# syntax=docker/dockerfile:1.7

# ============================================================================
# Build stage: Debian 12's Python (paths/libs match the distroless runtime)
# ============================================================================
# We deliberately do NOT use python:3.11-slim-bookworm here — that image is
# Python.org's, which installs Python to /usr/local with an RPATH pointing
# back into /usr/local/lib. Distroless has libpython under /usr/lib, so the
# RPATH would break. Debian's apt-installed python3 lives at the same paths
# as distroless's, so symlinks and libpython all 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 into the venv's site-packages
RUN pip install \
      fastapi==0.115.* \
      "uvicorn[standard]==0.30.*" \
      redis==5.0.*

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

# ============================================================================
# Runtime stage: distroless Python 3.11, non-root, 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; its bin/python symlink resolves against
# distroless's /usr/bin/python3 and Debian's libpython at /usr/lib/...
COPY --from=builder --chown=nonroot:nonroot /opt/venv /opt/venv

# Application source (its own layer so source-only changes don't bust dep cache)
COPY --chown=nonroot:nonroot app.py favicon.ico /app/

USER nonroot
EXPOSE 8000

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