Dockerizing a Python App

This guide will walk you through the process of Dockerizing a Python application built with FastAPI.

Prerequisites

Before you begin, make sure you have the following prerequisites:

1. Docker installed on your machine. You can download and install Docker from the official website: https://www.docker.com/

2. Basic understanding of Python, Docker & Git

Step 1: Fork & clone the repo

First, let's fork the repository then clone it and navigate into it:

git clone https://github.com/YOUR_USER/summer-devops.git
cd summer-devops

Step 2: Dockerfile

The Dockerfile is a text file that contains a set of instructions to build a Docker image. Use the empty file named Dockerfile in the project directory and open it in a text editor.

You can try and create the Dockerfile yourself or use the following code

# Use the official Python base image
FROM python:3.9-slim

# Set the working directory inside the container
WORKDIR /app

# Copy the requirements.txt file to the container
COPY requirements.txt .

# Install the Python dependencies
RUN pip install --no-cache-dir -r requirements.txt

# Copy the rest of the application code to the container
COPY ./app .

# Expose the port on which the FastAPI app will run
EXPOSE 8000

# Start the FastAPI app
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

Step 3: Docker Compose

Docker Compose is a tool for defining and running multi-container Docker applications. It allows you to specify the services, networks, and volumes required for your application in a YAML file.

Use the existent file named docker-compose.yml in the project directory and open it in a text editor.

You can try and create the docker-compose.yaml yourself or use the following code

version: '3'
services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - 8000:8000

Step 4: Build and Run the Docker Container

Open a terminal or command prompt and navigate to the project directory (summer-devops).

To build the Docker image, run one of the following commands:

docker build -t dockerized-python-app .

or

docker-compose build

Once the build process is complete, you can run the Docker container with one of the following commands:

docker run --it --rm -p 8000:8000 dockerized-python-app

or

docker-compose up

Step 5: Test the App

Open your web browser and visit http://localhost:8000/ to see the "OK" message. You can also try accessing http://localhost:8000/af to see the "Freak" message.

Congratulations! You have successfully Dockerized your Python.

Additional Notes

• You can stop the running Docker container by pressing Ctrl+C in the terminal or command prompt where the container is running.

• If you make changes to your application code or Dockerfile, you will need to rebuild the Docker image using the docker-compose build command before running it again.

• Remember to shut down the Docker container when you're done by running docker-compose down or by pressing Ctrl+C in the project directory.

That's it! You now have a Dockerized Python app. Happy coding!