Django Celery 定期任务运行但 RabbitMQ 队列未被消耗

Question

问题

通过 celery 的周期性任务调度器运行任务后，beat，为什么我在 RabbitMQ 中还有这么多未使用的队列？

设置

• 在 Heroku 上运行的 Django Web 应用程序
• 通过 celery beat 安排的任务
• 任务通过 celery worker 运行
• 消息代理是来自 CouldAMQP 的 RabbitMQ

Procfile

web: gunicorn --workers=2 --worker-class=gevent --bind=0.0.0.0:$PORT project_name.wsgi:application
scheduler: python manage.py celery worker --loglevel=ERROR -B -E --maxtasksperchild=1000
worker: python manage.py celery worker -E --maxtasksperchild=1000 --loglevel=ERROR

settings.py

CELERYBEAT_SCHEDULE = {
    'do_some_task': {
        'task': 'project_name.apps.appname.tasks.some_task',
        'schedule': datetime.timedelta(seconds=60 * 15),
        'args': ''
    },
}

tasks.py

@celery.task
def some_task()
    # Get some data from external resources
    # Save that data to the database
    # No return value specified

结果

每次任务运行时，我都会（通过 RabbitMQ Web 界面）：

• 我的“已排队消息”下处于“就绪”状态的附加消息
• 一个附加队列，其中有一条消息处于“就绪”状态
  • 此队列没有列出的消费者

Answer 1

它最终成为我对CELERY_RESULT_BACKEND 的设置。

以前是：

CELERY_RESULT_BACKEND = 'amqp'

将 RabbitMQ 更改为后，我不再有未使用的消息/队列：

CELERY_RESULT_BACKEND = 'database'

发生的事情似乎是，在执行任务后，celery 正在通过rabbitmq 发送有关该任务的信息，但是，没有任何设置来使用这些响应消息，因此一堆未读的消息结束了在队列中。

注意：这意味着 celery 将添加记录任务结果的数据库条目。为了防止我的数据库被无用的消息加载，我补充说：

# Delete result records ("tombstones") from database after 4 hours
# http://docs.celeryproject.org/en/latest/configuration.html#celery-task-result-expires
CELERY_TASK_RESULT_EXPIRES = 14400

---

Settings.py 中的相关部分

########## CELERY CONFIGURATION
import djcelery
# https://github.com/celery/django-celery/
djcelery.setup_loader()

INSTALLED_APPS = INSTALLED_APPS + (
    'djcelery',
)

# Compress all the messages using gzip
# http://celery.readthedocs.org/en/latest/userguide/calling.html#compression
CELERY_MESSAGE_COMPRESSION = 'gzip'

# See: http://docs.celeryproject.org/en/latest/configuration.html#broker-transport
BROKER_TRANSPORT = 'amqplib'

# Set this number to the amount of allowed concurrent connections on your AMQP
# provider, divided by the amount of active workers you have.
#
# For example, if you have the 'Little Lemur' CloudAMQP plan (their free tier),
# they allow 3 concurrent connections. So if you run a single worker, you'd
# want this number to be 3. If you had 3 workers running, you'd lower this
# number to 1, since 3 workers each maintaining one open connection = 3
# connections total.
#
# See: http://docs.celeryproject.org/en/latest/configuration.html#broker-pool-limit
BROKER_POOL_LIMIT = 3

# See: http://docs.celeryproject.org/en/latest/configuration.html#broker-connection-max-retries
BROKER_CONNECTION_MAX_RETRIES = 0

# See: http://docs.celeryproject.org/en/latest/configuration.html#broker-url
BROKER_URL = os.environ.get('CLOUDAMQP_URL')

# Previously, had this set to 'amqp', this resulted in many read / unconsumed
# queues and messages in RabbitMQ
# See: http://docs.celeryproject.org/en/latest/configuration.html#celery-result-backend
CELERY_RESULT_BACKEND = 'database'

# Delete result records ("tombstones") from database after 4 hours
# http://docs.celeryproject.org/en/latest/configuration.html#celery-task-result-expires
CELERY_TASK_RESULT_EXPIRES = 14400
########## END CELERY CONFIGURATION

Answer 2

看起来您正在从已使用的任务中获得响应。

您可以通过以下方式避免这种情况：

@celery.task(ignore_result=True)