在 AppEngine Python 3.7 Standard 中安装 python3-saml 失败答案

【问题标题】：python3-saml install fails in AppEngine Python 3.7 Standard在 AppEngine Python 3.7 Standard 中安装 python3-saml 失败
【发布时间】：2019-03-31 16:52:08
【问题描述】：

我在 AppEngine Python 3.7 Standard 中有一个简单的设置，只有两个文件：requirements.txt 和 app.yaml。

requirements.txt 文件是：

Flask==1.0.2
python3-saml==1.4.1

app.yaml 文件是：

runtime: python37
service: myservice

当我运行gcloud app deploy 时，出现以下错误：

ERROR: (gcloud.app.deploy) Error Response: [9] Cloud build f8eaa62c-0385-4c1a-9788-b7765313ae08 status: FAILURE.
Build error details: {"message": "`pip_download_wheels` had stderr output:\n  Failed building wheel for xmlsec\nERROR: Failed to build one or more wheels\n\nerror: `pip_download_wheels` returned code: 1", "code": 1, "type": "USER_ERROR"}.

关于如何解决此问题的任何想法？

提前谢谢你。

来自 Cloud Build 日志的相关部分：

Step #1 - "builder": Building wheels for collected packages: itsdangerous, xmlsec, MarkupSafe
Step #1 - "builder":   Running setup.py bdist_wheel for itsdangerous: started
Step #1 - "builder":   Running setup.py bdist_wheel for itsdangerous: finished with status 'done'
Step #1 - "builder":   Stored in directory: /tmp/tmpWitMY2/wheel
Step #1 - "builder":   Running setup.py bdist_wheel for xmlsec: started
Step #1 - "builder":   Running setup.py bdist_wheel for xmlsec: finished with status 'error'
Step #1 - "builder":   Complete output from command /env/bin/python3.7 -u -c "import setuptools, tokenize;__file__='/tmp/pip-wheel-o2h0m8_p/xmlsec/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/pip-wheel-229ft_of:
Step #1 - "builder":   running bdist_wheel
Step #1 - "builder":   running build
Step #1 - "builder":   running build_ext
Step #1 - "builder":   *********************************************************************************
Step #1 - "builder":   Could not find xmlsec1 config. Are libxmlsec1-dev and pkg-config installed?
Step #1 - "builder":   *********************************************************************************
Step #1 - "builder":   
Step #1 - "builder":   ----------------------------------------
Step #1 - "builder":   Running setup.py clean for xmlsec
Step #1 - "builder":   Running setup.py bdist_wheel for MarkupSafe: started
Step #1 - "builder":   Running setup.py bdist_wheel for MarkupSafe: finished with status 'done'
Step #1 - "builder":   Stored in directory: /tmp/tmpWitMY2/wheel
Step #1 - "builder": Successfully built itsdangerous MarkupSafe
Step #1 - "builder": Failed to build xmlsec
Step #1 - "builder": 
Step #1 - "builder": INFO     `pip_download_wheels` had stderr output:
Step #1 - "builder":   Failed building wheel for xmlsec
Step #1 - "builder": ERROR: Failed to build one or more wheels
Step #1 - "builder": 
Step #1 - "builder": ERROR    error: `pip_download_wheels` returned code: 1
Step #1 - "builder": INFO     pip_download_wheels took 6 seconds
Step #1 - "builder": INFO     build process for FTL image took 9 seconds
Step #1 - "builder": INFO     full build took 9 seconds
Step #1 - "builder": ERROR    `pip_download_wheels` had stderr output:
Step #1 - "builder":   Failed building wheel for xmlsec
Step #1 - "builder": ERROR: Failed to build one or more wheels
Step #1 - "builder": 
Step #1 - "builder": error: `pip_download_wheels` returned code: 1
Finished Step #1 - "builder"

【问题讨论】：

您是否已经部署了默认服务？
@BrettJ 是的，部署了一个默认服务（第一代 - Python 2.7 - 运行时）。

标签： python google-app-engine google-cloud-platform google-app-engine-python

【解决方案1】：

python3-saml 包依赖于xmlsec，这实际上是导致构建失败的原因。 This package has pre-install dependencies on system-level libraries，因此日志中有这条消息：

Could not find xmlsec1 config. Are libxmlsec1-dev and pkg-config installed?

无法在 AppEngine 标准环境中安装这些系统级软件包，相反，您需要使用 a custom runtime with AppEngine Flex，或使用不依赖于系统级软件包的 python3-saml 替代品.

【讨论】：