google-app-engine - TransientFailureException --> 从拉入队列中租用任务时

Question

我们在我们的场景中使用带后端的拉队列，我们​​的后端尝试在一些固定的时间间隔后从我们的拉队列中租用任务，如果没有任务，它不做任何事情，如果有任务，那些是处理 。昨天我们在我们的系统中得到了这个 TransientFailureException，这正是我的 servlet 试图从拉入队列中租用任务时发生的。异常不断出现，直到我们停止后端。

我们的代码片段——

{
    Boolean leasedTaskFromFastQueue = true;
    Queue fastQueue = QueueFactory.getQueue("FastQueue");
    Queue slowQueue = QueueFactory.getQueue("SlowQueue");

    List<TaskHandle> tasks = fastQueue.leaseTasks(
        3600, TimeUnit.SECONDS, 1);

    TaskHandle taskHandle = null;

    if(tasks.size() > 0) {

        taskHandle = tasks.get(0);

    }
}

我们在从 fastQueue 租用任务的线路上遇到错误，这是一个拉队列

<queue>
  <name>FastQueue</name>
  <mode>pull</mode>

</queue>

我也粘贴了我的错误跟踪，以防有帮助

com.google.appengine.api.taskqueue.TransientFailureException:
    at           com.google.appengine.api.taskqueue.QueueApiHelper.translateError(QueueApiHelper.java:79)
    at com.google.appengine.api.taskqueue.QueueApiHelper.translateError(QueueApiHelper.java:139)
    at com.google.appengine.api.taskqueue.QueueApiHelper.makeSyncCall(QueueApiHelper.java:53)
    at com.google.appengine.api.taskqueue.QueueImpl.leaseTasksInternal(QueueImpl.java:709)
    at com.google.appengine.api.taskqueue.QueueImpl.leaseTasks(QueueImpl.java:731)
    at com.implementhit.advancedsupport.server.queue.Backend.doGet(Backend.java:50)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.bitdual.appengine.tools.datastore.server.NamespaceFilter.doFilter(NamespaceFilter.java:96)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:102)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:249)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:135)
    at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:477)
    at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:449)
    at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:455)
    at com.google.tracing.TraceContext.runInContext(TraceContext.java:695)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:333)
    at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:325)
    at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:453)
    at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
    at java.lang.Thread.run(Thread.java:679)

Answer 1

它也发生在我们身上，TransientFailureException 是一个内部错误，据我们所知，它与我们的代码无关。如果连续发生 50 个错误，我们最终会自动重启后端。