AttributeError: 'module' object has no attribute 'Cryptography_HAS_SSL_ST'

[hanzheteng]

Hi @gzhang8 ,

Thanks for your great contributions to ROS community, which indeed helped me a lot.

However, I followed your instructions and got an issue.

When running sudo -H pip install pandas jinja2 I got the traceback error

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 7, in <module>
    from pip._internal import main
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/__init__.py", line 42, in <module>
    from pip._internal import cmdoptions
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/cmdoptions.py", line 16, in <module>
    from pip._internal.index import (
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/index.py", line 15, in <module>
    from pip._vendor import html5lib, requests, six
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/__init__.py", line 86, in <module>
    from pip._vendor.urllib3.contrib import pyopenssl
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 46, in <module>
    import OpenSSL.SSL
  File "/usr/local/lib/python2.7/dist-packages/OpenSSL/__init__.py", line 8, in <module>
    from OpenSSL import crypto, SSL
  File "/usr/local/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 204, in <module>
    if _lib.Cryptography_HAS_SSL_ST:
AttributeError: 'module' object has no attribute 'Cryptography_HAS_SSL_ST'

I guess this error comes from the old version of some library. After searching on Google I found an solution. (need to check if the directory exists before removing it, in some system the path should be /usr/lib)
$ sudo rm -rf /usr/local/lib/python2.7/dist-packages/OpenSSL/
$ sudo apt install --reinstall python-openssl

This solved my problem. But after running sudo -H pip install pandas jinja2, I got an warning message in red color, though the pandas and jinja2 packages are installed successfully.

pyopenssl 17.5.0 has requirement cryptography>=2.1.4, but you'll have cryptography 1.2.3 which is incompatible.
astroid 1.6.0 has requirement enum34>=1.1.3; python_version < "3.4", but you'll have enum34 1.1.2 which is incompatible.

I am not sure if this solution will bring some other potential risks in the future.

By the way, why not put this repo into a ROS package? Then beginners can just git clone and catkin make to start their first try.

[gzhang8]

Thank you @hanzheteng for your feedback. What version of Ubuntu are you using? It seems there is a compatibility issue between packages from pip and apt. I will investigate this problem when I have time.

This repo is in this format hoping that beginners can learn a little more about how a repo is created from scratch. Do you think it helps in this way?

[hanzheteng]

I am using Ubuntu 16.04.3 LTS.

Just now I wanted to check the version of pip, and found that even pip itself cannot run, with the traceback

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 7, in <module>
    from pip._internal import main
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/__init__.py", line 42, in <module>
    from pip._internal import cmdoptions
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/cmdoptions.py", line 16, in <module>
    from pip._internal.index import (
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/index.py", line 15, in <module>
    from pip._vendor import html5lib, requests, six
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/__init__.py", line 86, in <module>
    from pip._vendor.urllib3.contrib import pyopenssl
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/urllib3/contrib/pyopenssl.py", line 46, in <module>
    import OpenSSL.SSL
  File "/usr/lib/python2.7/dist-packages/OpenSSL/__init__.py", line 8, in <module>
    from OpenSSL import rand, crypto, SSL
  File "/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 118, in <module>
    SSL_ST_INIT = _lib.SSL_ST_INIT
AttributeError: 'module' object has no attribute 'SSL_ST_INIT'

Then I solved it by sudo python -m easy_install --upgrade pyOpenSSL.

Right now the version of my pip is
pip 10.0.1 from /usr/local/lib/python2.7/dist-packages/pip (python 2.7)

I checked the source directory that, before I upgraded the openssl above, the version of pip was also 10.0.1. pip doesn't work due to the problem of openssl.

I have a snapshot in Virtualbox created before running sudo -H pip install pandas jinja2. I will check it later, just leaving the prompt message here for your information.