Problem: For some reason trying to pip install virtualenvwrapper is causing my system to attempt directly reaching the Internet, bypassing my nexus caching server.
Basics of environment:
CentOS Linux release 7.3.1611 (Core) behind firewall restricting all outbound traffic except to nexus proxy server.
pip 9.0.1 from /usr/lib/python2.7/site-packages (python 2.7)
index = https://mynexusserver.local/repository/python-group/pypi
index-url = https://mynexusserver.local/repository/python-group/simple
cert = /etc/pki/tls/mynexusserver.cert.pem
Expected Behavior: pip install virtualenvwrapper to proxy through my nexus server and install virtualenvwrapper without issue.
Actual Behavior: pip install virtualenvwrapper starts by downloading the virtualenvwrapper package correctly (it seems), but then hangs during the dependency resolution.
Workaround: If I temporarily allow my testbed outbound 443 access directly to the Internet, the dependencies are pulled from a standard PyPi server, and then all of the packages are downloaded via my nexus proxy as expected. This would seem to indicate it is only the dependency resolution that actually requires access to the Internet.
Question: Why does the virtualenvwrapper package require direct Internet access to resolve it's dependencies? No other package I've attempted to install has this behavior.
Hoping someone has an obvious answer I've overlooked.