部署Python应用程序时，您有时必须重新启动芹菜。如果有一项长期运行的任务，您可能不想杀死该任务，而是要等到任务完成。
此功能将暂停接受新任务并等待'所有任务完成。
from celery import Celery
from celery.app.control import Control
def celery_check():
app = Celery("app") # Name of the main module
control = Control(app)
control.cancel_consumer("celery") # queue name, must probably be specified once per queue, but we use a single queue
inspect = control.inspect()
while True:
active = inspect.active()
if len(active.items()) > 0:
seconds = 10
time.sleep(seconds)
else:
break