我正在尝试让一个worker一次只运行一个任务,然后关闭。我已经让关机部分正常工作(这里有一些背景:celery trying shutdown worker by raising SystemExit in task_postrun signal but always hangs and the main process never exits),但当它关闭时,我收到一个错误:
[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'
为什么会这样?它不仅不是ack,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?
的更新
下面是更新所有内容的堆栈跟踪(pip install -U kombu amqp amqplib celery):
[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'
答案 0 :(得分:0)
不推荐退出task_postrun,因为task_postrun是在“任务主体”错误处理之外执行的。
当一个任务调用sys.exit时没有明确定义,究竟会发生什么 实际上它取决于所使用的池。
通过多处理,子进程将简单地替换为新进程。 在其他池中,工作人员将关闭,但这可能会发生变化 这样它与多处理行为一致。
在任务正文之外调用exit被视为内部错误(崩溃)。
“任务主体”是在task.__call__()
我认为可能更好的解决方案是使用自定义执行 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')
这并不完美,但执行策略是优化的 任务执行并且不易扩展(工作人员“预编译”执行 每个任务类型的路径,通过缓存Task.Strategy)
在Celery 3.1中,你可以使用“bootsteps”扩展工人和消费者,很可能 那时会有一个漂亮的解决方案。