Python Pip broken wiith sys.stderr.write(f“ERROR: {exc}”)

问题

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 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?

回答1:

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

curl https://bootstrap.pypa.io/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/2.7/get-pip.py --output get-pip.py   # get pip for python2
python get-pip.py        # install pip in your virtualenv
pip install cuckoo       # install your python2 package

Hope it will help.

回答2:

This problem has to do with the fact that Python 2.7 reached end of its life and that the PIP community dropped support for it this month.

PIP displays deprecation notices such as

DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support pip 21.0 will remove support for this functionality.

To fix this and continue with unsupported Python 2.7 you should not upgrade to the latest pip version but to a version < 21.

pip install --upgrade "pip < 21.0"

回答3:

As PIP dropped support for Python 2.7 in result we are facing the above mentioned issue, following are the commands which actually worked for me on Ubuntu.

sudo apt-get remove --purge python-pip
sudo apt-get autoremove
sudo rm -f /usr/local/bin/pip
sudo easy_install pip==20.3.4
pip --version

Output: pip 20.3.4

Same can be achieved for CentOS by changing package manager name.

回答4:

If this logic is used in a (e.g.) Github Actions matrix of different Python versions, the following bash snippet will determine if pip should be updated before pip 21.0 or not. For instance, Python 3.5 should not update beyond pip 21.0, but Python 3.6 can use more recent versions.

use_pip_lt_21=`python -c "import sys; print(sys.version_info[:2] < (3, 6))"`
if [ $use_pip_lt_21 = "True" ]; then
  pip="pip < 21.0"
else
  pip="pip"
fi
pip install --disable-pip-version-check --upgrade "$pip"

来源：https://stackoverflow.com/questions/65896334/python-pip-broken-wiith-sys-stderr-writeferror-exc

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python

pip