Docker and Python

For this assignment you will be combining Docker with Python to create a program that generates a QR code PNG file that contains a URL. The QR code can be viewed with the camera on your phone to allow a user to click on it and send them to the target website. You must make your program generate a QR code that takes someone to your GitHub homepage i.e. https://github.com/kaw393939

Setup

1. Goto Docker.com and Install docker - https://www.docker.com/get-started/
2. Signup for your own Docker account

Submission Requirements:

1. Add the QR code image that links to your own GitHub homepage that you generate to the readme.md file, so that it appears below

2. Add an image of viewing the log of successfully creating the QR code below.

Lesson Video

1. Scaling and Backend Software Engineering
2. Docker and Cloud Computing Intro

Readings / Tutorials - No, really you should read these

• Containerization vs. Virtualization
• Official docker Getting Started - Go over all the sections
• Entrypoint vs. CMD vs. RUN
• Make QR with Python
• Make Dockerfile
• Args and Environment Variables in Docker

Building the Image

docker build -t my-qr-app .

This command builds a Docker image named my-qr-app from the Dockerfile in the current directory (.).

Running the Container with Default Settings

docker run -d --name qr-generator my-qr-app

Runs your QR code generator application in detached mode (-d) with a container named qr-generator.

Setting Environment Variables for QR Code Customization

docker run -d --name qr-generator \
  -e QR_DATA_URL='https://example.com' \
  -e QR_CODE_DIR='qr_codes' \
  -e QR_CODE_FILENAME='exampleQR.png' \
  -e FILL_COLOR='blue' \
  -e BACK_COLOR='yellow' \
  my-qr-app

Customizes the QR code generation settings through environment variables.

Sharing a Volume for QR Code Output

docker run -d --name qr-generator \
  -v /host/path/for/qr_codes:/app/qr_codes \
  my-qr-app

Mounts a host directory to the container for storing QR codes.

Combining Volume Sharing and Environment Variables

docker run -d --name qr-generator \
  -e QR_CODE_DIR='qr_codes' \
  -e FILL_COLOR='blue' \
  -e BACK_COLOR='yellow' \
  -v /host/path/for/qr_codes:/app/qr_codes \
  my-qr-app

A comprehensive command that configures the QR code settings and mounts volumes for QR codes.

Setting the arg for the url from the terminal

docker run -v .:/app qrcode --url htt/www.nobdoy.com

This is how you would set the url for the qr code

Changing the arg for the url from the terminal

1. Clear Docker Cache and Rebuild Image First, ensure that you're working with the most up-to-date image. You can clear the cache and rebuild the image by running the following commands:

   docker system prune -a  # This will remove all unused images, containers, and cache
   docker build -t qrprog .  # Rebuild the image from scratch

2. Then, run the container again, passing the --url argument explicitly:

   
   docker run -v $(pwd):/app qrprog --url "https://new-url-you-want.com"

### Basic Docker Commands Explained

**Building an Image**

```sh
docker build -t image_name .

Builds a Docker image with the tag image_name from the Dockerfile in the current directory.

Running a Container

docker run --name container_name image_name

Runs a container named container_name from image_name in the foreground / attached mode

docker run -d --name container_name image_name

Runs a container named container_name from image_name in detached mode

Listing Running Containers

docker ps

Shows a list of all running containers.

Stopping a Container

docker stop container_name

Removing a Container

docker rm container_name

Listing Docker Images

docker images

Lists all Docker images available on your machine.

Removing a Docker Image

docker rmi image_name

Removes a Docker image.

Viewing Logs of a Container

docker logs container_name

Displays the logs from a running or stopped container.

These commands cover the essentials of building, running, and managing Docker containers and images, along with specific examples for your QR code generation application.