flask with mysql connection pool

flasklab.py

from flask import Flask, g
import os
import mysql.connector.pooling

app = Flask(__name__)

cnxpool = mysql.connector.pooling.MySQLConnectionPool(
                                                      host=os.getenv('MYSQL_HOST', '127.0.0.1'),
                                                      user=os.getenv('MYSQL_USER', 'flasklab'),
                                                      password=os.getenv('MYSQL_DATABASE', 'flasklab'),
                                                      database=os.getenv('MYSQL_PASSWORD', 'flasklab'),
                                                      pool_name="flasklab",
                                                      pool_size=10)

@app.before_request
def acquire_conn():
    if 'cxn' not in g:
        print('getting connection...')
        g.cxn = cnxpool.get_connection()

@app.teardown_request
def release_conn(exception):
    if 'cxn' in g:
        print('releasing connection...')
        g.cxn.close()

@app.route('/')
def index():
    print('start transaction to insert user...')

    g.cxn.start_transaction()
    cursor = g.cxn.cursor(prepared=True)
    cursor.execute('insert into user_info (name) values (%s)', ('my_name',))
    cursor.execute('insert into users (info_id) values (LAST_INSERT_ID())')
    g.cxn.commit()
    cursor.close()

    print('new cursor to query data...')
    cursor = g.cxn.cursor(prepared=True)
    cursor.execute('select id, info_id from users order by id desc limit %s', (1,))
    for (user_id, info_id) in cursor:
        print('user inserted: user_id={} info_id={}'.format(user_id, info_id))
    cursor.close()

    return 'Hello World!'

if __name__ == '__main__':
    app.run()