C# 在Azure中锁定模拟
我需要在Azure web实例中实现一些线程结果逻辑。 我有一些这样的代码:C# 在Azure中锁定模拟,c#,asp.net,multithreading,azure,azure-web-roles,C#,Asp.net,Multithreading,Azure,Azure Web Roles,我需要在Azure web实例中实现一些线程结果逻辑。 我有一些这样的代码: lock (_bookingLock) { // Check for a free time bool isTimeFree = _scheduleService.IsTimeFree(dateTimeGuidId); //* race condition here if (isTimeFree) { // Make a booking. So this time
lock (_bookingLock)
{
// Check for a free time
bool isTimeFree = _scheduleService.IsTimeFree(dateTimeGuidId);
//* race condition here
if (isTimeFree)
{
// Make a booking. So this time is busy
newBookingId = _paymentService.CreateBooking(dateTimeGuidId).ToString();
}
}
但是我不能在多实例环境中使用
lock
,也不能忽略lock,因为*
中存在竞争条件。这里最好的方法是什么?我强烈建议通过一系列消息对此进行建模。您可以通过Azure服务总线发送消息(命令)来创建预订。只有一个消费者会处理该消息,您不需要“锁定”。此外,还可以扩展到多个使用者,以便可以同时处理多个命令。事件还可用于通知消费者状态的变化(如预订已创建或更新),并执行他们需要执行的操作。我强烈建议通过一系列消息对此进行建模。您可以通过Azure服务总线发送消息(命令)来创建预订。只有一个消费者会处理该消息,您不需要“锁定”。此外,还可以扩展到多个使用者,以便可以同时处理多个命令。事件还可以用于通知消费者状态的更改(如创建或更新了预订),并执行他们需要执行的操作。我决定使用blob租约。我升级到使用Azure存储客户端版本2或3,并编写了一个附加方法。以下是完整代码:
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.WindowsAzure.Storage.Shared.Protocol;
using Microsoft.WindowsAzure.Storage.Blob.Protocol;
using System.Configuration;
namespace TerminalManager.Domain.Foundation.BlobLeases
{
public class AutoRenewLease : IDisposable
{
public bool HasLease { get { return leaseId != null; } }
AccessCondition _accessCondition;
private CloudBlockBlob blob;
private string leaseId;
private Thread renewalThread;
private bool disposed = false;
public static void DoOnce(CloudBlockBlob blob, Action action) { DoOnce(blob, action, TimeSpan.FromSeconds(5)); }
public static void DoOnce(CloudBlockBlob blob, Action action, TimeSpan pollingFrequency)
{
// blob.Exists has the side effect of calling blob.FetchAttributes, which populates the metadata collection
while (!blob.Exists() || blob.Metadata["progress"] != "done")
{
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
action();
blob.Metadata["progress"] = "done";
AccessCondition ac = new AccessCondition();
ac.LeaseId = arl.leaseId;
blob.SetMetadata(ac);
}
else
{
Thread.Sleep(pollingFrequency);
}
}
}
}
/// <summary>
/// Выполнить последовательно
/// </summary>
/// <param name="lockBlobName">имя блоба - просто буквы</param>
/// <param name="action"></param>
/// <param name="cnStrName">из конфига</param>
/// <param name="containerName">из конфига</param>
/// <param name="pollingFrequency"></param>
public static void DoConsequence(string lockBlobName, Action action,
string cnStrName = "StorageConnectionString",
string containerName = "leasesContainer", TimeSpan? pollingFrequency = null)
{
//http://www.windowsazure.com/en-us/develop/net/how-to-guides/blob-storage/
// Формат пути к блобу
//http://<storage account>.blob.core.windows.net/<container>/<blob>
// Блобовский аккаунт
var account = CloudStorageAccount.Parse(ConfigurationManager.ConnectionStrings[cnStrName].ConnectionString); //CloudStorageAccount.Parse("UseDevelopmentStorage=true"); // Не работает на SDK 2.2 // or your real connection string
var blobs = account.CreateCloudBlobClient();
// Контейнер - типа папки
var container = blobs
.GetContainerReference(ConfigurationManager.AppSettings[containerName]);
container.CreateIfNotExists();
var blob = container.GetBlockBlobReference(lockBlobName);
bool jobDone = false;
while (!jobDone)
{
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
// Some Sync Work here
action();
jobDone = true;
}
else
{
Thread.Sleep(pollingFrequency ?? TimeSpan.FromMilliseconds(300));
}
}
}
}
public static void DoEvery(CloudBlockBlob blob, TimeSpan interval, Action action)
{
while (true)
{
var lastPerformed = DateTimeOffset.MinValue;
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
blob.FetchAttributes();
DateTimeOffset.TryParseExact(blob.Metadata["lastPerformed"], "R", CultureInfo.CurrentCulture, DateTimeStyles.AdjustToUniversal, out lastPerformed);
if (DateTimeOffset.UtcNow >= lastPerformed + interval)
{
action();
lastPerformed = DateTimeOffset.UtcNow;
blob.Metadata["lastPerformed"] = lastPerformed.ToString("R");
AccessCondition ac = new AccessCondition();
ac.LeaseId = arl.leaseId;
blob.SetMetadata(ac);
}
}
}
var timeLeft = (lastPerformed + interval) - DateTimeOffset.UtcNow;
var minimum = TimeSpan.FromSeconds(5); // so we're not polling the leased blob too fast
Thread.Sleep(
timeLeft > minimum
? timeLeft
: minimum);
}
}
public AutoRenewLease(CloudBlockBlob blob)
{
this.blob = blob;
blob.Container.CreateIfNotExists();
try
{
if (!blob.Exists())
{
blob.UploadFromByteArray(new byte[0], 0, 0, AccessCondition.GenerateIfNoneMatchCondition("*"));// new BlobRequestOptions { AccessCondition = AccessCondition.IfNoneMatch("*") });
}
}
catch (StorageException e)
{
if (e.RequestInformation.HttpStatusCode != (int)HttpStatusCode.PreconditionFailed // 412 from trying to modify a blob that's leased
&& e.RequestInformation.ExtendedErrorInformation.ErrorCode != BlobErrorCodeStrings.BlobAlreadyExists
)
{
throw;
}
}
try
{
leaseId = blob.AcquireLease(TimeSpan.FromSeconds(60), null);
_accessCondition = new AccessCondition { LeaseId = leaseId };
}
catch (Exception)
{
Trace.WriteLine("==========> Lease rejected! <==========");
}
if (HasLease)
{
renewalThread = new Thread(() =>
{
while (true)
{
Thread.Sleep(TimeSpan.FromSeconds(40));
var ac = new AccessCondition();
ac.LeaseId = leaseId;
blob.RenewLease(ac);//.RenewLease(leaseId);
}
});
renewalThread.Start();
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!disposed)
{
if (disposing)
{
if (renewalThread != null)
{
renewalThread.Abort();
blob.ReleaseLease(_accessCondition);
renewalThread = null;
}
}
disposed = true;
}
}
~AutoRenewLease()
{
Dispose(false);
}
}
}
我决定使用blob租约。我升级到使用Azure存储客户端版本2或3,并编写了一个附加方法。以下是完整代码:
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.WindowsAzure.Storage.Shared.Protocol;
using Microsoft.WindowsAzure.Storage.Blob.Protocol;
using System.Configuration;
namespace TerminalManager.Domain.Foundation.BlobLeases
{
public class AutoRenewLease : IDisposable
{
public bool HasLease { get { return leaseId != null; } }
AccessCondition _accessCondition;
private CloudBlockBlob blob;
private string leaseId;
private Thread renewalThread;
private bool disposed = false;
public static void DoOnce(CloudBlockBlob blob, Action action) { DoOnce(blob, action, TimeSpan.FromSeconds(5)); }
public static void DoOnce(CloudBlockBlob blob, Action action, TimeSpan pollingFrequency)
{
// blob.Exists has the side effect of calling blob.FetchAttributes, which populates the metadata collection
while (!blob.Exists() || blob.Metadata["progress"] != "done")
{
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
action();
blob.Metadata["progress"] = "done";
AccessCondition ac = new AccessCondition();
ac.LeaseId = arl.leaseId;
blob.SetMetadata(ac);
}
else
{
Thread.Sleep(pollingFrequency);
}
}
}
}
/// <summary>
/// Выполнить последовательно
/// </summary>
/// <param name="lockBlobName">имя блоба - просто буквы</param>
/// <param name="action"></param>
/// <param name="cnStrName">из конфига</param>
/// <param name="containerName">из конфига</param>
/// <param name="pollingFrequency"></param>
public static void DoConsequence(string lockBlobName, Action action,
string cnStrName = "StorageConnectionString",
string containerName = "leasesContainer", TimeSpan? pollingFrequency = null)
{
//http://www.windowsazure.com/en-us/develop/net/how-to-guides/blob-storage/
// Формат пути к блобу
//http://<storage account>.blob.core.windows.net/<container>/<blob>
// Блобовский аккаунт
var account = CloudStorageAccount.Parse(ConfigurationManager.ConnectionStrings[cnStrName].ConnectionString); //CloudStorageAccount.Parse("UseDevelopmentStorage=true"); // Не работает на SDK 2.2 // or your real connection string
var blobs = account.CreateCloudBlobClient();
// Контейнер - типа папки
var container = blobs
.GetContainerReference(ConfigurationManager.AppSettings[containerName]);
container.CreateIfNotExists();
var blob = container.GetBlockBlobReference(lockBlobName);
bool jobDone = false;
while (!jobDone)
{
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
// Some Sync Work here
action();
jobDone = true;
}
else
{
Thread.Sleep(pollingFrequency ?? TimeSpan.FromMilliseconds(300));
}
}
}
}
public static void DoEvery(CloudBlockBlob blob, TimeSpan interval, Action action)
{
while (true)
{
var lastPerformed = DateTimeOffset.MinValue;
using (var arl = new AutoRenewLease(blob))
{
if (arl.HasLease)
{
blob.FetchAttributes();
DateTimeOffset.TryParseExact(blob.Metadata["lastPerformed"], "R", CultureInfo.CurrentCulture, DateTimeStyles.AdjustToUniversal, out lastPerformed);
if (DateTimeOffset.UtcNow >= lastPerformed + interval)
{
action();
lastPerformed = DateTimeOffset.UtcNow;
blob.Metadata["lastPerformed"] = lastPerformed.ToString("R");
AccessCondition ac = new AccessCondition();
ac.LeaseId = arl.leaseId;
blob.SetMetadata(ac);
}
}
}
var timeLeft = (lastPerformed + interval) - DateTimeOffset.UtcNow;
var minimum = TimeSpan.FromSeconds(5); // so we're not polling the leased blob too fast
Thread.Sleep(
timeLeft > minimum
? timeLeft
: minimum);
}
}
public AutoRenewLease(CloudBlockBlob blob)
{
this.blob = blob;
blob.Container.CreateIfNotExists();
try
{
if (!blob.Exists())
{
blob.UploadFromByteArray(new byte[0], 0, 0, AccessCondition.GenerateIfNoneMatchCondition("*"));// new BlobRequestOptions { AccessCondition = AccessCondition.IfNoneMatch("*") });
}
}
catch (StorageException e)
{
if (e.RequestInformation.HttpStatusCode != (int)HttpStatusCode.PreconditionFailed // 412 from trying to modify a blob that's leased
&& e.RequestInformation.ExtendedErrorInformation.ErrorCode != BlobErrorCodeStrings.BlobAlreadyExists
)
{
throw;
}
}
try
{
leaseId = blob.AcquireLease(TimeSpan.FromSeconds(60), null);
_accessCondition = new AccessCondition { LeaseId = leaseId };
}
catch (Exception)
{
Trace.WriteLine("==========> Lease rejected! <==========");
}
if (HasLease)
{
renewalThread = new Thread(() =>
{
while (true)
{
Thread.Sleep(TimeSpan.FromSeconds(40));
var ac = new AccessCondition();
ac.LeaseId = leaseId;
blob.RenewLease(ac);//.RenewLease(leaseId);
}
});
renewalThread.Start();
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!disposed)
{
if (disposing)
{
if (renewalThread != null)
{
renewalThread.Abort();
blob.ReleaseLease(_accessCondition);
renewalThread = null;
}
}
disposed = true;
}
}
~AutoRenewLease()
{
Dispose(false);
}
}
}
您是否与单个实体一起工作?换句话说,您是否通过将同一实体的属性更改为booked(如果可用)来更新该实体?否,我有一个包含空闲时间项目的表。我有一张预定的桌子。我检查一段时间是否没有预订,那么这段时间是免费的,可以预订。但是如果两个或更多的用户同时尝试预订空闲时间,那么他们将收到两次预订!在这种情况下,只有一个用户必须收到预订,另一个用户必须收到一条消息,表示此时正忙。大多数数据库都有事务,或者至少有原子检查和更新操作。围绕“azure事务”做一些研究我有azure SQL DB。我读过类似情况下的表锁定(整个表),但这是非常昂贵的操作。我想从数据层进行抽象,并在业务层同步我的操作。悲观并发控制(您正在尝试执行)或乐观并发控制。试着乐观一点,这可能更容易。你是在和一个实体合作吗?换句话说,您是否通过将同一实体的属性更改为booked(如果可用)来更新该实体?否,我有一个包含空闲时间项目的表。我有一张预定的桌子。我检查一段时间是否没有预订,那么这段时间是免费的,可以预订。但是如果两个或更多的用户同时尝试预订空闲时间,那么他们将收到两次预订!在这种情况下,只有一个用户必须收到预订,另一个用户必须收到一条消息,表示此时正忙。大多数数据库都有事务,或者至少有原子检查和更新操作。围绕“azure事务”做一些研究我有azure SQL DB。我读过类似情况下的表锁定(整个表),但这是非常昂贵的操作。我想从数据层进行抽象,并在业务层同步我的操作。悲观并发控制(您正在尝试执行)或乐观并发控制。试着乐观一点,这可能更容易,但这并不能保证有效。所有这些实际上都是为了保证对blob的租用访问。对于更广泛的问题,请阅读以下内容:这并不能保证有效。所有这些实际上都是为了保证对blob的租用访问。要想了解更广泛的问题,请阅读以下内容:并非如此。正确是要付出代价的。这也是为什么存在“最多一次”交付保证的服务总线队列的原因。正确是要付出代价的。这也是存在“最多一次”交付保证的服务总线队列的原因。