在Flask-APScheduler作业中查询模型会引发应用程序上下文运行错误

Querying model in Flask-APScheduler job raises app context RuntimeError(在Flask-APScheduler作业中查询模型会引发应用程序上下文运行错误)

问题描述

我希望使用Flask-APScheduler运行一个查询Flask-SQLAlChemy模型的作业。当作业运行时，我得到RuntimeError: application not registered on db instance and no application bound to current context。如何运行查询数据库的作业。

from flask_apscheduler import APScheduler

scheduler = APScheduler()
scheduler.init_app(app)
scheduler.start()

from models import User

def my_job():
    user = User.query.first()
    print(user)

错误发生在查询期间，然后才能打印。数据库正在应用程序的睡觉中运行，以进行其他查询。

我在设置扩展时尝试添加with app.app_context():，但没有成功。

with app.app_context()
    scheduler = APScheduler()
    scheduler.init_app(app)
    scheduler.start()

完整回溯为：

ERROR:apscheduler.executors.default:Job "run_in (trigger: interval[0:00:10], next run at: 2016-10-18 23:00:53 CEST)" raised an exception
Traceback (most recent call last):
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/apscheduler/executors/base.py", line 125, in run_job
    retval = job.func(*job.args, **job.kwargs)
  File "/Users/user/Documents/myfolder/myfolder/myfile.py", line 19, in myjob
    user = User.query.all()
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 454, in __get__
    return type.query_class(mapper, session=self.sa.session())
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/sqlalchemy/orm/scoping.py", line 71, in __call__
    return self.registry()
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/sqlalchemy/util/_collections.py", line 878, in __call__
    return self.registry.setdefault(key, self.createfunc())
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 704, in create_session
    return SignallingSession(self, **options)
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 149, in __init__
    self.app = db.get_app()
  File "/Users/user/.virtualenvs/myfolder/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 845, in get_app
    raise RuntimeError('application not registered on db '
RuntimeError: application not registered on db instance and no application bound to current context

推荐答案

我通过将应用程序添加到应用程序工厂中的SQLAlChemy实例修复了此问题：

def create_app():
    new_app = Flask(__name__)
    new_app.config.from_object('config')
    new_app.secret_key = os.urandom(12)
    db.init_app(new_app)
    db.app = new_app
    return new_app

我确实尝试过使用应用上下文，但从未成功。

这篇关于在Flask-APScheduler作业中查询模型会引发应用程序上下文运行错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！