Project summary

This project is a calculator with 10 digits.

It is a demonstration of a Python Flask web app put in a Docker image.

Project files explained

Flask files:

• main.py: Python file to run to start the Flask app
• templates: Directory for HTML files used by the Flask app
• templates/index.html: HTML file which contains the GUI of the calculator

Python files:

• calculator.py: The code for the calculator
• requirements.txt: List of Python packages necessary to install before the Python app can run (i.e. the Flask package)

Docker files:

• Dockerfile: Configuration file for creating the Docker image

Git files:

• .gitignore: Tells Git to ignore __pycache__ directory
• README.md: This README file which describes the project

Docker commands

These commands have been tested with Docker Desktop for Windows.

They require Docker Desktop to be running and are to be typed in a terminal window (e.g. Command Prompt or PowerShell).

Build image and container:

1. Build Docker image (terminal must be in root directory of project):

   docker build --tag calculator_image .

2. Create Docker container from image and tell it to use port 5001:

   docker create --name calculator_container -p 5001:5001 calculator_image

Start/stop container:

1. Start Docker container:

   docker start calculator_container

2. Open a browser to use the Flask app:

    "http://localhost:5001" or "http://127.0.0.1:5001"
   

3. Stop Docker container:

   docker stop calculator_container

Save/load image from tar file:

• Save Docker image to tar file (terminal must be in directory where file should be saved):

  docker save -o calculator_image.tar calculator_image

• Load Docker image from tar file (terminal must be in directory where file is located):

  docker load -i calculator_image.tar