我有一个命令行程序,该程序将数据导入到我的系统中。因为它将数据插入许多表中,所以我需要进行更改跟踪。为了尝试防止作业随时间推移而变慢,我使用了Autofac(我的依赖项注入框架)来创建一个内部生命周期范围,从中可以解析依赖项。在每个批处理的末尾,我将重新创建生存期范围并获取依赖项的新实例。问题是,当我这样做时,UnitOfWork依赖的DataContext不会每次都刷新,从而导致作业变慢,并最终在完成之前终止。
在调试时,我可以在DbContext上设置“ Make Object ID”,例如
每批处理后,对象ID仍为$ 2,表明DataContext实例未获取新实例。为什么没有获得新实例?
我的代码如下所示:
foreach (var batch in data.Batch(10))
{
using (var scope = LifetimeScope.BeginLifetimeScope(b =>
{
b.RegisterType<UnitOfWork>.AsImplementedInterfaces().PropertiesAutowired().InstancePerLifetimeScope();
b.RegisterType<MyService1>.AsImplementedInterfaces().PropertiesAutowired().InstancePerLifetimeScope();
b.RegisterType<MyService2>.AsImplementedInterfaces().PropertiesAutowired().InstancePerLifetimeScope();
b.RegisterGeneric(typeof(EntityBaseRepository<>)).As(typeof(IEntityBaseRepository<>)).InstancePerLifetimeScope();
}))
{
UnitOfWork = scope.Resolve<IUnitOfWork>();
MyService1 = scope.Resolve<IMyService1>();
MyService2 = scope.Resolve<IMyService2>();
Thing1Repository = scope.Resolve<IEntityBaseRepository<Thing1Repository>>();
Thing2Repository = scope.Resolve<IEntityBaseRepository<Thing2Repository>>();
foreach (var row in batch)
{
try
{
ParseRow(row);
}
catch (Exception e)
{
JobLogger.Error(e, "Failed to parse row. Exception: " + e.Message);
throw;
}
}
}
}
据我了解,当我获得依赖项的新实例时,子依赖项也将获得新的实例吗?为什么原始DataContext仍然悬而未决?
我的UnitOfWork看起来像这样:
public class UnitOfWork : Disposable, IUnitOfWork
{
private readonly IDbFactory _dbFactory;
private DataContext _dbContext;
public UnitOfWork(IDbFactory dbFactory)
{
_dbFactory = dbFactory;
}
public DataContext DbContext => _dbContext ?? (_dbContext = _dbFactory.Initialise());
public void Commit()
{
DbContext.Commit();
}
}
我的DbFactory负责创建DataContext的新实例:
public class DbFactory : Disposable, IDbFactory
{
DataContext _dbContext;
public DbFactory()
{
_dbContext = new DataContext();
}
public DataContext Initialise()
{
return _dbContext ?? (_dbContext = new DataContext());
}
protected override void DisposeCore()
{
_dbContext?.Dispose();
}
}
在程序首次通过调用此方法启动时,通过扫描程序集来注册我的服务:
AutofacConfig.InitialiseJobRunner();
在此方法中,我这样注册我的类型:
builder.RegisterType<DataContext>().AsSelf().InstancePerMatchingLifetimeScope(lifetimeScope);
builder.RegisterGenericInstance(typeof(EntityBaseRepository<>), typeof(IEntityBaseRepository<>), lifetimeScope);
builder.RegisterAssemblyInterfaces(Assembly.Load(Data), lifetimeScope);
RegisterAssemblyInterfaces实现为:
public static IRegistrationBuilder<object, ScanningActivatorData, DynamicRegistrationStyle>
RegisterAssemblyInterfaces(this ContainerBuilder builder, Assembly assembly, object lifetimeScope)
{
return builder.RegisterAssemblyTypes(assembly)
.AsImplementedInterfaces()
.InstancePerMatchingLifetimeScope(lifetimeScope);
}
答案 0 :(得分:2)
如你注册组件接口,如以下
public static IRegistrationBuilder<object, ScanningActivatorData, DynamicRegistrationStyle>
RegisterAssemblyInterfaces(this ContainerBuilder builder, Assembly assembly, object lifetimeScope)
{
return builder.RegisterAssemblyTypes(assembly)
.AsImplementedInterfaces()
.InstancePerMatchingLifetimeScope(lifetimeScope);
}
我的猜测是您的DbFactory也以这种方式注册。在这种情况下(根据https://autofac.readthedocs.io/en/latest/lifetime/instance-scope.html#instance-per-matching-lifetime-scope),您将获得与工厂相同的实例,因为未命名子作用域。尝试添加
b.RegisterType<DbFactory>.AsImplementedInterfaces().PropertiesAutowired().InstancePerLifetimeScope();
在循环中或将DbFactory更改为始终在Initialize方法中返回新的上下文,而不是如果已实例化则返回相同的上下文。