from flask import Flask, jsonify

from sqlalchemy import create_engine
from sqlalchemy.pool import QueuePool

app = Flask(__name__)

engine = create_engine(url="mysql+pymysql://root:123456@172.16.5.9:3306/demo?charset=utf8",
                       pool_size=20,
                       pool_recycle=3600 * 7,
                       poolclass=QueuePool,
                       echo=False)


def to_json(item):
    return {
        "id": item[0],
        "username": item[1],
        "email": item[2]
    }


@app.route("/", methods=["get"])
def index():
    data = {"msg": "", "data": []}
    with engine.connect() as connect:
        result = connect.execute("select id,username,email from user")
        for item in result.all():
            data["data"].append(to_json(item))
        return jsonify(data), 200


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=7002)

upstream backend {
    server 172.16.5.9:7002;
}
server {
    listen 17002;
    location / {
      proxy_pass http://backend;
    }
}

[root@izbp152ke14timzud0du15z pool]# python3 p.py
 * Serving Flask app 'p' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on all addresses.
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://172.16.5.9:7002/ (Press CTRL+C to quit)