我对在 celery 任务中异步执行的每个插入查询（小查询）都有问题。
在同步模式下，当我插入时，一切都完成得很好，但是当它在 apply_async() 中执行时，我得到这个：
OperationTimedOut('errors=errors=errors={}, last_host=***.***.*.***, last_host=None, last_host=None',)
追溯：
Traceback (most recent call last):
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/celery/app/trace.py", line 240, in trace_task
R = retval = fun(*args, **kwargs)
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/celery/app/trace.py", line 437, in __protected_call__
return self.run(*args, **kwargs)
File "/var/nfs_www/***/www_v1/app/mods/news_feed/tasks.py", line 26, in send_new_comment_reply_notifications
send_new_comment_reply_notifications_method(comment_id)
File "/var/nfs_www/***www_v1/app/mods/news_feed/methods.py", line 83, in send_new_comment_reply_notifications
comment_type='comment_reply'
File "/var/nfs_www/***/www_v1/app/mods/news_feed/models/storage.py", line 129, in add
CommentsFeed(**kwargs).save()
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cqlengine/models.py", line 531, in save
consistency=self.__consistency__).save()
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cqlengine/query.py", line 907, in save
self._execute(insert)
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cqlengine/query.py", line 786, in _execute
tmp = execute(q, consistency_level=self._consistency)
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cqlengine/connection.py", line 95, in execute
result = session.execute(query, params)
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cassandra/cluster.py", line 1103, in execute
result = future.result(timeout)
File "/var/nfs_www/***/env_v0/local/lib/python2.7/site-packages/cassandra/cluster.py", line 2475, in result
raise OperationTimedOut(errors=self._errors, last_host=self._current_host)
OperationTimedOut: errors={}, last_host=***.***.*.***
有人对问题有想法吗？
我找到了这个当cassandra-driver执行查询时，cassandra-driver返回错误OperationTimedOut https://stackoverflow.com/questions/24157534/when-cassandra-driver-was-executing-the-query-cassandra-driver-returned-error-o，但我的查询很少，并且仅在芹菜任务中出现问题。
UPDATE:
我做了一个测试任务，它也引发了这个错误。
@celery.task()
def test_task_with_cassandra():
from app import cassandra_session
cassandra_session.execute('use news_feed')
return 'Done'
更新2：做了这个：
@celery.task()
def test_task_with_cassandra():
from cqlengine import connection
connection.setup(app.config['CASSANDRA_SERVERS'], port=app.config['CASSANDRA_PORT'],
default_keyspace='test_keyspace')
from .models import Feed
Feed.objects.count()
return 'Done'
收到：
NoHostAvailable('Unable to connect to any servers', {'***.***.*.***': OperationTimedOut('errors=errors=Timed out creating connection, last_host=None, last_host=None',)})
从外壳我可以连接到它
UPDATE 3：
来自 github 问题上已删除的线程（在我的电子邮件中找到了这个）：（这也对我有用）
实质上，以下是我将 CQLengine 插入 Celery 的方法：
from celery import Celery
from celery.signals import worker_process_init, beat_init
from cqlengine import connection
from cqlengine.connection import (
cluster as cql_cluster, session as cql_session)
def cassandra_init():
""" Initialize a clean Cassandra connection. """
if cql_cluster is not None:
cql_cluster.shutdown()
if cql_session is not None:
cql_session.shutdown()
connection.setup()
# Initialize worker context for both standard and periodic tasks.
worker_process_init.connect(cassandra_init)
beat_init.connect(cassandra_init)
app = Celery()
这很粗糙，但是有效。我们应该在常见问题解答中添加此片段吗？
