Flask 如何使用芹菜任务访问orm？

我正在尝试使用sqlalchemy+Cellery beats为数据库中特定类型的对象翻转布尔标志。但是如何从tasks.py文件访问orm

from models import Book
from celery.decorators import periodic_task
from application import create_celery_app

celery = create_celery_app()
# Create celery: http://flask.pocoo.org/docs/0.10/patterns/celery/

# This task works fine
@celery.task
def celery_send_email(to,subject,template):
    with current_app.app_context():
        msg = Message(
            subject,
            recipients=[to],
            html=template,
            sender=current_app.config['MAIL_DEFAULT_SENDER']
        )
        return mail.send(msg)

#This fails
@periodic_task(name='release_flag',run_every=timedelta(seconds=10))
def release_flag():
    with current_app.app_context(): <<< #Fails on this line
        books = Book.query.all() <<<< #Fails here too
        for book in books:
          book.read = True
          book.save()

返回到当前的app.app\u context（）行

如果删除当前的\u app.app\u context（）行，将出现以下错误：

RuntimeError: application not registered on db instance and no application bound to current context

对于芹菜任务，是否有特定的方式访问Alchemy orm？还是有更好的方法来实现我的目标

到目前为止，唯一有效的解决方法是在my application factory模式中的

db.init_app（app）

之后添加以下行：

db.app=app

---

我按照此回购创建了我的芹菜应用程序

您会遇到此错误，因为当前的应用程序需要应用程序上下文才能工作，但您正在尝试使用它设置应用程序上下文。您需要使用实际的应用程序来设置上下文，然后您可以使用

current\u app

with app.app_context():
    # do stuff that requires the app context

或者，您可以使用类似于to subclass

Cellery.Task

中所述的模式，以便默认情况下它了解应用程序上下文

from celery import Celery

def make_celery(app):
     celery = Celery(app.import_name, broker=app.config['CELERY_BROKER_URL'])
     celery.conf.update(app.config)
     TaskBase = celery.Task

     class ContextTask(TaskBase):
         abstract = True

         def __call__(self, *args, **kwargs):
             with app.app_context():
                 return TaskBase.__call__(self, *args, **kwargs)

     celery.Task = ContextTask
     return celery

 celery = make_celery(app)

from celery import Celery

def make_celery(app):
     celery = Celery(app.import_name, broker=app.config['CELERY_BROKER_URL'])
     celery.conf.update(app.config)
     TaskBase = celery.Task

     class ContextTask(TaskBase):
         abstract = True

         def __call__(self, *args, **kwargs):
             with app.app_context():
                 return TaskBase.__call__(self, *args, **kwargs)

     celery.Task = ContextTask
     return celery

 celery = make_celery(app)