python - 将 Celery 与 SQLAlchemy 和 Pyramid 结合使用

Question

我正在使用 Pyramid-1.2.1 创建 Web 应用程序，并将 SQLAlchemy 作为数据库后端。
现在我需要与这个应用程序一起执行一些周期性任务，我想使用 Celery 作为任务处理器，使用 SQLAlchemy 作为消息队列和结果后端。

1) 我已经安装了 Celery-2.1.4，但我不知道如何让它工作。这是我的 celeryconfig.py 文件:

# List of modules to import when celery starts.
CELERY_IMPORTS = ("my_app.tasks", )

## Result store settings.
CELERY_RESULT_BACKEND = "database"
CELERY_RESULT_DBURI = "sqlite:///MyDataBase.db"
CELERY_RESULT_SERIALIZER = "json"

## Broker settings.
BROKER_TRANSPORT = "sqlakombu.transport.Transport"
BROKER_HOST = "sqlite:///MyDataBase.db"

my_app.tasks 包含来自 celery 示例的简单添加任务。
现在当我运行时

$ celeryd -l info

我看到以下内容:

[2011-11-11 20:22:50,750: WARNING/MainProcess] celery@OrangeMac.local v2.1.4 is starting.
[2011-11-11 20:22:50,765: WARNING/MainProcess]  
Configuration ->
    . broker -> sqlakombu.transport.Transport://guest@sqlite:///MyDataBase.db/
    . queues ->
        . celery -> exchange:celery (direct) binding:celery
    . concurrency -> 4
    . loader -> celery.loaders.default.Loader
    . logfile -> [stderr]@INFO
    . events -> OFF
    . beat -> OFF
    . tasks ->
        . chatrooms.task.add
[2011-11-11 20:22:50,787: INFO/PoolWorker-1] child process calling self.run()
[2011-11-11 20:22:50,789: INFO/PoolWorker-2] child process calling self.run()
[2011-11-11 20:22:50,791: INFO/PoolWorker-3] child process calling self.run()
[2011-11-11 20:22:50,796: INFO/PoolWorker-4] child process calling self.run()
[2011-11-11 20:22:50,802: WARNING/MainProcess] celery@OrangeMac.local has started.
[2011-11-11 20:22:50,804: WARNING/MainProcess] Traceback (most recent call last):
[2011-11-11 20:22:50,805: WARNING/MainProcess] File "/Users/shashkin/python_v_env/bin/celeryd", line 8, in <module>
[2011-11-11 20:22:50,805: WARNING/MainProcess] load_entry_point('celery==2.1.4', 'console_scripts', 'celeryd')()
[2011-11-11 20:22:50,805: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/bin/celeryd.py", line 166, in main
[2011-11-11 20:22:50,805: WARNING/MainProcess] worker.execute_from_commandline()
[2011-11-11 20:22:50,806: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/bin/base.py", line 40, in execute_from_commandline
[2011-11-11 20:22:50,806: WARNING/MainProcess] return self.run(*args, **vars(options))
[2011-11-11 20:22:50,806: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/bin/celeryd.py", line 85, in run
[2011-11-11 20:22:50,806: WARNING/MainProcess] return Worker(**kwargs).run()
[2011-11-11 20:22:50,806: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/apps/worker.py", line 121, in run
[2011-11-11 20:22:50,807: WARNING/MainProcess] self.run_worker()
[2011-11-11 20:22:50,807: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/apps/worker.py", line 219, in run_worker
[2011-11-11 20:22:50,807: WARNING/MainProcess] worker.start()
[2011-11-11 20:22:50,807: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/worker/__init__.py", line 217, in start
[2011-11-11 20:22:50,808: WARNING/MainProcess] component.start()
[2011-11-11 20:22:50,808: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/worker/listener.py", line 238, in start
[2011-11-11 20:22:50,808: WARNING/MainProcess] self.reset_connection()
[2011-11-11 20:22:50,808: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/worker/listener.py", line 416, in reset_connection
[2011-11-11 20:22:50,808: WARNING/MainProcess] self.connection = self._open_connection()
[2011-11-11 20:22:50,808: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/worker/listener.py", line 480, in _open_connection
[2011-11-11 20:22:50,809: WARNING/MainProcess] max_retries=conf.BROKER_CONNECTION_MAX_RETRIES)
[2011-11-11 20:22:50,809: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/utils/__init__.py", line 276, in retry_over_time
[2011-11-11 20:22:50,809: WARNING/MainProcess] retval = fun(*args, **kwargs)
[2011-11-11 20:22:50,809: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/celery-2.1.4-py2.7.egg/celery/worker/listener.py", line 472, in _establish_connection
[2011-11-11 20:22:50,809: WARNING/MainProcess] conn.connect()                              # evaluate connection
[2011-11-11 20:22:50,809: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/carrot-0.10.7-py2.7.egg/carrot/connection.py", line 170, in connect
[2011-11-11 20:22:50,810: WARNING/MainProcess] return self.connection
[2011-11-11 20:22:50,810: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/carrot-0.10.7-py2.7.egg/carrot/connection.py", line 135, in connection
[2011-11-11 20:22:50,810: WARNING/MainProcess] self._connection = self._establish_connection()
[2011-11-11 20:22:50,810: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/carrot-0.10.7-py2.7.egg/carrot/connection.py", line 148, in _establish_connection
[2011-11-11 20:22:50,810: WARNING/MainProcess] return self.create_backend().establish_connection()
[2011-11-11 20:22:50,810: WARNING/MainProcess] File "/Users/shashkin/python_v_env/lib/python2.7/site-packages/carrot-0.10.7-py2.7.egg/carrot/connection.py", line 161, in create_backend
[2011-11-11 20:22:50,810: WARNING/MainProcess] return backend_cls(connection=self)
[2011-11-11 20:22:50,811: WARNING/MainProcess] TypeError
[2011-11-11 20:22:50,811: WARNING/MainProcess] :
[2011-11-11 20:22:50,811: WARNING/MainProcess] __init__() takes exactly 2 arguments (1 given)
[2011-11-11 20:22:50,811: INFO/MainProcess] process shutting down

我错过了什么？

2) 稍后我想在我的应用程序中启动 Celery。 celery-pylons 包安装后我应该做什么？我应该将 celery 的设置放在应用程序的 .ini 文件中吗？有人可以给我提供任何例子吗，因为我在网上找到的那些对我帮助不大。

谢谢。

Answer 1

这看起来像是 celery 包及其依赖项之间的版本兼容性问题。使用最新版本的 celery 2.4.5，您的示例就可以正常工作。使用 2.1.4 我得到同样的错误。

如果出于任何原因你只需要 2.1.4 版本的 celery，你必须找出你需要降级哪些依赖项才能使其工作。通过查看回溯，很可能是胡萝卜 dependency，但如果其他依赖项需要特定版本的 carrot，您可能会陷入依赖 hell 。

我强烈建议将 virtualenv 与 pip 一起使用，以便能够轻松地对包的版本进行试验。尝试使用 Linux 存储库中的 Python 包开发某些东西可能会非常痛苦。

buildout versions或 pip requirements解决这类问题，但据我所知， celery 没有一组固定的依赖版本。