如何在Yocto中通过python3-pip-native安装Python构建依赖

问题 #

需要构建一个依赖大量Python包的二进制文件，之前手动在构建机用pip安装所有包成功，但流程繁琐，想改用原生工具python3-pip-native管理，无需用户手动操作。但在构建系统的do_configure()阶段执行命令：

python3 -m pip install -r ${S}/scripts/constraints.txt

时出现以下错误：

Defaulting to user installation because normal site-packages is not writeable
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f26123a4a60>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/anytree/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f26123a4d90>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/anytree/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f26123a4f40>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/anytree/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f26123a50f0>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/anytree/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f26123a52a0>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/anytree/
ERROR: Could not find a version that satisfies the requirement anytree2.8.0 (from versions: none)
ERROR: No matching distribution found for anytree2.8.0
WARNING: exit code 1 from a shell command.

注：所有Python包仅用于构建，无需运行时依赖。

解决方案 #

1. 解决构建环境网络问题 #

构建系统（如Yocto/OpenEmbedded）默认构建隔离环境可能无网络访问权限，导致pip无法连接PyPI：

• 在构建配置local.conf中添加BB_NO_NETWORK = "0"，开启构建阶段网络访问（完成后可关闭以保证构建可重复性）。
• 验证构建机网络正常，在终端执行ping pypi.org确认DNS解析和网络连通性。

2. 修正pip安装路径权限 #

错误提示"normal site-packages is not writeable"，需指定具有写入权限的目录：
修改do_configure()中的命令为：

python3 -m pip install --prefix=${STAGING_DIR_HOST} -r ${S}/scripts/constraints.txt

或指定用户目录安装：

python3 -m pip install --user -r ${S}/scripts/constraints.txt

3. 采用离线预下载包构建（推荐） #

构建系统优先推荐离线构建以避免网络依赖，保证可重复性：

• 提前下载所有依赖包到本地files/python-packages目录：

  pip download -r constraints.txt -d ${S}/files/python-packages
  

• 在do_configure()中指定本地源安装：

  python3 -m pip install --no-index --find-links=${S}/files/python-packages -r ${S}/scripts/constraints.txt
  

• 在.bb文件中添加文件依赖：

  SRC_URI += "file://python-packages/"
  

4. 适配构建系统原生Python依赖管理 #

如果是Yocto/OpenEmbedded环境，更推荐通过配方管理构建依赖：

• 查找或编写目标Python包的原生配方（如python3-anytree_2.8.0.bb）。
• 在项目.bb文件中添加构建依赖：

  DEPENDS += "python3-anytree-native"
  

构建系统会自动处理依赖安装，无需手动调用pip，更符合原生工具链规范。

内容的提问来源于stack exchange，提问作者malyjak