指定 python 版本时 pip 和 virtualenv 的问题

Question

我正在使用 virtualenv (1.11.6) 来管理我的 python 项目，我创建了一个新项目，但我注意到它使用的是旧的 python 版本（2.7.2 而不是 2.7.8 )，所以我使用 -p 选项重新创建了一个 virtualenv：

virtualenv -p /opt/local/bin/python ENV

现在项目使用 python 2.7.8，但如果我尝试使用 pip 1.5.6（例如 scrapy）安装任何 python 库，我会得到 ​​p >

命令 python setup.py egg_info 失败，错误代码 1

如果我在没有指定 python 版本的情况下创建 virtualenv 就不会发生这种情况......这种行为的原因可能是什么？如何使用我选择的 python 版本创建 virtualenv，没有问题？

ps：我使用的是 OS X，并且我使用 macports 安装了 python 2.7.8

编辑： 这个问题在某种程度上与scrapy所依赖的密码库有关：

running build_ext

building '_Cryptography_cffi_4ed9e37dx4000d087' extension

creating /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography

creating /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography/hazmat

creating /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography/hazmat/bindings

creating /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography/hazmat/bindings/__pycache__

/usr/bin/clang -fno-strict-aliasing -fno-common -dynamic -pipe -Os -fwrapv -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/opt/local/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.c -o /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.o

/usr/bin/clang -bundle -undefined dynamic_lookup -L/opt/local/lib -Wl,-headerpad_max_install_names -L/opt/local/lib/db46 /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.o -lcrypto -lssl -o /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.so

Traceback (most recent call last):

  File "<string>", line 17, in <module>

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/setup.py", line 174, in <module>

    "test": PyTest,

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/core.py", line 151, in setup

    dist.run_commands()

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py", line 953, in run_commands

    self.run_command(cmd)

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py", line 972, in run_command

    cmd_obj.run()

  File "<string>", line 15, in replacement_run

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 186, in find_sources

    mm.run()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 246, in run

    self.add_defaults()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 282, in add_defaults

    sdist.add_defaults(self)

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/lib/python2.7/site-packages/setuptools/command/sdist.py", line 167, in add_defaults

    build_py = self.get_finalized_command('build_py')

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/cmd.py", line 312, in get_finalized_command

    cmd_obj.ensure_finalized()

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized

    self.finalize_options()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/lib/python2.7/site-packages/setuptools/command/build_py.py", line 26, in finalize_options

    orig.build_py.finalize_options(self)

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/command/build_py.py", line 46, in finalize_options

    ('force', 'force'))

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/cmd.py", line 298, in set_undefined_options

    src_cmd_obj.ensure_finalized()

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized

    self.finalize_options()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/setup.py", line 88, in finalize_options

    self.distribution.ext_modules = get_ext_modules()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/setup.py", line 68, in get_ext_modules

    OpenSSLBinding().ffi.verifier.get_extension(),

  File "cryptography/hazmat/bindings/openssl/binding.py", line 89, in __init__

    self._ensure_ffi_initialized()

  File "cryptography/hazmat/bindings/openssl/binding.py", line 109, in _ensure_ffi_initialized

    libraries=libraries,

  File "cryptography/hazmat/bindings/utils.py", line 80, in build_ffi

    extra_link_args=extra_link_args,

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cffi-0.8.6-py2.7-macosx-10.8-x86_64.egg/cffi/api.py", line 340, in verify

    lib = self.verifier.load_library()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cffi-0.8.6-py2.7-macosx-10.8-x86_64.egg/cffi/verifier.py", line 75, in load_library

    return self._load_library()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cffi-0.8.6-py2.7-macosx-10.8-x86_64.egg/cffi/verifier.py", line 151, in _load_library

    return self._vengine.load_library()

  File "/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cffi-0.8.6-py2.7-macosx-10.8-x86_64.egg/cffi/vengine_cpy.py", line 149, in load_library

    raise ffiplatform.VerificationError(error)

cffi.ffiplatform.VerificationError: importing '/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.so': dlopen(/Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.so, 2): Symbol not found: _CRYPTO_malloc_debug_init

  Referenced from: /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.so

  Expected in: flat namespace

 in /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_4ed9e37dx4000d087.so

----------------------------------------
Cleaning up...
Command python setup.py egg_info failed with error code 1 in /Users/davidezanotti/PycharmProjects/scrapy_test/ENV/build/cryptography
Storing debug log for failure in /Users/davidezanotti/.pip/pip.log

似乎我错过了一些开发工具或类似的东西......但我不明白为什么我创建一个环境而不指定python版本就可以成功安装它：/

Answer 1

virtualenv 和 python 版本的问题有时与库相关联，python 包具有依赖关系。

This post 描述了如何解决 cryptography 依赖的问题。