Setting up SQLAlchemy with Application Factory pattern and Blueprints

admin.py

from flask import current_app, Blueprint, render_template
from database import db_session
from model import Product

admin = Blueprint('admin', __name__, url_prefix='/admin')
  
@admin.route('/')
def index():
  product = db_session.query(Product).first()

  return product.name

app.py

from flask import Flask
from database import init_engine, init_db


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

  init_engine(app.config['SQLALCHEMY_DATABASE_URI'])
  init_db()

  from admin import admin
  app.register_blueprint(admin)

  return app

if __name__ == '__main__':
  app = init_app()
  app.run('127.0.0.1', 5000, debug=True)

database.py

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker, create_session
from sqlalchemy.ext.declarative import declarative_base

engine = None
db_session = scoped_session(lambda: create_session(bind=engine))
  
Base = declarative_base()
#Base.query = db_session.query_property()

def init_engine(uri, **kwargs):
  global engine
  engine = create_engine(uri, **kwargs)
  return engine

def init_db():
  from model import Product
  Base.metadata.create_all(bind=engine)

model.py

from sqlalchemy import Column, Integer, String
from database import Base

class Product(Base):
  __tablename__ = 'products'
  
  id = Column(Integer, primary_key=True)
  name = Column(String(50), unique=True)