芹菜关闭从task_success处理程序不工作的工人

Question

我试图让一个工人一次只运行一个任务，然后关机。我已经得到了切断部正常工作（一些背景这里：celery trying shutdown worker by raising SystemExit in task_postrun signal but always hangs and the main process never exits），但是当它关​​闭时，我发现了一个错误：

[2013-02-13 12:19:05,689: CRITICAL/MainProcess] Couldn't ack 1, reason:AttributeError("'NoneType' object has no attribute 'method_writer'",) 
Traceback (most recent call last): 
    File "/usr/local/lib/python2.7/site-packages/kombu/transport/base.py", line 104, in ack_log_error 
    self.ack() 
    File "/usr/local/lib/python2.7/site-packages/kombu/transport/base.py", line 99, in ack 
    self.channel.basic_ack(self.delivery_tag) 
    File "/usr/local/lib/python2.7/site-packages/amqplib/client_0_8/channel.py", line 1742, in basic_ack 
    self._send_method((60, 80), args) 
    File "/usr/local/lib/python2.7/site-packages/amqplib/client_0_8/abstract_channel.py", line 75, in _send_method 
    self.connection.method_writer.write_method(self.channel_id, 
AttributeError: 'NoneType' object has no attribute 'method_writer' 

这究竟是为什么？它不仅没有缺陷，而且还清除了队列中剩下的所有其他任务（大问题）。

我该如何解决这个问题？

UPDATE

下面是一切更新堆栈跟踪（PIP安装-U海带AMQP amqplib芹菜）：

[2013-02-13 11:58:05,357: CRITICAL/MainProcess] Internal error: AttributeError("'NoneType' object has no attribute 'method_writer'",) 
Traceback (most recent call last): 
    File "/usr/local/lib/python2.7/dist-packages/celery/worker/__init__.py", line 372, in process_task 
    req.execute_using_pool(self.pool) 
    File "/usr/local/lib/python2.7/dist-packages/celery/worker/job.py", line 219, in execute_using_pool 
    timeout=task.time_limit) 
    File "/usr/local/lib/python2.7/dist-packages/celery/concurrency/base.py", line 137, in apply_async 
    **options) 
    File "/usr/local/lib/python2.7/dist-packages/celery/concurrency/base.py", line 27, in apply_target 
    callback(target(*args, **kwargs)) 
    File "/usr/local/lib/python2.7/dist-packages/celery/worker/job.py", line 333, in on_success 
    self.acknowledge() 
    File "/usr/local/lib/python2.7/dist-packages/celery/worker/job.py", line 439, in acknowledge 
    self.on_ack(logger, self.connection_errors) 
    File "/usr/local/lib/python2.7/dist-packages/kombu/transport/base.py", line 98, in ack_log_error 
    self.ack() 
    File "/usr/local/lib/python2.7/dist-packages/kombu/transport/base.py", line 93, in ack 
    self.channel.basic_ack(self.delivery_tag) 
    File "/usr/local/lib/python2.7/dist-packages/amqp/channel.py", line 1562, in basic_ack 
    self._send_method((60, 80), args) 
    File "/usr/local/lib/python2.7/dist-packages/amqp/abstract_channel.py", line 57, in _send_method 
    self.connection.method_writer.write_method(
AttributeError: 'NoneType' object has no attribute 'method_writer' 

Answer 1

在task_postrun退出不推荐，因为task_postrun是在“任务体”错误处理之外执行的。

当一个任务调用sys.exit没有明确定义时，会发生什么， 实际上它取决于正在使用的池。

随着多处理，子进程将被一个新进程所取代。 在其他池中，工作人员将关闭，但这可能会改变 ，以便它与多处理行为一致。

调用任务体外的退出被视为内部错误（崩溃）。

“任务体”无论是在task.__call__()

执行我想，也许这更好的解决办法是使用自定义的执行 策略：

from celery.worker import strategy 
from functools import wraps 

@staticmethod 
def shutdown_after_strategy(task, app, consumer): 

    default_handler = strategy.default(task, app, consumer) 

    def _shutdown_to_exit_after(fun): 
     @wraps(fun) 
     def _inner(*args, **kwargs): 
      try: 
       return fun(*args, **kwargs) 
      finally: 
       raise SystemExit() 
     return _inner 
    return _decorate_to_exit_after(default_handler) 

@celery.task(Strategy=shutdown_after_strategy) 
def shutdown_after(): 
    print('will shutdown after this') 

这是不完全的美丽，但执行策略是优化 任务执行并且不容易扩展（工作人员通过缓存Task.Strategy“预编译”每个任务类型的执行 路径）

在Celery 3.1中，您可以使用“bootsteps”扩展工作人员和消费者，因此很可能会有一个漂亮的解决方案。