c# – azure webjob因未处理的异常而停止：503服务器不可用

这是我在webjob日志中看到的异常(显示webjob sdk计时器中发生错误)：

04/18/2015 11:10:52 > 2d2f34: ERR ] 
[04/18/2015 11:10:52 > 2d2f34: ERR ] Unhandled Exception: Microsoft.WindowsAzure.Storage.StorageException: The remote server returned an error: (503) Server Unavailable. ---> System.Net.WebException: The remote server returned an error: (503) Server Unavailable.
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Shared.Protocol.HttpResponseParsers.ProcessExpectedStatusCodeNoException[T](HttpStatusCode expectedStatusCode,HttpStatusCode actualStatusCode,T retVal,StorageCommandBase`1 cmd,Exception ex)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Queue.CloudQueue.<ExistsImpl>b__1d(RESTCommand`1 cmd,HttpWebResponse resp,Exception ex,OperationContext ctx)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Core.Executor.Executor.EndGetResponse[T](IAsyncResult getResponseResult)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    --- End of inner exception stack trace ---
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Core.Executor.Executor.EndExecuteAsync[T](IAsyncResult result)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Queue.CloudQueue.EndExists(IAsyncResult asyncResult)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.WindowsAzure.Storage.Core.Util.AsyncExtensions.<>c__DisplayClass1`1.<CreateCallback>b__0(IAsyncResult ar)
[04/18/2015 11:10:52 > 2d2f34: ERR ] --- End of stack trace from previous location where exception was thrown ---
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.Azure.WebJobs.Host.Queues.Listeners.QueueListener.<ExecuteAsync>d__4.MoveNext()
[04/18/2015 11:10:52 > 2d2f34: ERR ] --- End of stack trace from previous location where exception was thrown ---
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.Azure.WebJobs.Host.Timers.TaskSeriesTimer.<RunAsync>d__d.MoveNext()
[04/18/2015 11:10:52 > 2d2f34: ERR ] --- End of stack trace from previous location where exception was thrown ---
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at Microsoft.Azure.WebJobs.Host.Timers.BackgroundExceptionDispatcher.<>c__DisplayClass1.<Throw>b__0()
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,ContextCallback callback,Object state,Boolean preserveSyncCtx)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext,Object state)
[04/18/2015 11:10:52 > 2d2f34: ERR ]    at System.Threading.ThreadHelper.ThreadStart()
[04/18/2015 11:10:52 > 2d2f34: SYS INFO] Status changed to Failed
[04/18/2015 11:10:52 > 2d2f34: SYS ERR ] Job failed due to exit code -532462766

这是我的代码：

public static async Task  ManualTrigger([QueueTrigger(ConstantVars.TargetjobQueue)] TargetingJob job,TextWriter log)
{
    try
    {
        AddTextWriterToAppender(log);

        _logger.DebugFormat("Starting job");
        _logger.DebugFormat("Job details: {0}",job);

        await ProcessJob(job).ConfigureAwait(false);

        _logger.Debug("Finished job");

        RemoveTextWriterFromAppender();
    }
    catch (Exception e)
    {
        _logger.Error(string.Format("Unhandled exception was caught in ManualTrigger.n jobParams={0}",job.ToString()),e);              
    }
}