Question

我正在使用.NET客户端API：IUploadProgress progress = insertMediaUpload.Upload（）将csv上传到BigQuery。基本上我所做的是：

1.提交上传工作，
2.获得工作状态（待定，运行，完成......）
3.如果BigQuery提供任何错误，则打印它们并抛出异常以便进一步处理。

下面的代码并没有完全符合我的要求，我希望有人可以帮助我改进它。

具体来说，发生了几个奇怪的代码行为：
1.即使在故意制作失败的同一个CSV上运行相同的代码，在UploadOnResponseReceived（）中解析出的BQ错误消息也会在某些调用中打印出来，但在其他调用中则不会打印出来。为什么呢？
2. IUploadProgress值似乎与UploadOnResponseReceived（）行为相关：如果我在UploadOnResponseReceived中什么都不做，那么progress.status将始终为'Completed'，如果UploadOnResponseReceived抛出异常，则progress.status将失败。
3.当progress.status失败时，无法从UploadOnResponseReceived中获取异常。我确实需要得到例外，我该怎么办？

 public bool ExecuteUploadJobToTable(string dataset, string tableId, string filePath, TableSchema schema, string createDisposition, char delimiter)
    {

        TableReference destTable = new TableReference { ProjectId = _account.ProjectId, DatasetId = dataset, TableId = tableId };

        JobConfigurationLoad configLoad = new JobConfigurationLoad 
        {
            Schema = schema,
            DestinationTable = destTable,
            Encoding = "ISO-8859-1",
            CreateDisposition = "CREATE_IF_NEEDED",
            WriteDisposition = createDisposition,
            FieldDelimiter = delimiter.ToString(),
            AllowJaggedRows = true,
            SourceFormat = "CSV"
        };

        JobConfiguration config = new JobConfiguration {Load = configLoad};

        Job job = new Job {Configuration = config};

        //set job reference (mainly job id)
        JobReference jobRef = new JobReference
        {
            JobId = GenerateJobID("Upload"),
            ProjectId = _account.ProjectId
        };
        job.JobReference = jobRef;

        bool isSuccess = true;
        using (var fileStream = new FileStream(filePath, FileMode.Open))
        {
            JobsResource.InsertMediaUpload insertMediaUpload = new JobsResource.InsertMediaUpload(BigQueryService, job, job.JobReference.ProjectId, stream: fileStream, contentType: "application/octet-stream");
            insertMediaUpload.ProgressChanged += UploadOnProgressChanged;
            insertMediaUpload.ResponseReceived += UploadOnResponseReceived;

            Console.WriteLine(string.Format("start {0}",jobRef.JobId));
            IUploadProgress progress = insertMediaUpload.Upload();
            if (progress.Status.ToString().Contains("Fail"))
            {
                isSuccess = false;
            }
        }
        Console.WriteLine(isSuccess);
        return isSuccess;
    }

    private void UploadOnProgressChanged(IUploadProgress process)
    {
        Console.WriteLine(process.Status + " " + process.BytesSent);
    }

    //thowring an exception will make IUploadProgress "Failed", otherwise, IUploadProgress will be "Completed"
    private void UploadOnResponseReceived(Job job)
    {
        try
        {
            job = PollUntilJobDone(job.JobReference, 5);
        }
        catch(Exception e)
        {
            Console.WriteLine("Unexcepted unretryable exception happens when poll job status");
            throw new BigQueryException("Unexcepted unretryable exception happens when poll job status",e);
        }

        StringBuilder errorMessageBuilder = new StringBuilder();
        ErrorProto fatalError = job.Status.ErrorResult;
        IList<ErrorProto> errors = job.Status.Errors;
        if (fatalError != null)
        {
            errorMessageBuilder.AppendLine("Job failed while writing to Bigquery. " + fatalError.Reason + ": " + fatalError.Message +
                      " at " + fatalError.Location);
        }
        if (errors != null)
        {
            foreach (ErrorProto error in errors)
            {
                errorMessageBuilder.AppendLine("Error: [REASON] " + error.Reason + " [MESSAGE] " + error.Message +
                                               " [LOCATION] " + error.Location);
            }

        }
        if (errorMessageBuilder.Length>0)//fatalError != null || errors != null  
        {
            Console.WriteLine(errorMessageBuilder.ToString());
            throw new BigQueryException(errorMessageBuilder.ToString());
        }
        Console.WriteLine("upload should be successful");
    }

    private Job PollUntilJobDone(JobReference jobReference, int pauseSeconds)
    {
        int backoff = 1000;//backoff starts from 1 sec + random

        for(int i = 0; i < 10; i++)
        {
            try
            {
                var pollJob = BigQueryService.Jobs.Get(jobReference.ProjectId, jobReference.JobId).Execute();
                Console.WriteLine(jobReference.JobId + ": " + pollJob.Status.State);
                if (pollJob.Status.State.Equals("DONE"))
                {
                    return pollJob;
                }
                // Pause execution for pauseSeconds before polling job status again,
                // to reduce unnecessary calls to the BigQuery API and lower overall
                // application bandwidth.
                Thread.Sleep(pauseSeconds * 1000);
            }
            catch (Exception e)
            {
                BigQueryException exception = new BigQueryException(e.Message,e);
                if (exception.IsTemporary)
                {
                    int sleep = backoff + Random.Next(1000);
                    Console.WriteLine("pollUntilJobDone job execute failed. Sleeping {0} ms before retry", sleep);
                    Thread.Sleep(sleep);
                }
                else
                {
                    throw;
                }
            }
            backoff *= 2;
        }
        return null;
    }

Answer 1

关于你的＆＃34;如何捕捉异常＆＃34;问题，似乎回调在另一个线程上异步发生。如果你抛出一个异常，它会被调用回调的任何框架捕获。

搜索类似问题我发现这些答案可能会对您有所帮助：Catching an exception thrown in an asynchronous callback，并且这个答案显示了如何从后台线程中收到的上传进度更新另一个线程中的UI：Tracking upload progress of WebClient < / p>

.NET InsertMediaUpload将CSV上传到BigQuery时出现的奇怪问题

1 个答案: