sqlalchemy通过ssh隧道连接mysql

from sshtunnel import SSHTunnelForwarder
from sqlalchemy import Column, String, Integer,  DateTime, create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base


mysql_host = mysql_host
mysql_port = mysql_port
mysql_user = mysql_user
mysql_password = mysql_passwd
mysql_db = mysql_db
ssh_host = ssh_host
ssh_port = ssh_port 
ssh_user = ssh_user
ssh_password = ssh_passwd

Base = declarative_base()
class Behavior(Base):
    __tablename__ = 'user'
    id = Column(Integer, primary_key=True)
    name= Column(String(100))
    gender= Column(String(256))

 with SSHTunnelForwarder(
            (ssh_host, ssh_port),  # Remote server IP and SSH port
            ssh_username=ssh_user,
            ssh_password=ssh_passwd,
            remote_bind_address=(mysql_host, mysql_port)
    ) as server:
        server.start()  # start ssh sever
        local_port = str(server.local_bind_port)
        engine = create_engine('mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8'.format(mysql_user,
                                                                                    mysql_passwd,
                                                                                    '127.0.0.1',
                                                                                    local_port,
                                                                                    mysql_db),
                               pool_recycle=1)

        Session = sessionmaker(bind=engine)
        session = Session()
        session.query(User).filter(User.id== 1).all()