Not able to install Python packages [SSL: TLSV1_ALERT_PROTOCOL_VERSION]

Question

I am trying to install a Python library using pip, getting an SSL error:

~/projects/base  pre-master±  pip install xdict

Collecting xdict
  Could not fetch URL https://pypi.python.org/simple/xdict/: There was a problem confirming the ssl certificate: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:590) - skipping
  Could not find a version that satisfies the requirement xdict (from versions: )
No matching distribution found for xdict

pip version: pip 9.0.1

How do I fix this error?

Answer 1

Upgrade pip as follows:

curl https://bootstrap.pypa.io/get-pip.py | python

Note: You may need to use sudo python above if not in a virtual environment.

(Note that upgrading pip using pip i.e pip install --upgrade pip will also not upgrade it correctly. It's just a chicken-and-egg issue. pip won't work unless using TLS >= 1.2.)

As mentioned in this detailed answer, this is due to the recent TLS deprecation for pip. Python.org sites have stopped support for TLS versions 1.0 and 1.1.

From the Python status page:

Completed - The rolling brownouts are finished, and TLSv1.0 and TLSv1.1 have been disabled. Apr 11, 15:37 UTC

For PyCharm (virtualenv) users:

1. Run virtual environment with shell. (replace "./venv/bin/activate" to your own path)

   source ./venv/bin/activate
   

2. Run upgrade

   curl https://bootstrap.pypa.io/get-pip.py | python
   

3. Restart your PyCharm instance, and check your Python interpreter in Preference.