即使 task_retry_limit=0，appengine 也会运行失败的任务两次

我发现任务队列 API 中存在错误行为。当任务失败时，appengine 总是会再次运行它，即使我告诉它不要这样做。

这是相关代码：

NO_RETRY = TaskRetryOptions(task_retry_limit=0)


class EnqueueTaskDapau(webapp2.RequestHandler):
    def get(self):
        taskqueue.add(
            url='/task_dapau',
            queue_name='DEFAULT',
            retry_options=NO_RETRY
        )


class TaskDapau(webapp2.RequestHandler):
    def get(self):
        logging.warning('Vai dar pau')
        raise BaseException('Deu pau :-)')

    def post(self):
        return self.get()


application = webapp2.WSGIApplication([
    ('/', MainPage),
    ('/enqueue_dapau', EnqueueTaskDapau),
    ('/task_dapau', TaskDapau),
], debug=True)

整个应用程序是可以在 Github 上找到 https://github.com/qmagico/gaetests所以它应该很容易重现。 当我将浏览器指向 /enqueue_dapau 时，这是我在日志中看到的内容（在 Web 控制台上）：

2014-10-30 08:31:01.054 /task_dapau 500 4ms 0kb AppEngine-Google; (+http://code.google.com/appengine) module=default version=1
W 2014-10-30 08:31:01.052 Vai dar pau
E 2014-10-30 08:31:01.053 Traceback (most recent call last): File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 267, in

2014-10-30 08:31:00.933 /task_dapau 500 3ms 0kb AppEngine-Google; (+http://code.google.com/appengine) module=default version=1
W 2014-10-30 08:31:00.931 Vai dar pau
E 2014-10-30 08:31:00.932 Traceback (most recent call last): File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 267, in

2014-10-30 08:31:00.897 /enqueue_dapau 200 91ms 0kb Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.104 Safari/537.36 module=default version=1

如果我在 Web 控制台上查看任务队列，我会看到“在最后一分钟运行 == 2” 此行为与我在本地使用 SDK 获得的行为不同：

INFO     2014-10-30 15:49:05,711 module.py:666] default: "GET /enqueue_dapau HTTP/1.1" 200 -
WARNING  2014-10-30 15:49:05,729 views.py:33] Vai dar pau
ERROR    2014-10-30 15:49:05,729 wsgi.py:279] 
Traceback (most recent call last):
  File "/home/tony/google_appengine/google/appengine/runtime/wsgi.py", line 267, in Handle
    result = handler(dict(self._environ), self._StartResponse)
  File "/home/tony/google_appengine/lib/webapp2-2.3/webapp2.py", line 1505, in __call__
    rv = self.router.dispatch(request, response)
  File "/home/tony/google_appengine/lib/webapp2-2.3/webapp2.py", line 1253, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/home/tony/google_appengine/lib/webapp2-2.3/webapp2.py", line 1077, in __call__
    return handler.dispatch()
  File "/home/tony/google_appengine/lib/webapp2-2.3/webapp2.py", line 545, in dispatch
    return method(*args, **kwargs)
  File "/home/tony/work/qmag/gaetests/src/views.py", line 37, in post
    return self.get()
  File "/home/tony/work/qmag/gaetests/src/views.py", line 34, in get
    raise BaseException('Deu pau :-)')
BaseException: Deu pau :-)
INFO     2014-10-30 15:49:05,735 module.py:666] default: "POST /task_dapau HTTP/1.1" 500 -
WARNING  2014-10-30 15:49:05,735 taskqueue_stub.py:1986] Task task4 failed to execute. The task has no remaining retries. Failing permanently after 0 retries and 0 seconds

这是一个错误吗？ （看起来真的是这样）

有一个简单的解决方法吗？

As 文档中提到 https://cloud.google.com/appengine/docs/python/taskqueue/overview-push#task_retriesApp Engine 有时会运行一个任务两次。您应该编写您的任务以确保这不会有害。