It sounds like it provides a nice s3 cache system for your backend. That is, it matches every s3 call to be a simple drop in request replacement powered by redis for caching.
It says that it only stores metadata locally not objects themselves (although it could probably have an option for that too and serve as a general S3 cache).
Nice effort, Redis is perfectly fine but I believe that the storage layer should be somehow more separated in case someone wants another type of storage, e.g. in-memory SQLite is adequate and already installed in most systems.
I agree about with you about a replacement for redis. Maybe it's only me, but I seem to be relying too much on redis for simple things. I feel that soon enough I'll need 4 independent redis servers for my production environment.
That's of course tongue-in-cheek, but there's a degree of seriousness.
Yes, I think that's the gist of it. It looks like it assumes it has seen every call to the bucket it's working on though. So to start using it with an existing bucket, you'd have to warm up the Redis cache by downloading all metadata from the bucket?
You can call the .sync() function on an S3Connection or a Bucket object. The MimicDB instance is populated with the current data on S3. Also, syncing is stateless, so you can call it anytime to insure consistency.
It looks like a drop-in replacement for boto's S3 interface, so if you're already using that, you can probably just change the imports to refer to MimicDB.
Disclaimer: I'm tired and may have read it wrong.