minimal_docker_flask_mysql

A minimal viable example of using docker-compose to setup flask and mysql for a webapp

Purpose of this repository

Suppose you want to create a simple web application using python and a local database. You could set up your own web server on a dedicated Linux machine, but the system administration can be a burden. You could use a virtual machine to reduce some of that burden and cost, but installing and configuring services is still quite a bit of work. Instead, a docker virtual file system can setup the services for you, and it is resource-efficient.

Here is an example of how to configure and run docker, flask, and MySQL. There are some similar examples on github, but this example is newer (2024), uses up-to-date versions of mysql and flask, and demonstrates more current methods for passing passwords, isolating networks, and initializing mysql.

To run

• Install docker.
• Checkout this code, and open a shell in the checkout directory.
• mkdir database_data
• docker compose up --build

Explanation of processes

A docker container is created for the database service, and another for the webserver. When creating the initial database container, the docker environment variables like MYSQL_ROOT_PASSWORD_FILE cause the base mysql image to automatically create a database, set the admin password, and set the webserver's database user and password. The database network and port are exposed only to the webserver, and the webserver exposes itself to the world. The webserver container automatically starts the flask service, which initially creates a database table, and then updates the database with each webpage served.

Explanation of directories and files

File	Description
databaseData/	A directory on the host machine that persists database data between docker container instantiations
secrets/	Files containing database passwords
webserver/	Code for the flask webserver
Dockerfile	Docker sub-configuration for the webserver
main.py	Main python entry point
static	Files served as-is
templates	Files served with variable substitutions and other template logic
docker-compose.yml	The main docker configuration file

To do next

• Modify the passwords in your secrets/ files.

• Modify the python code in webserver/main.py to create your database schema, website content, and business logic.

• If you want the database to be reconfigured from scratch, recreate the database data directory.

  rm -rf database_data && mkdir database_data