Async/Await调用在web API中受阻

Question

我们有一个运行在.net4.6.1上的web API应用程序。我们已经多次试图找出它陷入僵局的根本原因，但都失败了。下面是代码片段。我们每1分钟访问一次此API端点。它将一次从数据库中挑选300个事务进行处理。我们已经观察到，当数据库中没有要处理的文件时，它会被卡住。但不确定。如果有人能帮助我们，那会很有帮助

public class TaxEngineIntegratorController : ApiController
{
public async Task Get(int id)
{
try
{
await MainFileMethod();

}
catch (Exception Ex)
{
SerilogMethods.LogError(log, Ex, "Get");
}
}
public async Task MainFileMethod()
{
List<FileTransaction> lstFTtoLock = new List<FileTransaction>();
try
{
List<int> lstStatusIds = new List<int>();
lstStatusIds.Add(objStatusManager.GetStatusIdbyName(Status.ConversionToXmlSucceded));
lstStatusIds.Add(objStatusManager.GetStatusIdbyName(Status.Reprocess));
//Getting the serviceURL of TRTaxEngine
string seriviceURL = objConfigManager.GetConfigurationdbyKey(ConfigurationList.TRTaxEngineURL);
//Getting the output path for the file to be placed after processing
string outputfilePath = objConfigManager.GetConfigurationdbyKey(ConfigurationList.TRTaxOutputXMLFolder);
FileMasterManager objFileMasterManager = new FileMasterManager();
TRTaxXMLOperations objxmlresp = new TRTaxXMLOperations();
//Getting all the files list for proccessing from the DB
List<FileTransaction> lstFiletoProcess = await objTransManager.GetFileListforProcessingAsync(lstStatusIds, true);
lstFTtoLock = lstFiletoProcess;

if (lstFiletoProcess.Count == 0)
return;


if (lstFiletoProcess.Count > 0)
{
var tasks = new List<Task<string>>();
using (HttpClient httpClnt = new HttpClient())
{
httpClnt.Timeout = TimeSpan.FromMilliseconds(-1);

foreach (FileTransaction item in lstFiletoProcess)
{

TRXMLResponseModel objRespModel = new TRXMLResponseModel();
objRespModel.strxmlResponse = string.Empty;
string fullFileName = item.FilePath + item.ConvertedName;
objRespModel.outputFilename = outputfilePath + item.ConvertedName;
FileMaster fileMaster = objFileMasterManager.GetById(item.FileId);
//Proccessing the file and getting the output filedata                        
Task<string> t = objxmlresp.GetXMLResponse(seriviceURL, fullFileName, fileMaster.CountryId.GetValueOrDefault(), httpClnt, objFileOperation, objRespModel.outputFilename, item);
tasks.Add(t);
objRespModel.strxmlResponse = await t;

}
var result = await Task.WhenAll(tasks);
}

SerilogMethods.LogCustomException(log, "Http Client Destroyed in Tax Engine", "GetXMLResponse");
}
}
catch (Exception Ex)
{
if (lstFTtoLock != null && lstFTtoLock.Count > 0)
{
objTransManager.UpdateFileTransactionIsPickedtoFalse(lstFTtoLock);
}
throw Ex;
}
}

}

//从DB 获取所有文件列表以进行处理

public async Task<List<FileTransaction>> GetFileListforProcessingAsync(List<int> lstStatusList, bool IsActive)
{
try
{
List<FileTransaction> lstFTList = new List<FileTransaction>();

using (SUTBACDEVContext db = new SUTBACDEVContext())
{
//DataTable dtFileTransactions = GetFileTransactionListAsync(lstStatusList, IsActive);
string connectionString = db.Database.GetDbConnection().ConnectionString;
var conn = new SqlConnection(connectionString);
string query = @"[SUTGITA].[GetFileListforProcessing]";
using (var sqlAdpt = new SqlDataAdapter(query, conn))
{
sqlAdpt.SelectCommand.CommandType = CommandType.StoredProcedure;
sqlAdpt.SelectCommand.Parameters.AddWithValue("@StatusId", string.Join(",", lstStatusList.Select(n => n.ToString()).ToArray()));
sqlAdpt.SelectCommand.Parameters.AddWithValue("@IsActive", IsActive);
sqlAdpt.SelectCommand.CommandTimeout = 60000;
DataTable dtFileTransactions = new DataTable();
sqlAdpt.Fill(dtFileTransactions);

if (dtFileTransactions != null && dtFileTransactions.Rows.Count > 0)
{
IEnumerable<long> ids = dtFileTransactions.AsEnumerable().ToList().Select(p => p["id"]).ToList().OfType<long>();
lstFTList = await db.FileTransaction.Include(x => x.File.Country).Where(x => ids.Contains(x.Id)).OrderBy(x => x.Id).ToListAsync();
}                        
}

}
return lstFTList;
}
catch (Exception ex)
{
throw ex;
}
}

public async Task<string> GetXMLResponse(string baseUrl, string fullFileName, int countryId, HttpClient client, FileOperations objFileOperation, string outputfilePath, FileTransaction item)
{
try
{
var fileData = new StringBuilder(objFileOperation.ReadFile(fullFileName));
using (HttpContent content = new StringContent(TransformToSOAPXml(fileData, countryId), Encoding.UTF8, "text/xml"))
{
using (HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, baseUrl))
{
request.Headers.Add("SOAPAction", "");
request.Content = content;
using (HttpResponseMessage response = await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead))
{
response.EnsureSuccessStatusCode();
if (response.IsSuccessStatusCode)
{
using (Stream streamToReadFrom = await response.Content.ReadAsStreamAsync())
{
using (Stream streamToWriteTo = File.Open(outputfilePath, FileMode.Create))
{
await streamToReadFrom.CopyToAsync(streamToWriteTo);
}
}
var transactionEntry = new FileTransaction
{
FileId = item.FileId,
FilePath = outputfilePath,
ConvertedName = item.ConvertedName,
ActionedBy = Process.Process3,
TimeStamp = DateTime.UtcNow,
StatusId = objStatusManager.GetStatusIdbyName(Status.OutputXmlReceived),
IsActive = true,
CreatedBy = Others.Scheduler,
CreatedOn = DateTime.UtcNow,
ModifiedBy = Others.Scheduler,
ModifiedOn = DateTime.UtcNow
};
//Inserting the new record and Updating isActive filed of previous record in Tranasaction table(Calling updateDataonTRSuccess method of TRTaxXMLOperations class)
await updateDataonTRSuccessAsync(item, transactionEntry);
return "Success";
}
else
{
SerilogMethods.LogCustomException(log, "Error occured in Tax Engine", "GetXMLResponse");
//Log the SOAP response when the SOAP fails with an error message
if (response.Content != null)
{
throw new Exception(await response.Content.ReadAsStringAsync());
}
return null;
}
}
}
}
}
catch (Exception ex)
{
SerilogMethods.LogError(log, ex, "GetXMLResponse");
return null;
}
}

我做了以下更改，使其适用于这种特定的方法。删除此行：objRespModel.strxmlResponse=等待t；并将configurewait(false(添加到此行：List lstFiletoProcess=await objTransManager.GetFileListforProcessingAsync(lstStatusId，true(.configureawait(false(；以下是工作代码

public async Task MainFileMethod()
{
List<FileTransaction> lstFTtoLock = new List<FileTransaction>();
try
{
List<int> lstStatusIds = new List<int>();
lstStatusIds.Add(objStatusManager.GetStatusIdbyName(Status.ConversionToXmlSucceded));
lstStatusIds.Add(objStatusManager.GetStatusIdbyName(Status.Reprocess));
//Getting the serviceURL of TRTaxEngine
string seriviceURL = objConfigManager.GetConfigurationdbyKey(ConfigurationList.TRTaxEngineURL);
//Getting the output path for the file to be placed after processing
string outputfilePath = objConfigManager.GetConfigurationdbyKey(ConfigurationList.TRTaxOutputXMLFolder);
FileMasterManager objFileMasterManager = new FileMasterManager();
TRTaxXMLOperations objxmlresp = new TRTaxXMLOperations();
//Getting all the files list for proccessing from the DB
List<FileTransaction> lstFiletoProcess = await objTransManager.GetFileListforProcessingAsync(lstStatusIds, true).ConfigureAwait(false);
lstFTtoLock = lstFiletoProcess;

if (lstFiletoProcess.Count == 0)
return;

if (lstFiletoProcess.Count > 0)
{
var tasks = new List<Task<string>>();
using (HttpClient httpClnt = new HttpClient())
{
httpClnt.Timeout = TimeSpan.FromMilliseconds(-1);
//Getting the files for processing 

foreach (FileTransaction item in lstFiletoProcess)
{
TRXMLResponseModel objRespModel = new TRXMLResponseModel();
objRespModel.strxmlResponse = string.Empty;
string fullFileName = item.FilePath + item.ConvertedName;
objRespModel.outputFilename = outputfilePath + item.ConvertedName;
FileMaster fileMaster = objFileMasterManager.GetById(item.FileId);
//Proccessing the file and getting the output filedata                        
Task<string> t = objxmlresp.GetXMLResponse(seriviceURL, fullFileName, fileMaster.CountryId.GetValueOrDefault(), httpClnt, objFileOperation, objRespModel.outputFilename, item, objTransManager);
tasks.Add(t);
//objRespModel.strxmlResponse = await t;

}
var result = await Task.WhenAll(tasks);
}                 
}
}
catch (Exception Ex)
{
if (lstFTtoLock != null && lstFTtoLock.Count > 0)
{
objTransManager.UpdateFileTransactionIsPickedtoFalse(lstFTtoLock);
}
throw Ex;
}
}

Answer 1

我的建议：

方法"；获取(int id("有些令人困惑。首先；id"；而且它什么也不回，所以它不是一个"；获取"方法它基本上是要求所有具有状态"的交易；Status。ConversionToXmlSuccessed"&quot；Status.Reprocess"；并且是活动的以通过"；objxml响应。GetXMLResponse"；方法你不必等待；MainFileMethod(("在"；获取(int id("只需返回任务或返回Ok((；并允许所有过程在后台进行。你可以尝试减少"；sqlAdpt.SelectCommand.CommandTimeout=60000&"；。