Failed to connect python and MySQL using Docker Compose - mysql

Question

I am trying to connect to MySQL database using Docker Compose and I get the following error
Traceback (most recent call last):
| File "/usr/local/lib/python3.9/site-packages/mysql/connector/connection_cext.py", line 268, in _open_connection
| self._cmysql.connect(**cnx_kwargs)
| _mysql_connector.MySQLInterfaceError: Can't connect to MySQL server on '172.22.0.2:3306' (110)
|
| The above exception was the direct cause of the following exception:
| Traceback (most recent call last):
| File "//script.py", line 19, in <module>
| cnx = mysql.connector.connect(host='172.22.0.2', user='user', password='pass', database='db', port=3306)
| File "/usr/local/lib/python3.9/site-packages/mysql/connector/pooling.py", line 286, in connect
| return CMySQLConnection(*args, **kwargs)
| File "/usr/local/lib/python3.9/site-packages/mysql/connector/connection_cext.py", line 101, in __init__
| self.connect(**kwargs)
| File "/usr/local/lib/python3.9/site-packages/mysql/connector/abstracts.py", line 1108, in connect
| self._open_connection()
| File "/usr/local/lib/python3.9/site-packages/mysql/connector/connection_cext.py", line 273, in _open_connection..
| raise get_mysql_exception(mysql.connector.errors.DatabaseError: 2003 (HY000): Can't connect to MySQL server on '172.22.0.2:3306'
In my programm I have to containers: for python script and for MySQL database. Both containers are built successfully and db container starts just fine.
172.22.0.2 stands for ip address in network I've created (see docker-compose).
My python script simply connects to the database using mysql-connector.
The code is the following
Dockerfile for script
FROM python:3.9
COPY script.py script.py
RUN pip install mysql-connector-python
script.py
import mysql.connector
cnx = mysql.connector.connect(host='172.22.0.2', user='user', password='pass', database='db', port=3306)
docker-compose.yaml
version: "3"
services:
db:
image: mysql
container_name: db
command: '--init-file /data/app/init.sql'
ports:
- "3306:3306"
volumes:
- "./init.sql:/data/app/init.sql"
environment:
MYSQL_DATABASE: "db"
MYSQL_USER: "user"
MYSQL_PASSWORD: "pass"
MYSQL_ROOT_PASSWORD: "pass"
networks:
net:
ipv4_address: 172.22.0.2
script:
build:
context: ./
dockerfile: Dockerfile
depends_on:
- db
links:
- db
container_name: script
command: sh -c "sleep 10s ; python script.py"
networks:
net:
ipv4_address: 172.22.0.3
networks:
net:
driver: bridge
ipam:
driver: default
config:
- subnet: 172.22.0.0/24
gateway: 172.22.0.1
init.sql
CREATE DATABASE IF NOT EXIST db;
USE db;