Add method for deduping images

[IamTheFij]

This is helpful with Nomad because some images end up used as sidecars for many jobs. Also periodic jobs spawn many tasks with the same image.

[crazy-max]

Thanks but I think this should be something done for all providers related to #342

[IamTheFij]

I was reluctant to make changes to other providers I'm less familiar with, but I think this is fairly safe. Thoughts on doing it all in one PR or splitting it?

[IamTheFij]

I just added it to all of them now.

[IamTheFij]

I was just thinking that this won't dedupe across providers, but that's probably not an issue and also not nearly as easy since it appears that there is no central aggregation of model.Images before checking for updates.

[crazy-max]

I was just thinking that this won't dedupe across providers, but that's probably not an issue and also not nearly as easy since it appears that there is no central aggregation of model.Images before checking for updates.

Yes indeed. At first I was just thinking about dedup notifications but it would be better to dedup image analysis across all providers. One way would be to have another job matrix to just collect tags we want to analyze and dedup those before checking for updates. We would need to make sure metadata are handled during dedup so it would analyze an image once but would potentially send multiple notifications if metadata are different. I will think about it a bit more.

[IamTheFij]

What do you think about merging this now while determining if a broader refactor is in order? It seems like an improvement over status quo and probably few users use multiple providers.

[IamTheFij]

Also, not sure what happened with the test run… I added a test for everything I wrote. I can’t tell if the change actually results in lower coverage or if some flake made the tests abort and resulted in reporting lower coverage.