Add 404 / failed install statistics

[Julian]

Hi!

It might be interesting to be able to query through failed installation data, if such a thing is possible.

I.e. -- to view pip install foo by volume, for foo a non-existing package, or existing package with no uploaded files.

[di]

This would probably also provide some interesting data on potential typosquats.

[pradyunsg]

I think it would be possible to do this, using the simple API stats and download stats, to determine names that were hit on the simple index but not downloaded?

That’s assuming PyPI is sending in a note to linehaul even when it sends a 404. Not sure if that’s the case though.