The article hints that cache invalidation is driven by the layers higher up the stack, relying on domain knowledge. For example, the application may decide tha

The article hints that cache invalidation is driven by the layers higher up the stack, relying on domain knowledge. For example, the application may decide that all files are read-only, until expired a few days later. Not clear about write-cache. My guess is that you will want some sort of redundancy when caching writes, so this goes beyond a library and becomes a service. Unless the domain level can absolve you of this concern by having redundancy elsewhere in the system (eg feed data from a durable store and replay if you lost some s3 writes).