Python Docker

Introduction

In this tutorial, How to run Python on Docker. Python is a programming language. Python Docker image is the latest point release. 

The Docker image version was released in March 2022.

You need to install Docker on Ubuntu.

The working directory python docker:

root@devopsroles:~/dockerpython# ls -lF
total 20
-rw-r--r-- 1 root root  111 Nov 20 14:31 app.py
-rw-r--r-- 1 root root  236 Nov 20 15:00 Dockerfile
-rw-r--r-- 1 root root   20 Nov 20 14:27 requirements.txt

How to build a Docker container running a simple Python application.

Setup dockerfile python

Create a folder and create a virtual environment. This isolated the environment for the Python Docker project.

For example

mkdir dockerpython
cd dockerpython
python3 -m venv dockerpython
source dockerpython/bin/activate

Create a new file dockerfile python.

FROM python:3.9-slim-buster
ENV PYTHONUNBUFFERED=1
WORKDIR /app

COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt

COPY . .
EXPOSE 5000

CMD [ "python3", "-m" , "flask", "run", "--host=0.0.0.0", "--port=5000"]

Save and close.

Create the Python App

Create an app.py file. For example as below

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
     return 'Hello, Docker!'

Save and close.

Create the requirements.txt file. This contains dependencies for the app to run.

For example, we add the packages for the requirements.txt file.

Flask=2.0.3
pylint

Or method 2: show all packages installed via pip use pip3 freeze and save to the requirements.txt file.

pip3 install Flask
pip3 freeze | grep Flask >> requirements.txt

we will test if the works localhost using the command below

python3 -m flask run --host=0.0.0.0 --port=5000

Open the browser with the URL http://localhost:5000

Docker Build image and container

You build a Docker image from created Dockerfile. Use the command below to build the Docker image

docker build --tag dockerpython .

Tag the image using the syntax

docker tag <imageId> <hostname>/<imagename>:<tag>

For example, Tag the image.

docker tag 8fbb6cdc5e76 huupv/dockerpython:latest

Now, the Run Docker image has the created and tagged with the command line below:

docker run --publish 5000:5000 <imagename>

Use the command below to list containers running.

docker ps

The result below:

You can now test your application using http://localhost:5000 on your browser.

Docker pushed and retrieved from Docker Hub

The container will be pushed and retrieved from the Docker Hub registry. The command simple

docker push <hub-user>/<repo-name>:<tag>.

On the website Docker Hub. Click Create Repository to give the repo a name.

Create 1 repo name and description as below:

Copy the command to your terminal, replacing tagname with version latest.

In your terminal, we run the command docker login to connect the remote repository to the local environment. Add username and password to valid login.

Run the command to push to the repository you created it.

docker push <hub-user>/<repo-name>:tagname

Confirm your image to be pushed to the Docker Hub page

In any terminal, Docker pulls the Docker image from Docker Hub.

root@devopsroles:~# docker pull huupv/dockerpython:latest

For example, use Docker Compose

version: "3.9"  
services:
  web:
    build: .
    ports:
      - "5000:5000"
    volumes:
      - .:/app
      - logvol:/var/log
    links:
      - redis
  
 redis:
     image: redis
 volumes:
   logvol: {}

Conclusion

You know How to run Python on Docker. I hope this will be helpful. Thank you for reading the DevopsRoles page!