Support options, extra indexes and VCS installation in requirements for dep resolution

[pombredanne]

pip files can contains various "options" such as index URLs and VCS. We should support these:

• Support requirements file with --extra-index-url : We planned to support alright multiple --index-url in the "dad" CLI. There can also be --extra-index-url in the requirements file. #20
• Support requirements file with editable install with -e where we should possible try to follow the local path reference and/or a remote VCS
• Support requirements file with with VCS URLs

[bennati]

Is that right that currently only --extra-index-url is supported and --index-url is not? See https://github.com/nexB/python-inspector/blob/102ef9b46caf8758e17dcc46af316647fb75a5fb/src/python_inspector/api.py#L146

[dimitris-iliou]

We need to configure pip to use a specific proxy URL. I’ve already set up the local pip.conf, and when running ORT and printing those files to verify, the settings correctly reflect our preferred index-url and hostname.
However, all pip packages are still showing the default URL as their source artifact.

Let me know if there’s anything else we should configure or investigate further.