Dockerfile

# ---------- stage 1: build ----------
FROM python:3.9-slim AS builder
WORKDIR /src
COPY . .
RUN pip install --prefix=/install --no-cache-dir -r requirements.txt
# optional: compile to .pyc or a zipapp
RUN python -m compileall -b app.py

# ---------- stage 2: runtime ----------
FROM python:3.9-slim
WORKDIR /app
# bring in only what you need
COPY --from=builder /install /usr/local
COPY --from=builder /src/app.pyc ./app.pyc          
ENTRYPOINT ["python", "app.pyc"]