A simple Dockerfile

Dockerfile

# Start from an image that already contains Python 3.8.
FROM python:3.8

# Install dependencies; be explicit about versions.
RUN pip install flask==1.1

# Copy the application's source code into the image.
COPY src/ /code

# Add useful information for operators.
EXPOSE 80/tcp

# Specify how to start the application.
ENTRYPOINT python /code/main.py