__init__.py

import os
from urllib.parse import quote

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

DB_ROOT_USER = os.getenv("DB_ROOT_USER", "root")
DB_ROOT_PASSWD = os.getenv("DB_ROOT_PASSWD")
DB_USER = os.getenv("DB_USER")
DB_PASSWD = os.getenv("DB_PASSWD")
db_user = ""
db_passwd = ""
if DB_USER:
    db_user = DB_USER
    db_passwd = DB_PASSWD
else:
    db_user = "root"
    db_passwd = DB_ROOT_PASSWD

DB_HOST = os.getenv("DB_HOST", "seatable-mysql")
DB_PORT = os.getenv("DB_PORT", "3306")
DATABASE_NAME = os.getenv("DATABASE_NAME", "scheduler")

# DBSession for flask and scheduler
db_url = "mysql+pymysql://%s:%s@%s:%s/%s?charset=utf8mb4" % (
    quote(db_user),
    quote(db_passwd),
    quote(DB_HOST),
    quote(DB_PORT),
    quote(DATABASE_NAME),
)
db_kwargs = dict(pool_recycle=300, echo=False, echo_pool=False)

engine = create_engine(db_url, **db_kwargs)
Base = declarative_base()
DBSession = sessionmaker(bind=engine)