Define roles in Cassandra

[seanshahkarami]

For safety reasons, I think it makes sense to define a few different roles for Cassandra use. A few examples are:

• Select from sensor data only role. This could be used by services which only need to present the data.
• Select from all tables. This could be used by services which need to export all tables for backups.
• Select / insert into sensor data tables. This could be used for ETL services.
• Admin. The name says it all.

These could help limit the damage that could be done if a service was compromised or improperly designed. This could also help prepare us for a design where the database is easily provisioned into different production, development and testing keyspaces.

[seanshahkarami]

I learned how to configure authentication and authorization in Cassandra this evening. I'd like to try to get that in the next revision to allow for very tight control over which processes are allowed to access what parts of the database. (No more risky table drops, inserts, deletes, etc...)