
 namespace Volo.Abp.Uow.EntityFrameworkCore
 {
+    //TODO: Implement logic in DefaultDbContextResolver.Resolve in old ABP.
+
     public class UnitOfWorkDbContextProvider<TDbContext> : IDbContextProvider<TDbContext>
         where TDbContext : AbpDbContext<TDbContext>
     {
         private readonly IUnitOfWorkManager _unitOfWorkManager;
         private readonly IConnectionStringResolver _connectionStringResolver;
+        private readonly IEfCoreTransactionStrategy _transactionStrategy;
 
         public UnitOfWorkDbContextProvider(
             IUnitOfWorkManager unitOfWorkManager,
-            IConnectionStringResolver connectionStringResolver)
+            IConnectionStringResolver connectionStringResolver,
+            IEfCoreTransactionStrategy transactionStrategy)
         {
             _unitOfWorkManager = unitOfWorkManager;
             _connectionStringResolver = connectionStringResolver;
+            _transactionStrategy = transactionStrategy;
         }
 
         public TDbContext GetDbContext()
@@ -41,12 +48,30 @@ namespace Volo.Abp.Uow.EntityFrameworkCore
             return ((DbContextDatabaseApi<TDbContext>)databaseApi).DbContext;
         }
 
-        private static TDbContext CreateDbContext(IUnitOfWork unitOfWork, string connectionStringName, string connectionString)
+        private TDbContext CreateDbContext(IUnitOfWork unitOfWork, string connectionStringName, string connectionString)
         {
             var creationContext = new DbContextCreationContext(connectionStringName, connectionString);
             using (DbContextCreationContext.Use(creationContext))
             {
-                return unitOfWork.ServiceProvider.GetRequiredService<TDbContext>();
+                TDbContext dbContext;
+
+                if (unitOfWork.Options.IsTransactional == true)
+                {
+                    dbContext = _transactionStrategy.CreateDbContext<TDbContext>(unitOfWork, creationContext);
+                }
+                else
+                {
+                    dbContext = unitOfWork.ServiceProvider.GetRequiredService<TDbContext>();
+                }
+
+                if (unitOfWork.Options.Timeout.HasValue &&
+                    dbContext.Database.IsRelational() &&
+                    !dbContext.Database.GetCommandTimeout().HasValue)
+                {
+                    dbContext.Database.SetCommandTimeout(unitOfWork.Options.Timeout.Value.TotalSeconds.To<int>());
+                }
+
+                return dbContext;
             }
         }
     }

src/Volo.Abp/Volo/Abp/Uow/ChildUnitOfWork.cs

@@ -83,7 +83,17 @@ namespace Volo.Abp.Uow
         {
             return _parent.GetOrAddDatabaseApi(key, factory);
         }
-        
+
+        public ITransactionApi FindTransactionApi(string key)
+        {
+            return _parent.FindTransactionApi(key);
+        }
+
+        public void AddTransactionApi(string key, ITransactionApi api)
+        {
+            _parent.AddTransactionApi(key, api);
+        }
+
         public void Dispose()
         {
 

src/Volo.Abp/Volo/Abp/Uow/ITransactionApi.cs

@@ -0,0 +1,13 @@
+using System.Threading.Tasks;
+
+namespace Volo.Abp.Uow
+{
+    public interface ITransactionApi
+    {
+        void Commit();
+
+        Task CommitAsync();
+
+        void Dispose();
+    }
+}

src/Volo.Abp/Volo/Abp/Uow/ITransactionApiContainer.cs

@@ -0,0 +1,12 @@
+using JetBrains.Annotations;
+
+namespace Volo.Abp.Uow
+{
+    public interface ITransactionApiContainer
+    {
+        [CanBeNull]
+        ITransactionApi FindTransactionApi([NotNull] string key);
+
+        void AddTransactionApi([NotNull] string key, [NotNull] ITransactionApi api);
+    }
+}

src/Volo.Abp/Volo/Abp/Uow/IUnitOfWork.cs

@@ -2,7 +2,7 @@
 
 namespace Volo.Abp.Uow
 {
-    public interface IUnitOfWork : IBasicUnitOfWork, IDatabaseApiContainer
+    public interface IUnitOfWork : IBasicUnitOfWork, IDatabaseApiContainer, ITransactionApiContainer
     {
         UnitOfWorkStartOptions Options { get; }
 

src/Volo.Abp/Volo/Abp/Uow/UnitOfWork.cs

@@ -35,6 +35,7 @@ namespace Volo.Abp.Uow
         public IServiceProvider ServiceProvider { get; }
 
         private readonly Dictionary<string, IDatabaseApi> _databaseApis;
+        private readonly Dictionary<string, ITransactionApi> _transactionApis;
 
         private Exception _exception;
         private bool _isCompleted;
@@ -45,6 +46,7 @@ namespace Volo.Abp.Uow
             ServiceProvider = serviceProvider;
 
             _databaseApis = new Dictionary<string, IDatabaseApi>();
+            _transactionApis = new Dictionary<string, ITransactionApi>();
         }
 
         public void SaveChanges()
@@ -72,6 +74,7 @@ namespace Volo.Abp.Uow
             try
             {
                 SaveChanges();
+                CommitTransactions();
                 OnCompleted();
             }
             catch (Exception ex)
@@ -88,6 +91,7 @@ namespace Volo.Abp.Uow
             try
             {
                 await SaveChangesAsync(cancellationToken);
+                await CommitTransactionsAsync();
                 OnCompleted();
             }
             catch (Exception ex)
@@ -110,6 +114,26 @@ namespace Volo.Abp.Uow
             return _databaseApis.GetOrAdd(key, factory);
         }
 
+        public ITransactionApi FindTransactionApi(string key)
+        {
+            Check.NotNull(key, nameof(key));
+
+            return _transactionApis.GetOrDefault(key);
+        }
+
+        public void AddTransactionApi(string key, ITransactionApi api)
+        {
+            Check.NotNull(key, nameof(key));
+            Check.NotNull(api, nameof(api));
+
+            if (_transactionApis.ContainsKey(key))
+            {
+                throw new AbpException("There is already a transaction API in this unit of work!");
+            }
+
+            _transactionApis.Add(key, api);
+        }
+
         protected virtual void OnCompleted()
         {
             Completed.InvokeSafely(this);
@@ -156,5 +180,21 @@ namespace Volo.Abp.Uow
         {
             return $"[UnitOfWork {Id}]";
         }
+
+        protected virtual void CommitTransactions()
+        {
+            foreach (var transaction in _transactionApis.Values)
+            {
+                transaction.Commit();
+            }
+        }
+
+        protected virtual async Task CommitTransactionsAsync()
+        {
+            foreach (var transaction in _transactionApis.Values)
+            {
+                await transaction.CommitAsync();
+            }
+        }
     }
 }