Windows环境部署Ozone Django服务：依赖包编译安装失败求助

背景 #

我要运行基于Django和React的Ozone服务，克隆了v8.0.0.0-GA版本的项目，进入ozone-framework-python-server目录并创建虚拟环境后，执行pip install -r requirements.txt时出现安装失败，使用的是Windows系统。

首次安装错误日志 #

Building wheels for collected packages: lxml, psycopg2-binary
  Building wheel for lxml (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py bdist_wheel did not run successfully.
  │ exit code: 1
  ╰─> [97 lines of output]

   - - -


      error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.35.32215\\bin\\HostX86\\x64\\cl.exe' failed with exit code 2
      *********************************************************************************
      Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?
      *********************************************************************************
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for lxml
  Running setup.py clean for lxml
  Building wheel for psycopg2-binary (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py bdist_wheel did not run successfully.
  │ exit code: 1

    - - - 
 
      It appears you are missing some prerequisite to build the package from source.
 
      You may install a binary package by installing 'psycopg2-binary' from PyPI.
      If you want to install psycopg2 from source, please install the packages
      required for the build and try again.
 
      error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.35.32215\\bin\\HostX86\\x64\\cl.exe' failed with exit code 2
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> psycopg2

已尝试的操作 #

• 安装了C++构建工具
• 切换到旧版本pip
• 安装wheel库
• 执行pip install --use-pep517 -r requirements.txt，依然报错，错误信息如下：

error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.35.32215\\bin\\HostX86\\x64\\cl.exe' failed with exit code 2
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for psycopg2
Failed to build lxml psycopg2
ERROR: Could not build wheels for lxml, psycopg2, which is required to install pyproject.toml-based projects

我猜测是项目长时间未更新导致版本冲突，但不知道具体解决办法。

解决方案 #

针对lxml安装失败 #

Windows下编译lxml需要依赖libxml2、libxslt等系统库，直接编译极易失败，推荐安装预编译二进制包：

• 激活虚拟环境后执行：

pip install lxml --only-binary :all:

如果requirements.txt里指定了lxml版本，补充版本号即可：

pip install lxml==<你的requirements里的版本号> --only-binary :all:

针对psycopg2安装失败 #

错误提示已明确推荐使用预编译的psycopg2-binary包，直接安装即可：

pip install psycopg2-binary

同样，若requirements.txt指定了版本，加上版本号：

pip install psycopg2-binary==<你的requirements里的版本号>

完整安装流程 #

先单独安装这两个包，再执行完整依赖安装：

pip install lxml --only-binary :all:
pip install psycopg2-binary
pip install -r requirements.txt

或者直接修改requirements.txt，将psycopg2替换为psycopg2-binary，然后执行：

pip install -r requirements.txt --only-binary lxml,psycopg2-binary

说明 #

问题根源在于旧项目的依赖包在Windows环境下从源码编译需要额外的系统依赖，而pip默认会尝试源码编译。使用预编译二进制包可以跳过编译步骤，直接完成安装，避免版本和编译环境的适配问题。

内容的提问来源于stack exchange，提问作者Horizon