I'm doing a talk at Next tomorrow about just that. For now you are probably better of using Ruby on App Engine, assuming you need to use redis as a cache. Another new feature that we launched today is VPC Connectors, which allow Cloud Functions and App Engine to connect to servers/services in a VPC.

Cloud Run will have support VPC Connectors soon (it is supported, we just haven't wired up the API/UI). After that, its your choice, they run on similar infrastructure so you just need to decide if you want to live in containerland or source code land.

I'll post the example source code here tomorrow after the talk (still tweaking it).

OK thanks! How about persisting files (which actually isn't possible on Heroku but we would like to persist files on disk for simplicity so are debating about just using AWS)?

We provide an in-memory writable filesystem (e.g. you want to do file transformations) but it's not persistent across all instances. We're looking into Filestore integration for a mountable NFS product, though as mentioned in another comment about that, reading is easy but writing is hard.

Why is writing hard? We already use Filestore across multiple VMs in read-write mode. We ensure that writes are unique i.e no two machines will use the same filename. There are also no file modifications.