使用应用程序工厂进行Flask迁移时出错

时间:2018-02-03 23:38:00

标签: python flask factory-pattern flask-migrate flask-cli

run.py

db = SQLAlchemy()
migrate = Migrate()

def create_app():
    app = Flask(__name__)
    db.app = app
    db.init_app(app)
    migrate.init_app(app, db)
    return app

if __name__ == '__main__':
    application = create_app()
    application.run()

manage.py

from flask_migrate import MigrateCommand, Manager

from run import create_app


manager = Manager(create_app())
manager.add_command('db', MigrateCommand)

当我运行时:python manage.py db init

Traceback (most recent call last):
  File "manage.py", line 6, in <module>
    manager = Manager(create_app())
TypeError: 'NoneType' object is not callable

当我跑:flask db init

Usage: flask db init [OPTIONS]

Error: Could not locate Flask application. You did not provide the FLASK_APP environment variable.

For more information see http://flask.pocoo.org/docs/latest/quickstart/

我尝试将FLASK_APP导出为run,run.py,run.create_app,run:create_app(),但我仍然收到上面显示的错误。导致此错误的原因是什么?

2 个答案:

答案 0 :(得分:2)

flask_migrate会尝试使用flask-script中的管理员,但仅在安装了flask-script时才会使用。

简单地做,它应该工作。您也可以直接从flask_script导入。

pip install flask_script

<强> manage.py

from flask_migrate import MigrateCommand
from flask_script import Manager
from run import create_app

app = create_app()
manager = Manager(app)
manager.add_command('db', MigrateCommand)

答案 1 :(得分:2)

运行Flask-Migrate命令有两种方法。较新的方法使用Flask CLI,较旧的方法使用Flask-Script。由于您似乎没有安装Flask-Script,我将假设您打算使用Flask CLI。

所以你需要扔掉manage.py因为那只适用于Flask-Script。然后将application变量移动到全局范围:

db = SQLAlchemy()
migrate = Migrate()

def create_app():
    app = Flask(__name__)
    db.app = app
    db.init_app(app)
    migrate.init_app(app, db)
    return app

application = create_app()

if __name__ == '__main__':
    application.run()

然后设置FLASK_APP变量:

$ export FLASK_APP=run.py

现在您应该可以使用flask run运行应用程序,使用flask db <command>运行数据库命令。