Dockerfile

# Build a virtualenv using the appropriate Debian release
# * Install python3-venv for the built-in Python3 venv module (not installed by default)
# * Install gcc libpython3-dev to compile C Python modules
# * In the virtualenv: Update pip setuputils and wheel to support building new packages
FROM debian:12-slim AS build
RUN apt-get update && \
    apt-get install --no-install-suggests --no-install-recommends --yes python3-venv gcc libpython3-dev && \
    python3 -m venv /venv && \
    /venv/bin/pip install --upgrade pip setuptools wheel

# Build the virtualenv as a separate step: Only re-execute this step when requirements.txt changes
FROM build AS build-venv
COPY requirements.txt /requirements.txt
RUN /venv/bin/pip install --disable-pip-version-check -r /requirements.txt

# Copy the virtualenv and FastAPI app into a distroless image
FROM gcr.io/distroless/python3-debian12

# Copy the virtual environment from the build stage
COPY --from=build-venv /venv /venv

# Copy the FastAPI application code
COPY ./app /app
COPY start.py ./start.py

# Start the app with uvicorn using python. Uses python to get env for port as distroless doesn't have sh or bash
ENTRYPOINT ["/venv/bin/python3", "start.py"]