Python 芹菜为什么不节拍'；t安排定期任务？

我已经按照芹菜文档创建了一个应用程序和定期任务，如下所示：

$ tree demo/
demo/
├── config.py
├── __init__.py
└── tasks.py

$ cat demo/__init__.py 
# -*- coding: utf-8 -*-
from celery import Celery

app = Celery('demo')
app.config_from_object('demo.config')

$ cat demo/config.py 
# -*- coding: utf-8 -*-
BROKER_URL = "redis://127.0.0.1:6379"
CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

$ cat demo/tasks.py 
from demo import app
@app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
    sender.add_periodic_task(3.0, say.s(), name='say hello every 3s')

@app.task
def say():
    print("Hello!")

$ celery beat -A demo -l info --max-interval 10
celery beat v4.3.0 (rhubarb) is starting.
__    -    ... __   -        _
LocalTime -> 2019-12-12 16:26:41
Configuration ->
    . broker -> redis://127.0.0.1:6379//
    . loader -> celery.loaders.app.AppLoader
    . scheduler -> celery.beat.PersistentScheduler
    . db -> celerybeat-schedule
    . logfile -> [stderr]@%INFO
    . maxinterval -> 10.00 seconds (10.0s)
[2019-12-12 16:26:41,234: INFO/MainProcess] beat: Starting...

$ cat demo/config.py 
# -*- coding: utf-8 -*-

from datetime import timedelta

BROKER_URL = "redis://127.0.0.1:6379"

CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

CELERYBEAT_SCHEDULE = {
    'say hello every 10 seconds': {
         'task': 'demo.tasks.say',
         'schedule': timedelta(seconds=3),
    },
}
$ cat demo/tasks.py 
from demo import app

@app.task
def say():
    print("Hello!")

然后按如下方式运行芹菜节拍：

$ tree demo/
demo/
├── config.py
├── __init__.py
└── tasks.py

$ cat demo/__init__.py 
# -*- coding: utf-8 -*-
from celery import Celery

app = Celery('demo')
app.config_from_object('demo.config')

$ cat demo/config.py 
# -*- coding: utf-8 -*-
BROKER_URL = "redis://127.0.0.1:6379"
CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

$ cat demo/tasks.py 
from demo import app
@app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
    sender.add_periodic_task(3.0, say.s(), name='say hello every 3s')

@app.task
def say():
    print("Hello!")

$ celery beat -A demo -l info --max-interval 10
celery beat v4.3.0 (rhubarb) is starting.
__    -    ... __   -        _
LocalTime -> 2019-12-12 16:26:41
Configuration ->
    . broker -> redis://127.0.0.1:6379//
    . loader -> celery.loaders.app.AppLoader
    . scheduler -> celery.beat.PersistentScheduler
    . db -> celerybeat-schedule
    . logfile -> [stderr]@%INFO
    . maxinterval -> 10.00 seconds (10.0s)
[2019-12-12 16:26:41,234: INFO/MainProcess] beat: Starting...

$ cat demo/config.py 
# -*- coding: utf-8 -*-

from datetime import timedelta

BROKER_URL = "redis://127.0.0.1:6379"

CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

CELERYBEAT_SCHEDULE = {
    'say hello every 10 seconds': {
         'task': 'demo.tasks.say',
         'schedule': timedelta(seconds=3),
    },
}
$ cat demo/tasks.py 
from demo import app

@app.task
def say():
    print("Hello!")

请稍候，没有安排任何任务

但是，如果我在config中更改为set

CELERYBEAT\u SCHEDULE

，它可以很好地工作。为此，我将

demo/config.py

和

demo/tasks.py

更改如下：

$ tree demo/
demo/
├── config.py
├── __init__.py
└── tasks.py

$ cat demo/__init__.py 
# -*- coding: utf-8 -*-
from celery import Celery

app = Celery('demo')
app.config_from_object('demo.config')

$ cat demo/config.py 
# -*- coding: utf-8 -*-
BROKER_URL = "redis://127.0.0.1:6379"
CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

$ cat demo/tasks.py 
from demo import app
@app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
    sender.add_periodic_task(3.0, say.s(), name='say hello every 3s')

@app.task
def say():
    print("Hello!")

$ celery beat -A demo -l info --max-interval 10
celery beat v4.3.0 (rhubarb) is starting.
__    -    ... __   -        _
LocalTime -> 2019-12-12 16:26:41
Configuration ->
    . broker -> redis://127.0.0.1:6379//
    . loader -> celery.loaders.app.AppLoader
    . scheduler -> celery.beat.PersistentScheduler
    . db -> celerybeat-schedule
    . logfile -> [stderr]@%INFO
    . maxinterval -> 10.00 seconds (10.0s)
[2019-12-12 16:26:41,234: INFO/MainProcess] beat: Starting...

$ cat demo/config.py 
# -*- coding: utf-8 -*-

from datetime import timedelta

BROKER_URL = "redis://127.0.0.1:6379"

CELERY_TIMEZONE='UTC'
CELERY_IMPORTS = [
    "demo.tasks",
]

CELERYBEAT_SCHEDULE = {
    'say hello every 10 seconds': {
         'task': 'demo.tasks.say',
         'schedule': timedelta(seconds=3),
    },
}
$ cat demo/tasks.py 
from demo import app

@app.task
def say():
    print("Hello!")

然后使用与之前相同的命令运行芹菜节拍，周期性任务可以按预期每3秒安排一次

---

我以前的设置有什么问题？

您必须根据

--scheduler

键指定计划程序。例如，您可以尝试以下代码：

celery beat -A demo -l info --scheduler django_celery_beat.schedulers:DatabaseScheduler

---

另外，我不确定

--max interval

是否会影响您的日程安排。我认为最好删除此选项。IMHO.

芹菜4.x不使用大写配置变量-请参阅芹菜文档的一节。将列出特定于计划程序的配置参数。因此，尝试修改代码，使其具有

beat_schedule={

而不是

CELERYBEAT_schedule={

。您所说的链接也使用小写名称…

仅供参考，我想出了另一个解决方案，在配置后更改装饰程序

@app.on.\u。将
连接到
@app.on.\u finalize.connect
可以让它工作。尽管我现在不知道确切原因。
默认的调度程序是“celery.beat.PersistentScheduler”正如您在celery beat命令的输出中所看到的。大写配置变量也可以工作，因为celery 4.x也支持旧格式配置，在我的示例中，“CELERYBEAT_SCHEDULE”工作得很好。不起作用的是原始版本的代码，它在_configure.connect“+”setup_任务之后使用“@app.on_”“。我自己也遇到过这种情况。这是因为，
芹菜.py
末尾发送了\u configure
之后，
上的
，但是
任务.py
模块直到很久以后才加载（
自动发现任务（）
不会立即执行，因为Django必须完成应用程序的设置。）因此，在发送了配置后，在上用
on\u修饰的任何定期任务都不会被导入。请在此解释问题：