asp.net - EF Core 中的错误:在前一个操作完成之前在此上下文中启动了第二个操作
问题描述
我的 web api 应用程序出现奇怪的错误:在前一个操作完成之前,在此上下文中启动了第二个操作。不保证任何实例成员都是线程安全的。
我有一个流程来计算用户的发薪日并更新其用户休假余额。所以我需要迭代用户并获得其休假余额,然后对每个余额进行更新。我还不知道如何解决这个错误。当我调用 this.SaveAll() 时触发的错误是 containsb
public async Task<bool> SaveAll()
{
return await _context.SaveChangesAsync() > 0;
}
datacontext 也被注入此代码:
private readonly DataContext _context;
private readonly IAdminSettingsRepository _settingRepo;
private readonly IAppRepository _appRepository;
public PayrollRepository(DataContext context, IAdminSettingsRepository settingRepo, IAppRepository appRepository)
{
_context = context;
_settingRepo = settingRepo;
_appRepository = appRepository;
}
过程如下:
public async Task<bool> ProcessPayCalendar(PayCalendar payCalendar)
{
List<User> users = payCalendar.Users.ToList();
SickLeaveEntitlement sickLeaveEntitlement = await _settingRepo.GetSickLeaveEntitlement();
AnnualLeaveEntitlement annualLeaveEntitlement = await _settingRepo.GetAnnualLeaveEntitlement();
LongServiceLeaveEntitlement longServiceLeaveEntitlement = await _settingRepo.GetLongServiceLeaveEntitlement();
DateTime tenYearsAgo = DateTime.Today.AddYears(-10);
DateTime currentMonth = new DateTime(payCalendar.NextPaymentDate.Year, payCalendar.NextPaymentDate.Month, 1);
DateTime previousMonth = currentMonth.AddMonths(-1);
/// begin calculation for leave calendar
users.ForEach(async user =>
{
decimal hoursWorked = this.CalculateWorkingHours(user);
decimal hourlyRate = this.CalculateHourlyRate(user);
// create pay day for user
Payday payday = new Payday();
payday.UserId = user.Id;
payday.PayPeriodStart = payCalendar.PayPeriodStartDate;
payday.PayPeriodEnd = payCalendar.PayPeriodEndDate;
payday.PaymentDate = payCalendar.NextPaymentDate;
payday.HoursWorked = hoursWorked;
payday.SickLeaveAccrual = this.CalculateSickLeaveEntitlement(hoursWorked, sickLeaveEntitlement);
payday.AnnualLeaveAccrual = this.CalculateAnnualLeaveEntitlement(hoursWorked, annualLeaveEntitlement);
payday.LongServiceLeaveAccrual = (user.StartDateCurrentAnnualSalary > tenYearsAgo) ? 0m : this.CalculateLongServiceEntitlement(hoursWorked, longServiceLeaveEntitlement);
payday.SickLeaveAccrualValue = payday.SickLeaveAccrual * hourlyRate;
payday.AnnualLeaveAccrualValue = payday.AnnualLeaveAccrual * hourlyRate;
payday.LongServiceLeaveAccrualValue = payday.LongServiceLeaveAccrual * hourlyRate;
this.Add(payday);
// do calculation on leave balance
// jika leave balance di awal bulan maka lakukan replikasi dr bulan sebelumnya.
// closebalance menjadi opening balance bulan selanjutnya.
LeaveBalance sickLeaveBalance = await this.GetUserLeaveBalance(user.Id, sickLeaveEntitlement, "sickLeave");
if (sickLeaveBalance == null)
{
// sickLeaveBalance = await this.CreateLeaveBalance(user.Id,sickLeaveEntitlement,"sickLeave",payday.PaymentDate);
// sickLeaveBalance.CurrentBalance =+ payday.SickLeaveAccrual ;
// sickLeaveBalance.CurrentBalanceValue += payday.SickLeaveAccrualValue;
throw new Exception($"Sick Leave balance for user: {user.Username} is not found. Please report this as bug");
}
else
{
sickLeaveBalance.CurrentBalance = +payday.SickLeaveAccrual;
sickLeaveBalance.CurrentBalanceValue += payday.SickLeaveAccrualValue;
sickLeaveBalance.LastUpdate = payday.PaymentDate;
}
LeaveBalance annualLeaveBalance = await this.GetUserLeaveBalance(user.Id, annualLeaveEntitlement, "annualLeave");
if (annualLeaveBalance == null)
{
throw new Exception($"Annual Leave balance for user: {user.Username} is not found. Please report this as bug");
}
else
{
annualLeaveBalance.CurrentBalance = +payday.AnnualLeaveAccrual;
annualLeaveBalance.CurrentBalanceValue += payday.AnnualLeaveAccrualValue;
annualLeaveBalance.LastUpdate = payday.PaymentDate;
}
LeaveBalance longServiceLeaveBalance = await this.GetUserLeaveBalance(user.Id, longServiceLeaveEntitlement, "longServiceLeave");
if (longServiceLeaveBalance == null)
{
throw new Exception($"Long Service Leave balance for user: {user.Username} is not found. Please report this as bug");
}
else
{
longServiceLeaveBalance.CurrentBalance = +payday.LongServiceLeaveAccrual;
longServiceLeaveBalance.CurrentBalanceValue += payday.LongServiceLeaveAccrualValue;
longServiceLeaveBalance.LastUpdate = payday.PaymentDate;
}
});
return await this.SaveAll();
}
完整的错误:
失败:Microsoft.EntityFrameworkCore.Update[10000] 保存上下文类型“CRSApp.API.Data.DataContext”的更改时数据库中发生异常。System.InvalidOperationException:在前一个操作完成之前在此上下文上启动了第二个操作。不保证任何实例成员都是线程安全的。在 Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection() 在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IReadOnlyList
1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) System.InvalidOperationException: A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe. at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection() at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IReadOnlyList
Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancelToken) 的 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) 的 1 个条目ToSave, CancellationToken cancelToken) 失败:Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware [ 1] 执行请求时发生未处理的异常。System.InvalidOperationException:在前一个操作完成之前在此上下文上启动了第二个操作。不保证任何实例成员都是线程安全的。在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager 的 Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()。1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at CRSApp.API.Data.PayrollRepository.SaveAll() in E:\CRSApp\crsapp.api\Data\PayrollRepository.cs:line 35 at CRSApp.API.Data.PayrollRepository.ProcessPayCalendar(PayCalendar payCalendar) in E:\CRSApp\crsapp.api\Data\PayrollRepository.cs:line 229 at CRSApp.API.Controllers.Admin.PayrollController.ProcessPayCalendar(PayCalendarParam param) in E:\CRSApp\crsapp.api\Controllers\Admin\PayrollController.cs:line 68 at Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments) at System.Threading.Tasks.ValueTask
1.get_Result() 在 Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync() 在 Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync() 在 Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context) 在Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync() 在 Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter () 在 Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext 上下文) 在 Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state,Boolean& isCompleted) 在 Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync() 在 Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext) 在 Microsoft.AspNetCore.Mvc.InvokeFilterPipelineAsync() 在 Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()。 Authentication.AuthenticationMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke( HttpContext 上下文)RouterMiddleware.Invoke(HttpContext httpContext) 在 Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) ) 在 Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext 上下文)RouterMiddleware.Invoke(HttpContext httpContext) 在 Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) ) 在 Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext 上下文)
仅供参考:我使用 Dotnet Core 2.1.1,如下所述。
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.App" Version="2.1.1"/>
<PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.1.0" PrivateAssets="All"/>
<PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="4.0.1"/>
<PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="2.1.1"/>
<PackageReference Include="MailKit" Version="2.0.6"/>
</ItemGroup>
解决方案
DbContext
不是线程安全的
我认为这ForEach
是你的问题。
users.ForEach(async user =>
{
//....
LeaveBalance sickLeaveBalance = await this.GetUserLeaveBalance(user.Id,});
// .....
});
当您使用async
关键字时,将为每个用户异步调用一个操作,因此您的代码执行将类似于以下代码的执行:
foreach(var user in users){
//without await
//it's an async method
DoSomeThingAsync(user); //you called GetUserLeaveBalance in DoSomeThingAsync
}
正如我猜的那样,GetUserLeaveBalance
正在使用DbContext
,所以你正在DbContext
异步使用,你将面临这样的错误
在前一个操作完成之前,在此上下文上开始了第二个操作...
你需要改变你ForEach
的东西像这样
foreach(var user in users){
await DoSomeThingAsync(user); //you called GetUserLeaveBalance in DoSomeThingAsync
}
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