Python mysql-connector-python: how to connect to docker container from terminal for python application with mysql-connector-python

For my university data base project we must create a python application with mysql-connector-python and docker.

We had made a docker-compose for MySQL that was working well with application. Due to a lack of comprehension the python app moved from a container to the local terminal. From that point the python app did no more connect to SQL container.

docker-compose.yml

version: "3.9"
services:
  mysql:
    restart: always
    container_name: "mysql"
    image: mysql:latest
    ports:
      - 3306:3306
    expose:
      - 3306
    environment:
      - MYSQL_ROOT_PASSWORD=password
      - MYSQL_DATABASE=mysql
      - MYSQL_USER=user
      - MYSQL_PASSWORD=password

python main.py script:

# pip install -r requirements.txt
# # in requerements.txt
# # line1: mysql-connector-python
# # line2: 
import mysql.connector as mysql

def main():
    cnx = mysql.connect(
        user='user', 
        password='password', 
        database='mysql',
        host='127.0.0.1', 
        port=3306
    )
    cursor = cnx.cursor()

    cursor.execute("CREATE TABLE IF NOT EXISTS test(id INTEGER(64) PRIMARY KEY, name VARCHAR(255))")

    cursor.execute("INSERT INTO test VALUES (2, 'bla')")
    cursor.execute("INSERT INTO test VALUES (3, 'blabla')")
    cursor.execute("INSERT INTO test VALUES (4, 'blablabla')")

    cursor.execute("SELECT * FROM test")
    for row in cursor.fetchall():
        print(row)
    
    cursor.close()
    cnx.close()

if __name__ == "__main__":
    main()

First I start the docker container with the following command:

$ docker-compose down
$ docker-compose build
$ docker-compose up

I wait until the container start and start the python app with:

$ python main.py

In another terminal.

The error that append is the following one: _mysql_connector.MySQLInterfaceError: Unknown MySQL server host 'mysql' (11001)

The exception is handling but never end to process.

Personnal issue:

Python: 3.11.1

Windows: 11

Docker: 20.10.17

In order to fix that host server error, I search in followed documentation:

• https://peps.python.org/pep-0249/#connection
• https://dev.mysql.com/doc/connector-python/en/connector-python-connectargs.html

And check the tag mysql-connector-python on Stack Overflow.

Does someone can help me to find what did I miss ?

I deleted the 'expose' attribute in docker compose to fix it

After update:

version: "3.9"
services:
  mysql:
    restart: always
    container_name: "mysql"
    image: mysql:latest
    ports:
      - 3306:3306
    environment:
      - MYSQL_ROOT_PASSWORD=password
      - MYSQL_DATABASE=mysql
      - MYSQL_USER=user
      - MYSQL_PASSWORD=password