Integrate with Redis for rate limiting / quota

[douglas-reid]

Tracking issue (from spreadsheet).

[rshriram]

Is this spreadsheet open for others? Any additional details?

What is the rationale for having yet another key value datastore in the control plane ? Why not use TPRs?

We now have three different configuration stores broadly speaking. TPR, config maps (k8s specific) and then redis (platform independent). Has any consideration been given to the proliferation of data stores in the config plane itself?

[douglas-reid]

Please ignore all mentions of spreadsheet here. It was a temporary holding place for things that were getting transferred to github issues. It isn't worth spending any time thinking about.

Here, redis is being used for quota enforcement. It does indeed reflect another data store, but I expect that once the config API is ready and supported, the storage of the underlying config storage will itself migrate towards redis (and away from TPR and configmaps and anything platform-specific).

@mandarjog can speak more to the plans here, but indeed, we want to reduce the number of config vectors.

[chowchow316]

#435