如何将 Flask-sqlalchemy 与 Google Cloud Functions 结合使用？

Question

如何flask-sqlalchemy与 Google Cloud Functions 和 Cloud SQL 等功能集成？

看一下最小的应用程序示例，它包装了app变量：

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)

    def __repr__(self):
        return '<User %r>' % self.username

但我的 Google Cloud Function 无法访问任何名为的内容app：

def my_function(request):
    return "Hello world!"

创建我自己的应用程序app = Flask(__name__)不起作用，因为 Cloud Functions 不使用此应用程序来返回响应。

Answer 1

你可以用flask.current_app它代替。您还必须配置flask-sqlalchemy为使用 CloudSQL 提供的 Unix Domain Socket：

from flask import current_app as app
from flask_sqlalchemy import SQLAlchemy

# Set these in the environment variables for the function
db_user = os.environ.get('CLOUD_SQL_USERNAME')
db_password = os.environ.get('CLOUD_SQL_PASSWORD')
db_name = os.environ.get('CLOUD_SQL_DATABASE_NAME')
db_connection_name = os.environ.get('CLOUD_SQL_CONNECTION_NAME')

# This is for Postgres, it's similar for MySQL
app.config['SQLALCHEMY_DATABASE_URI'] = f'postgresql://{db_user}:{db_password}@/{db_name}?host=/cloudsql/{db_connection_name}'

# This must be set, determine which is best for you
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)
...

User然后您可以在函数中查询模型：

def my_function(request):
    user = User.query.first()
    return f"Hello {user.username)!"