# syntax=docker/dockerfile:1.7

# ============================================================================
# Build stage: Debian 12's Python (paths/libs match the distroless runtime)
# ============================================================================
# Don't use python:3.11-slim-bookworm — that image installs Python to /usr/local
# with an RPATH that breaks under distroless. Debian's apt python3 lives at the
# same paths as distroless's, so symlinks and libpython resolve correctly.
FROM debian:12-slim AS builder

ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1 \
    PIP_DISABLE_PIP_VERSION_CHECK=1

RUN apt-get update \
    && apt-get install -y --no-install-recommends \
         python3 python3-pip python3-venv \
    && rm -rf /var/lib/apt/lists/*

# Default (symlink) venv. /opt/venv/bin/python ends up as a symlink to
# /usr/bin/python3, which distroless also provides.
RUN python3 -m venv /opt/venv
ENV PATH=/opt/venv/bin:$PATH

# Install runtime deps (cached layer — only rebuilt when requirements.txt changes)
COPY requirements.txt /tmp/requirements.txt
RUN pip install -r /tmp/requirements.txt

# Pre-compile bytecode for faster cold start on a read-only rootfs
RUN python3 -m compileall -q /opt/venv

# Pre-create writable mount points so the runtime rootfs can stay read-only.
# `uploads/` always needs to be writable; `logs/` only if LOGGING_ENABLED=true.
RUN mkdir -p /app/uploads /app/logs

# ============================================================================
# Runtime stage: distroless Python 3.11, non-root (uid 65532), no shell
# ============================================================================
# gcr.io/distroless/python3-debian12 ships Python 3.11 with NO shell, NO
# package manager, and NO setuid binaries. The :nonroot tag pins USER to
# uid 65532 / gid 65532.
FROM gcr.io/distroless/python3-debian12:nonroot

ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1

WORKDIR /app

# Venv ships its site-packages; bin/python is a symlink resolved by distroless's
# /usr/bin/python3 and Debian's libpython under /usr/lib.
COPY --from=builder --chown=nonroot:nonroot /opt/venv /opt/venv

# Pre-created data dirs owned by the runtime user (mount writable volumes here)
COPY --from=builder --chown=nonroot:nonroot /app/uploads /app/uploads
COPY --from=builder --chown=nonroot:nonroot /app/logs /app/logs

# Application source — its own layer so app-only changes don't bust the dep cache
COPY --chown=nonroot:nonroot main.py /app/

USER nonroot
EXPOSE 8000

ENTRYPOINT ["/opt/venv/bin/python", "-m", "uvicorn"]
CMD ["main:app", "--host", "0.0.0.0", "--port", "8000"]