Dockerfile

# ---- Build stage: resolve and install dependencies with uv ----
FROM python:3.12-slim AS builder

# Compile .pyc at install time: faster cold start, lower peak RSS on boot
ENV PYTHONUNBUFFERED=1
ENV UV_COMPILE_BYTECODE=1
ENV UV_LINK_MODE=copy

WORKDIR /app

COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv

COPY pyproject.toml uv.lock ./
RUN uv sync --frozen --no-dev --no-install-project

COPY . .
RUN uv sync --frozen --no-dev --no-editable

# ---- Final stage: runtime only (no uv, no build context) ----
FROM python:3.12-slim

ENV PYTHONUNBUFFERED=1

# Cap glibc malloc arenas and return freed memory to the OS sooner.
# Railway bills by memory per minute; these cut idle RSS 10-30MB for free.
ENV MALLOC_ARENA_MAX=2
ENV MALLOC_TRIM_THRESHOLD_=100000

WORKDIR /app

COPY --from=builder /app/.venv /app/.venv
COPY --from=builder /app/src /app/src

ENV ENV_MODE=prod
ENV HOST=0.0.0.0

# Exec the venv python directly: `uv run` would keep a ~25MB wrapper process
# resident in the container, which counts toward billed memory.
CMD ["/app/.venv/bin/python", "-m", "src.backend.main"]