Question

我正在尝试使用sqlalchemy + celery beats为我的数据库中的特定类型的对象翻转一个布尔标志。但是如何从tasks.py文件中访问我的orm？

.whl

我正在使用celery beat命令运行：

celery -A task worker -l INFO --beat

但我收到以下错误：

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current_app.app_context（）行

如果我删除current_app.app_context（）行，我将收到以下错误：

raise RuntimeError('working outside of application context')
RuntimeError: working outside of application context

是否有一种特殊的方式可以进入烧瓶 - sqlalchemy orm进行芹菜任务？或者我会尝试做更好的方法吗？

到目前为止，唯一有效的解决方法是在我的应用工厂模式中添加RuntimeError: application not registered on db instance and no application bound to current context之后的以下行：

db.app = app

我正在关注此回购以创建我的芹菜应用https://github.com/mattupstate/overholt/blob/master/overholt/factory.py

Answer 1

您收到该错误是因为current_app要求应用上下文有效，但您尝试使用它来设置应用上下文。您需要使用实际应用来设置上下文，然后您可以使用current_app。

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

或者您可以使用the Flask docs中描述的模式来创建celery.Task的子类，以便默认情况下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)

如何使用芹菜任务访问orm？

1 个答案: