[英]Celery shutting down worker from task_success handler not working
我試圖讓一個工人一次只運行一個任務,然后關閉。 我已經使關機部分正常工作(這里有一些背景: celery通過在task_postrun信號中提高SystemExit來嘗試關機工作者,但總是掛起,並且主進程永遠不會退出 ),但是當它關機時,我得到了一個錯誤:
[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'
為什么會這樣呢? 它不僅不應答,而且還清除了隊列中剩下的所有其他任務(大問題)。
我該如何解決?
UPDATE
以下是更新了所有內容的堆棧跟蹤信息(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'
不建議在task_postrun中退出,因為task_postrun是在“任務主體”錯誤處理之外執行的。
任務調用sys.exit時發生的確切定義不明確,實際上取決於所使用的池。
通過多處理,子進程將簡單地被新進程代替。 在其他池中,工作程序將關閉,但這很可能會更改,從而與多處理行為保持一致。
在任務主體外部調用exit被視為內部錯誤(崩潰)。
“任務主體”是在task.__call__()
執行的任何東西。
我認為也許對此更好的解決方案是使用自定義執行策略:
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')
這不是很漂亮,但是執行策略可以優化任務的執行並且不易於擴展(工作人員通過緩存Task.Strategy來“預編譯”每種任務類型的執行路徑)
在Celery 3.1中,您可以使用“引導步驟”擴展工作人員和使用者,因此可能會有一個不錯的解決方案。
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