`flask db migrate`错误

Question

我们正在尝试运行flask db migrate和flask db upgrade，它会抛出以下错误：

Usage: flask db upgrade [OPTIONS] [REVISION]

Error: The file/path provided (C) does not appear to exist.  Please verify the path 
           is correct.  If app is not on PYTHONPATH, ensure the extension is .py

我们已将应用程序的目录添加到PYTHONPATH环境变量中，但仍然出现错误。任何帮助，将不胜感激。

下面是我们的__init__.py代码。我们错过了什么吗？

import logging
from flask import Flask
from flask_appbuilder import SQLA, AppBuilder

"""
 Logging configuration
"""

logging.basicConfig(format='%(asctime)s:%(levelname)s:%(name)s:%(message)s')
logging.getLogger().setLevel(logging.DEBUG)

app = Flask(__name__)
app.config.from_object('config')
db = SQLA(app)
appbuilder = AppBuilder(app, db.session)
migrate.init_app(app, db)


"""
from sqlalchemy.engine import Engine
from sqlalchemy import event

#Only include this for SQLLite constraints
@event.listens_for(Engine, "connect")
def set_sqlite_pragma(dbapi_connection, connection_record):
    # Will force sqllite contraint foreign keys
    cursor = dbapi_connection.cursor()
    cursor.execute("PRAGMA foreign_keys=ON")
    cursor.close()
"""    

from app import views

Answer 1

我想如果你像你一样使用迁移

migrate.init_app(app, db)  

您首先必须导入它然后声明它：

from flask_migrate import Migrate
migrate = Migrate()
migrate.init_app(app, db)

或者我认为你可以这样做：

from flask_migrate import Migrate
migrate = Migrate(app, db)