Describe the bug
PyMySQL fails to connect to MySQL Docker Container. Inside the MySQL Docker Container, the logs produce an mbind: Operation not permitted. message while the backend repeatedly attempts to connect to the MySQL container but produces the error message: ERROR:__main__:(pymysql.err.OperationalError) (1045, "Access denied for user 'root'@'172.18.0.8' (using password: YES)")

To Reproduce

• Build a Python backend and MySQL docker container with docker-compose. (both build successfully) database logs after the build:

• Run a script that initializes the backend connection to the MySQL database container... the connection url scheme that is used is mysql+pymysql and the dependency pymysql is being brought in with the extra dependency: pymysql[rsa].

The connection url is completed with: mysql+pymysql://root:the correct password I promise@db/app

Where db is the name of the service in the docker-compose.yml file that builds the MySQL (I get a connection refused error if I use 0.0.0.0 127.0.0.1 or localhost:) and app is the name of the databased created, validated by the logs.

• Revisiting the logs after this it has produced an mbind: Operation not permitted message.

The db docker-compose.yml service code:

The db docker-compose.override (for some local dev additions):

Expected behavior
A connection.

Environment

• OS: MacOS up-to-date
• Server and version: Docker version 19.03.8, MySQL Docker Image (Official): https://hub.docker.com/_/mysql
• PyMySQL version: 0.10.1