我得到＆＃34;未达到指定的附加位置条件＆＃34;在我使用CloudAppendBlob.AppendTextAsync实现的Logger组件中。我已经搜索并看到如果你从多个任务使用AppendTextAsync可能会出现问题，但我不会在我的代码中这样做。我使用ConcurrentQueue来记录消息，它是从队列中读取的单个任务，并调用AppendTextAsync。
这是我的代码：
private async Task MessageLogger()
{
string messages = "";
while (true)
{
// Check if a new log file should be created
if (DateTime.UtcNow.Day != _logCreatedUtc.Day)
{
// Create a new log file
await CreateNewLogAsync();
}
if (_messageQueue.Count == 0 && messages.Length == 0)
{
// No messages to write, wait
await Task.Delay(50);
continue;
}
int n = 0;
while ((this._messageQueue.Count > 0) && (n < 50))
{
string message;
if (this._messageQueue.TryDequeue(out message))
{
messages += message;
n++;
}
}
try
{
// Append messages to Azure Blob
await _appendBlob.AppendTextAsync(messages);
messages = "";
}
catch (Microsoft.WindowsAzure.Storage.StorageException se)
when(se.RequestInformation.HttpStatusCode == 404)
{
LogException("StorageException from CloudAppendBlob.AppendTextAsync", se);
// Log file was deleted. Create a new log file
await CreateNewLogAsync();
}
catch (AggregateException ex)
{
LogException("AggregateException from CloudAppendBlob.AppendTextAsync", ex);
StorageException se = ExtractStorageException(ex);
if (se != null && se.RequestInformation.ExtendedErrorInformation != null)
{
if (se.RequestInformation.ExtendedErrorInformation.ErrorCode == "BlockCountExceedsLimit")
// Block count exceeds limit. Create a new log file
await CreateNewLogAsync();
}
}
catch (Exception ex)
{
LogException("Exception from CloudAppendBlob.AppendTextAsync", ex);
await Task.Delay(1000);
}
}
}
这是一个示例日志文件：
19.04.2018 00:00:00.115 - INFO: Logfile created: 2018_04_19/SensorDataProcessor_2018_04_19_0000.log
19.04.2018 00:00:00.116 - INFO: LogLevel is currently set to Information
19.04.2018 00:00:00.136 - INFO: Logfile created: 2018_04_19/SensorDataProcessor_2018_04_19_0000.log
19.04.2018 00:00:00.137 - INFO: LogLevel is currently set to Information
19.04.2018 00:00:00.364 - <<EXCEPTION>>: AggregateException from CloudAppendBlob.AppendTextAsync
19.04.2018 00:00:00.365 - <<EXCEPTION>>: Type =<System.AggregateException> Message =<One or more errors occurred. (One or more errors occurred. (The append position condition specified was not met.))> InnerException.Message=<One or more errors occurred. (The append position condition specified was not met.)>
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.<Dispose>b__8_0()
at Microsoft.WindowsAzure.Storage.Core.Util.CommonUtility.RunWithoutSynchronizationContext(Action actionToRun)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.Dispose(Boolean disposing)
at System.IO.Stream.Close()
at Microsoft.WindowsAzure.Storage.Blob.CloudAppendBlob.<UploadFromStreamAsyncHelper>d__34.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Infrastructure.Logging.AzureBlob.Logger.<MessageLogger>d__24.MoveNext() in /opt/vsts/work/1/s/Infrastructure/Logging/Infrastructure.Logging.AzureBlob/Logger.cs:line 183
19.04.2018 00:00:01.434 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:00.684 Value=259.2 ElapsedTime=566
19.04.2018 00:00:02.348 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:01.688 Value=532.9 ElapsedTime=444
19.04.2018 00:00:05.643 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:04.660 Value=446 ElapsedTime=636
19.04.2018 00:00:06.552 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:05.660 Value=32 ElapsedTime=522
19.04.2018 00:00:09.779 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:08.682 Value=259.2 ElapsedTime=651
19.04.2018 00:00:10.255 - INFO: Processed SensorData: Id=2301002 Timestamp=19.04.2018 00:00:08.976 Value=0 ElapsedTime=604
19.04.2018 00:00:10.841 - INFO: Processed SensorData: Id=2002100 Timestamp=19.04.2018 00:00:09.383 Value=0 ElapsedTime=445
19.04.2018 00:00:10.773 - INFO: Processed SensorData: Id=2002001 Timestamp=19.04.2018 00:00:09.205 Value=1 ElapsedTime=644
19.04.2018 00:00:11.079 - <<EXCEPTION>>: AggregateException from CloudAppendBlob.AppendTextAsync
19.04.2018 00:00:11.082 - <<EXCEPTION>>: Type =<System.AggregateException> Message =<One or more errors occurred. (One or more errors occurred. (The append position condition specified was not met.))> InnerException.Message=<One or more errors occurred. (The append position condition specified was not met.)>
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.<Dispose>b__8_0()
at Microsoft.WindowsAzure.Storage.Core.Util.CommonUtility.RunWithoutSynchronizationContext(Action actionToRun)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.Dispose(Boolean disposing)
at System.IO.Stream.Close()
at Microsoft.WindowsAzure.Storage.Blob.CloudAppendBlob.<UploadFromStreamAsyncHelper>d__34.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Infrastructure.Logging.AzureBlob.Logger.<MessageLogger>d__24.MoveNext() in /opt/vsts/work/1/s/Infrastructure/Logging/Infrastructure.Logging.AzureBlob/Logger.cs:line 183
19.04.2018 00:00:11.479 - INFO: Processed SensorData: Id=2005001 Timestamp=19.04.2018 00:00:09.404 Value=14 ElapsedTime=473
19.04.2018 00:00:11.758 - INFO: Processed SensorData: Id=2006001 Timestamp=19.04.2018 00:00:09.515 Value=15.3 ElapsedTime=677
19.04.2018 00:00:12.059 - INFO: Processed SensorData: Id=1005004 Timestamp=19.04.2018 00:00:09.677 Value=532.3 ElapsedTime=449
19.04.2018 00:00:12.762 - INFO: Processed SensorData: Id=2002102 Timestamp=19.04.2018 00:00:09.558 Value=0 ElapsedTime=561
19.04.2018 00:00:12.714 - INFO: Processed SensorData: Id=2006003 Timestamp=19.04.2018 00:00:09.517 Value=0 ElapsedTime=672
19.04.2018 00:00:13.168 - <<EXCEPTION>>: AggregateException from CloudAppendBlob.AppendTextAsync
19.04.2018 00:00:13.171 - <<EXCEPTION>>: Type =<System.AggregateException> Message =<One or more errors occurred. (One or more errors occurred. (The append position condition specified was not met.))> InnerException.Message=<One or more errors occurred. (The append position condition specified was not met.)>
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.<Dispose>b__8_0()
at Microsoft.WindowsAzure.Storage.Core.Util.CommonUtility.RunWithoutSynchronizationContext(Action actionToRun)
at Microsoft.WindowsAzure.Storage.Blob.BlobWriteStream.Dispose(Boolean disposing)
at System.IO.Stream.Close()
at Microsoft.WindowsAzure.Storage.Blob.CloudAppendBlob.<UploadFromStreamAsyncHelper>d__34.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Infrastructure.Logging.AzureBlob.Logger.<MessageLogger>d__24.MoveNext() in /opt/vsts/work/1/s/Infrastructure/Logging/Infrastructure.Logging.AzureBlob/Logger.cs:line 183
19.04.2018 00:00:13.381 - INFO: Processed SensorData: Id=2003001 Timestamp=19.04.2018 00:00:09.663 Value=1.1 ElapsedTime=483
19.04.2018 00:00:13.749 - INFO: Processed SensorData: Id=2003100 Timestamp=19.04.2018 00:00:09.779 Value=0 ElapsedTime=761
获得此异常的原因是什么？
如何进一步排查？
答案 0 :(得分：0)
CloudAppendBlob.AppendTextAsync()的文档标题提及：
此API应严格用于单个编写器方案，因为API在内部使用append-offset条件头来避免在多个编写器方案中不起作用的重复块。
如果您确实需要支持排序不重要的多作者场景，我建议您使用CloudAppendBlob.AppendBlockAsync()。