Persitent archiving of images and/or recipes

[pauleve]

In addition to mirror on github packages, we should consider persistent archiving of images.

Currently, I see two approaches:

• backup the full images on Zenodo: quite easy to realize (docker can export the full image as a tar file), although I'm not sure how to automatize that. We can then add an option to the colomoto-docker program to fetch an image from zenodo
• alternatively/in parallel, ensuring that all images can be built over time (Periodic testing for building old images #76) sounds more lightweight (note that zenodo allows up to 50GB per record, so we are far from this limit). The main issue is then to have a persistent backup of conda packages, as they may be deleted or moved to other labels by their maintainers. A first step would be to have a colomoto-history conda channel and copy all packages there to ensure we can fetch them later. But then, I don't know how reliable is anaconda.org over time.

[pauleve]

Here is the doc to automate the upload on zenodo: https://developers.zenodo.org/#quickstart-upload
I can implement that during September, it sounds the most straightforward way to reliably archive our images.

[aurelien-naldi]

Archiving on zenodo sounds like a great idea!
Maybe we should tag some images as "long term" to reduce a bit the load?

[pauleve]

Superseeded by #141 for archiving with zenodo and #92 for building (latter has a very low priority)