bug fix

backend/Dockerfile

@@ -8,7 +8,8 @@ WORKDIR /app
 ENV PYTHONUNBUFFERED=1 \
     PYTHONDONTWRITEBYTECODE=1 \
     PIP_NO_CACHE_DIR=1 \
-    PIP_DISABLE_PIP_VERSION_CHECK=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1 \
+    PIP_DEFAULT_TIMEOUT=120
 
 # 替换为阿里云 Debian 镜像源（国内加速）
 RUN sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list.d/debian.sources && \
@@ -16,7 +17,7 @@ RUN sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list.d/debia
 
 # 安装系统依赖（含 WeasyPrint 渲染库 + CJK/等宽系统字体）
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    gcc \
+    build-essential \
     default-libmysqlclient-dev \
     pkg-config \
     libpango-1.0-0 \
@@ -34,8 +35,12 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 # 复制依赖文件
 COPY requirements.txt .
 
+# 升级打包工具，减少 PEP517/源码构建失败
+RUN pip install --no-cache-dir --upgrade pip setuptools wheel -i https://pypi.tuna.tsinghua.edu.cn/simple
+
 # 安装 Python 依赖
-RUN pip install --no-cache-dir -r requirements.txt -i https://pypi.tuna.tsinghua.edu.cn/simple
+RUN pip install --no-cache-dir -r requirements.txt -i https://pypi.tuna.tsinghua.edu.cn/simple || \
+    pip install --no-cache-dir -r requirements.txt -i https://pypi.org/simple
 
 # 复制项目文件
 COPY . .