I think this is quite a common problem 
There are soooo many CI pipelines that depend on various online services, like PyPI, Ansible Galaxy, NPM, GitHub, Docker Hub, quay.io, Maven Central, various other centralized language package repos various, various other OS package repos, various other container registries, etc. Once one of them goes down, a lot of folks are impacted because of this.
The situation would be a lot better if we’d have more pullthrough caches (which simply provide the versions they cached when the service was still up in case it’s now down), but setting these up and operating them often only becomes pressing in situations like now when something goes down.
I’m also not sure how many pullthrough caches / proxies actually exist that support Galaxy. I’m only aware of @briantist’s Galactory, an Artifactory plugin.
And of course you can host your own galaxy_ng instance, though I’m not aware that you can use it as a pullthrough cache. There’s also @sivel’s amanda, which serves a directory of collection artifacts with the Galaxy v2 API. It also needs you to manually pull the collections before they can be delivered.
Does anyone know of other solutions?