使用 django celery 在 redis 上丢失连接时仅执行部分任务答案

【问题标题】：only part of task executed when connection lost on redis using django celery使用 django celery 在 redis 上丢失连接时仅执行部分任务
【发布时间】：2018-02-18 07:37:15
【问题描述】：

我有一个仅部分执行的 django celery 任务。

我启动了应用程序，连接看起来不错：

INFO/MainProcess] 连接到 redis://elasticache.cache.amazonaws.com:6379/0 [2018-02-17 23:27:24,314：INFO/MainProcess] 混合：搜索邻居 [2018-02-17 23:27:25,339：INFO/MainProcess] 混合：独自一人 [2018-02-17 23:27:25,604：INFO/MainProcess] worker1@test_vmstracker_com 准备好了。

我启动进程，任务被接收并执行：

[2018-02-17 23:27:49,810: INFO/MainProcess] 收到的任务： tracking.tasks.escalate[92f54d48202] 预计到达时间：[2018-02-18 07:27:59.797380+00:00] [2018-02-17 23:27:49,830: INFO/MainProcess] 收到的任务：tracking.tasks.escalate[09a0aebef72b] ETA:[2018-02-18 07:28:19.809712+00:00] [2018-02-17 23:28:00,205: WARNING/ForkPoolWorker-7] -我的应用正在运行-

然后我开始收到错误，它没有完成我的应用程序发送电子邮件的任务

[2018-02-17 23:28:00,214: 错误/ForkPoolWorker-7] 连接到 Redis 丢失：现在重试 (0/20)。 [2018-02-17 23:28:00,220: ERROR/ForkPoolWorker-7] 与 Redis 的连接丢失：重试 (1/2

有谁知道为什么只有执行然后连接丢失？

这是完整的堆栈跟踪：

[2018-02-17 23:28:19,382: WARNING/ForkPoolWorker-7] /usr/local/lib/python3.6/site-packages/celery/app/trace.py:549: RuntimeWarning: Exception raised outside body: ConnectionError("Error while reading from socket: ('Connection closed by server.',)",):
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 177, in _read_from_socket
    raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
OSError: Connection closed by server.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2879, in execute
    return execute(conn, stack, raise_on_error)
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2764, in _execute_transaction
    self.parse_response(connection, '_')
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2838, in parse_response
    self, connection, command_name, **options)
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 680, in parse_response
    response = connection.read_response()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 624, in read_response
    response = self._parser.read_response()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 284, in read_response
    response = self._buffer.readline()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 216, in readline
    self._read_from_socket()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 191, in _read_from_socket
    (e.args,))
redis.exceptions.ConnectionError: Error while reading from socket: ('Connection closed by server.',)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 177, in _read_from_socket
    raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
OSError: Connection closed by server.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/celery/app/trace.py", line 434, in trace_task
    uuid, retval, task_request, publish_result,
  File "/usr/local/lib/python3.6/site-packages/celery/backends/base.py", line 152, in mark_as_done
    self.store_result(task_id, result, state, request=request)
  File "/usr/local/lib/python3.6/site-packages/celery/backends/base.py", line 309, in store_result
    request=request, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/celery/backends/base.py", line 652, in _store_result
    self.set(self.get_key_for_task(task_id), self.encode(meta))
  File "/usr/local/lib/python3.6/site-packages/celery/backends/redis.py", line 213, in set
    return self.ensure(self._set, (key, value), **retry_policy)
  File "/usr/local/lib/python3.6/site-packages/celery/backends/redis.py", line 203, in ensure
    **retry_policy)
  File "/usr/local/lib/python3.6/site-packages/kombu/utils/functional.py", line 333, in retry_over_time
    return fun(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/celery/backends/redis.py", line 222, in _set
    pipe.execute()
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2894, in execute
    return execute(conn, stack, raise_on_error)
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2764, in _execute_transaction
    self.parse_response(connection, '_')
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2838, in parse_response
    self, connection, command_name, **options)
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 680, in parse_response
    response = connection.read_response()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 624, in read_response
    response = self._parser.read_response()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 284, in read_response
    response = self._buffer.readline()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 216, in readline
    self._read_from_socket()
  File "/usr/local/lib/python3.6/site-packages/redis/connection.py", line 191, in _read_from_socket
    (e.args,))
redis.exceptions.ConnectionError: Error while reading from socket: ('Connection closed by server.',)

  exc, exc_info.traceback)))

【问题讨论】：

好像redis关闭了连接，尝试更新到最新的redis服务器并redis python包

标签： django python-3.x redis celery django-celery

【解决方案1】：

问题是我的应用服务器和代理实例太小。我正在使用ec2。一旦我升级到大型硬件，问题就消失了。 ec2 实例或 elasticache 实例在 CPU、内存和网络方面都太小了。

【讨论】：