Configure and customize pip
You can customize your pip.conf to point to a custom pypi repository
Sometimes a pip user may want to install a python package from a repository other than http://pypi.python.org/simple/.
ONAP has a staging repository in nexus3 for example at https://nexus3.onap.org/repository/PyPi.staging/.
By default, when you "pip install" it pulls from the public pypi repo, but if you want to pull from a custom repo there are 3 ways to do so (listed in order of precedence):
By passing a CLI flag to specify a custom index url
pip install -i/--index-url <url> <package>
By setting an environment variable
export PIP_INDEX_URL=<url> pip install <package>
By specifying in a custom pip.conf file
[global] timeout = 60 index-url = https://nexus3.onap.org/repository/PyPi/simple
Exhaustive documentation on pip configuration can be found here https://pip.pypa.io/en/stable/user_guide/#config-file