Python Pip broken with sys.stderr.write(f"ERROR: {exc}")

Question

On fresh Vagrant VM using box bento/centos-7 the following commands corrupt my pip installation:

yum update
yum install epel-release -y
yum install python-pip -y
/usr/bin/pip2 install --upgrade pip setuptools pyOpenSSL psycopg2-binary lxml

This fails at the end with

  Downloading https://files.pythonhosted.org/packages/84/48/5c99d8770fd0a9eb0f82654c3294aad6d0ba9f8600638c2e2ad74f2c5d52/setuptools-52.0.0.tar.gz (2.1MB)
    100% |████████████████████████████████| 2.1MB 821kB/s
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "setuptools/__init__.py", line 16, in <module>
        import setuptools.version
      File "setuptools/version.py", line 1, in <module>
        import pkg_resources
      File "pkg_resources/__init__.py", line 1367
        raise SyntaxError(e) from e
                                ^
    SyntaxError: invalid syntax

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-GZrC3W/setuptools/
You are using pip version 8.1.2, however version 21.0 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

If I then upgrade Pip I notice that my Python is broken. After that all pip commands end with SyntaxError

[root@bkd-openam ~]# pip install --upgrade pip
Collecting pip
  Using cached https://files.pythonhosted.org/packages/9e/24/bc928987f35dd0167f21b13a1777c21b9c5917c9894cff93f1c1a6cb8f3b/pip-21.0.tar.gz
Installing collected packages: pip
  Found existing installation: pip 8.1.2
    Uninstalling pip-8.1.2:
      Successfully uninstalled pip-8.1.2
  Running setup.py install for pip ... done
Successfully installed pip-21.0
[root@bkd-openam ~]# /usr/bin/pip2 install --upgrade pip setuptools pyOpenSSL psycopg2-binary lxml
Traceback (most recent call last):
  File "/usr/bin/pip2", line 9, in <module>
    load_entry_point('pip==21.0', 'console_scripts', 'pip2')()
  File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 378, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 2566, in load_entry_point
    return ep.load()
  File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 2260, in load
    entry = __import__(self.module_name, globals(),globals(), ['__name__'])
  File "/usr/lib/python2.7/site-packages/pip/_internal/cli/main.py", line 60
    sys.stderr.write(f"ERROR: {exc}")
                                   ^
SyntaxError: invalid syntax

Why is this? Is this a known issue with Python? How do I fix this?

BTW, CentOS 7 is a given, we cannot upgrade to CentOS 8 at this point. Also, we are using Ansible so using virtualenv I think for target nodes is recommended against by the Ansible community.

We can install Python 3 of course on target nodes but not all Ansible code is available for combination Python 3 with CentOS 7.

Can we use Pip 20? We would like to upgrade to the most recent version of Pip that still works and I think that is Pip 20. How do I prevent upgrade to Pip 21?

Answer 1

You can get an older version (2.7) of get-pip.py

curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py

In my opinion, you should create a python2 virtualenv and install your python2 package in it, as well as pip2. For example, when I installed cuckoo sandbox, I did it like this:

virtualenv --python=python2 cuckoo/   # make your virtualenv folder with python2
cd cuckoo
source bin/activate
curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py   # get pip for python2
python2 get-pip.py        # install pip in your virtualenv
pip install cuckoo       # install your python2 package

Hope it will help.