The check_external_repos option for Koji checks the timestamp on external repos by using Requests to fetch the repo's repomd.xml file. This works fine if the repo is an http:// or https:// URL, but fails for local RPM repositories with a file:// URL. This happens because the Requests library in its base configuration only handles HTTP urls. As I see it this could be solved one of two ways.

One solution would be to use a transport adapter for Requests, which would allow it to handle other kinds of URLs. A Requests transport adapter for file:// urls is already available in Fedora and downstream distributions, so one solution to this problem could be to add that package as a dependency and mount it to the Requests session for Kojira.

The other solution would be to remove Requests from Kojira entirely, and just use the stdlib's urllib.request.urlopen, which does correctly handle file:// URLs. Fetching the repo metadata is the only use of requests within kojira, so we could actually just remove that import entirely if we went about it this way.

I'd like to contribute this fix if that's alright?
If anybody has thoughts about which of these approaches to take I'm open to suggestions.