Dockerfile

# Layer 1: Start from a base image
# python:3.11-slim is Debian Linux + Python already installed
# "slim" = minimal size, no extras we don't need
FROM python:3.11-slim

# Layer 2: Set the working directory inside the container
# All following commands run from /app
WORKDIR /app

# Layer 3: Copy ONLY requirements first (for caching - explained below)
COPY app/requirements.txt .

# Layer 4: Install Python dependencies
RUN pip install --no-cache-dir -r requirements.txt

# Layer 5: Copy the rest of your application
COPY app/ .

# Layer 6: Copy and make entrypoint executable
COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh

# Documentation: Tell users this container listens on port 5000
EXPOSE 5000

# ENTRYPOINT runs first, then CMD is passed as arguments to it
ENTRYPOINT ["/entrypoint.sh"]
CMD ["python", "app.py"]