Python Docker

This is a sample flask app bundled up with Docker

Content

• Installation and Setup
• Prerequisites
• Local Development
• Build the image
• Tagging the image
• Running the image
• Working with the container
• Github Actions

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Installation and Setup

Prerequisites

Local Development

Run the following in the terminal to setup virtual environment

python3 -m venv venv
source venv/bin/activate

# install dependencies
python3 -m pip3 install -r requirements.txt

Build the Image

docker build -t python-docker .

Docker builds as latest

You can verify that by typing the following command:

docker images

# the output is similar to this
(venv) Ξ PycharmProjects/python-docker → docker images
REPOSITORY      TAG            IMAGE ID       CREATED         SIZE
python-docker   latest         23847fed8b84   4 minutes ago   121MB

Tagging the image

docker tag python-docker:latest python-docker:v1.0.0

# docker tag creates a new image, confirm by typing
docker images

# the output is similar to this
(venv) Ξ PycharmProjects/python-docker → docker images
REPOSITORY      TAG            IMAGE ID       CREATED          SIZE
python-docker   latest         23847fed8b84   16 minutes ago   121MB
python-docker   v1.0.0         23847fed8b84   16 minutes ago   121MB

Run the image

Run with -p to publish on a port and -d in detach mode. Use docker logs flask-app to check logs or with -f flag to stream the log live.

docker run -p 8000:5000 python-docker
# Flask runs on  http://127.0.0.1:8000 whiles running on port 5000 inside the 
# container

# output on the cli is similar to this
(venv) Ξ PycharmProjects/python-docker → docker run --name flask-app -p 8000:5000 python-docker
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on all addresses (0.0.0.0)
 * Running on http://127.0.0.1:5000
 * Running on http://172.17.0.2:5000
Press CTRL+C to quit
172.17.0.1 - - [21/Apr/2023 09:27:24] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [21/Apr/2023 09:27:24] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [21/Apr/2023 09:27:24] "GET /favicon.ico HTTP/1.1" 404 

Working with containers

# show running containers. or with -a to show stopped and running containers
docker ps

# show logs
docker logs flask-app

# stop a container. use container name or id
docker stop flask-app

# restart a container
docker restart flask-app

# remove a container
docker rm flask-app

NB: The docker-compose.yml file is just for reference. We are not using database in the app just yet :)

# this will build and run the container
docker compose -f docker-compose-dev.yml up --build

Github Actions

Environment variables have to be added to Github Secrets for the flow to work :) Generate DOCKERHUB_USERNAME and DOCKERHUB_TOKEN in secrets section and pick the values from Docker website account section.