# 分层构建：避免依赖第三方基础镜像（例如 tiangolo）拉取失败
FROM python:3.11-slim

WORKDIR /app

ENV PYTHONDONTWRITEBYTECODE=1
ENV PYTHONUNBUFFERED=1

# 依赖层：只有 requirements 变更时才重建
COPY requirements.txt /app/requirements.txt
RUN pip install --no-cache-dir -r /app/requirements.txt

# 代码层：仅此层会随业务代码变更而重建
COPY backend /app/backend

EXPOSE 8000

# SQLite 对并发写不友好，单进程即可；如需生产多 worker 可在 compose 里调整
CMD ["uvicorn", "backend.app.main:app", "--host", "0.0.0.0", "--port", "8000"]