WCF 可靠性问题

Question

试图测试我的 wcf 服务的可靠性。我正在从客户端循环调用 wcf 服务。 wcf 休息服务（webhttpbinding）做一些数据处理和插入 记录到数据库中。整个操作在一个事务中完成。

如果我将 InstanceContextMode 设置为 PerCall，我发现在大约 60 条消息（从循环内调用服务的 60 倍）中只有 40 条消息通过数据库。没有错误没有例外。消息刚刚被丢弃。

如果我将 InstanceContextMode 设置为 Single，那么我会看到所有消息都到达了 db。 InstanceContextMode.Percall 是有损的预期行为吗？另外，我没有设置并发。任何澄清都会非常有帮助。添加了代码。使用 MySQL 作为数据库...

编辑我的错 - 我刚刚注意到服务器端出现异常 - {"Deadlock found when trying to get lock; try restarting transaction"}

这是因为在进行事务时，对同一记录调用了另一个事务。如果它失败一次，则通过重新启动事务来修复它。

服务

    [WebInvoke(UriTemplate = "employee", Method = "POST")]
    public long AddNewEmployee(EmployeeEntity newEmployee)
    {
        EmployeeRepository eRep = new EmployeeRepository();
        return eRep.AddNewEmployee(newEventEntity);                     
    }

存储库类构造函数初始化对象上下文

    public EmployeeRepository()
    {
        bd = new EmployeeEntity();
    }

代码 - 服务调用

    //bd is the object context 
    //there are two tables 
    internal long AddNewEmployee(EmployeeEntity newEmployee)
    {
        bool tSuccess = false;
        using (TransactionScope transaction = new TransactionScope())
        {
            try
            {
                //get existing employees
                var existingEmployees = from employee
                                        in bd.employees select employee;


                List<employee> returnedEmployees = new List<employee>();                    

                //Do some processing 
                returnedEmployees = DoSomeprocessing(existingEmployees);

                //Insert returned employees as updates
                foreach (employee e in returnedEmployees)
                {
                    bd.employees.AddObject(e);
                }

                bd.SaveChanges();
                returnedEmployees.Clear();

                //add to second table 
                bd.otherdetails.AddObject(newEmployee);
                bd.SaveChanges();


                //Transaction Complete                        
                transaction.Complete();
                tSuccess = true;

            }
            catch (Exception e)
            {
                //return something meaningful 
                return -1;                    
            }
        }

        if (tSuccess)
        {
            //End Transaction
            bd.AcceptAllChanges();
            return 200;
        }            
        else
        {
           return -1;
        }

    }

客户端只是循环调用服务

Answer 1

我强烈建议为任何 WCF 添加全局异常处理。它帮助我节省了许多小时的调试时间，并且可以捕获任何未处理的异常。它比 ASP.NET 中的 global.ascx 涉及更多一点

第 1 步 - 实施 IerroHander 和 IServiceBehavior

注意 HandleError 内部我正在使用 Enterprise Library 来处理异常。您也可以在此处使用您的自定义实现。

 public class ErrorHandler : IErrorHandler, IServiceBehavior
        {        
            public bool HandleError(Exception error)
            {
                // Returning true indicates you performed your behavior.
                return true;
            }


            public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
            {            
                // Log Exception

                ExceptionPolicy.HandleException(error, "ExceptionPolicy");

                // Shield the unknown exception
                FaultException faultException = new FaultException(
                    "Server error encountered. All details have been logged.");
                MessageFault messageFault = faultException.CreateMessageFault();

                fault = Message.CreateMessage(version, messageFault, faultException.Action);
            }

            private IErrorHandler errorHandler = null;

            public ErrorHandler()
            {

            }

            public ErrorHandler(IErrorHandler errorHandler)
            {
                this.errorHandler = errorHandler;
            }

            public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
            {
                foreach (ChannelDispatcherBase cdb in serviceHostBase.ChannelDispatchers)
                {
                    ChannelDispatcher cd = cdb as ChannelDispatcher;

                    if (cd != null)
                    {
                        cd.ErrorHandlers.Add(new ErrorHandler());
                    }
                }
            }

            public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
            {
                foreach (ChannelDispatcherBase cdb in serviceHostBase.ChannelDispatchers)
                {
                    ChannelDispatcher cd = cdb as ChannelDispatcher;

                    if (cd != null)
                    {
                        cd.ErrorHandlers.Add(new ErrorHandler());
                    }
                }
            }

            public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
            {

            }
        }

    }

第 2 步 - 创建错误元素

public class ErrorHandlerElement : BehaviorExtensionElement
    {
        protected override object CreateBehavior()
        {
            return new ErrorHandler();
        }

        public override Type BehaviorType
        {
            get
            {
                return typeof(ErrorHandler);
            }
        }
    }

第 3 步 - 将元素添加到 web.config

<serviceBehaviors>
        <behavior>                              
          <ErrorHandler />
        </behavior>
      </serviceBehaviors>