Example Flask Docker

This is a view counter app that is written in Python using Flask framework, packaged using Docker.

✨ Quick Start in Docker

@Todo - the minimal set up to start the project. Something like:

$ git clone repo
$ docker-compose up --build

At this point, the app runs at localhost:5000

Creating a Flask App

Installing Python

Make sure to have Python installed and its package manager, pip.

python --version
pip --version

If the above command yields an error, install Python.

Debian-based distributions (Debian, Ubuntu, etc.)

sudo apt install python3 python3-pip

Red Hat-based distributions (CentOS, Fedora, etc.)

sudo yum install python3 python3-pip

Other Linux distributions

Refer to your Linux distribution's documentation for how to install Python.

Installing Flask

Create a virtual environment

python3 -m venv venv

Activate the virtual environment

source venv/bin/activate 

Install Flask

pip install flask

Then you can import Flask in your code.

import flask

Code-base structure

project-name/               # The project's root directory
└───src/                    # The project's app directory
    ├───init.sql            # Initial database
    ├───requirements.txt    # Requirements for the project
    └───main.py             # Main app

Packaging

This is packaged by using the Python container image as a base, copying the source code and installs necessary dependencies of this app and adds a startup script.

Running

There are 2 modes for running this project, "development" and "production", It's up to the developers to define how their apps would behave under development environment and production environment. For example, development mode may use SQLite as a database whereas in production, the app will use PostgreSQL.

In production, Gunicorn is used as the server and bytecodes will be generated from the source code for faster startup whereas in development, a development server from Flask is used.

Development

docker-compose up --build

Customizing

Docker images can be customized using environment variables or customized during build time using build arguments.

Environment Variables

Key	Description
MYSQL_HOST	Hostname of the database server.
MYSQL_USER	Username that will be used to log in into the database server.
MYSQL_PASSWORD	Password that will be used to log in into the database server.
MYSQL_DATABASE	Database that will be used for storing data.
BIND_ADDR	IP Address to bind into.

Build Arguments

Key	Description
PYTHON_VERSION	The version of Python that will be used for building this image, note that Python 2 is not supported.

Screenshots