Database Maintenance Mode and Operations

[cd-rite]

Allow App managers to put the app into a "Maintenance Mode" limiting app functionality for other users, but enabling new maintenance features.

The once enabled, /op/maintenance endpoints will let admins:

• invoke OPTIMIZE TABLES

• invoke ANALYZE TABLES

• run statements that re-calculate metrics (with granularity?)

• run statements that populate our materialized views (current_rev, default_rev)

• dump select data to file (ie. AppData)

• push data from a file (ie. AppData)

• run statements that restore disabled objects

• run statements that performantly delete disabled objects

• delete orphaned reviews

• force history deletions

• export history?

• offer MySQL SELECT statements

• See raw endpoint responses

• Enable Swagger UI

• get maintenance mode status (operations in progress, etc)

• Request END MAINTENANCE MODE (account for ops in progress)

• Not all of the above may require full "maintenance mode" limiting access for other users.

Consider:
Allowing access to STIG endpoints for Reference STIG imports, allowing unfettered metrics recalculation (in lieu of background metrics calculations)

Client behavior on invocation of maintenance mode:
App Managers:
Any app Admin can use "maintenance" features once mode is invoked.
Restricted Ext client or full client, any operation allowed?
Leaning towards - Entirely new client with limited feature set.

When does Maintenance Mode end?
Initially - no timeout, must be ended by app admin.
Alternate "permanent" entry to maintenance mode - set w Envvar

Others:
Alternate client - Simple "STIGMan is in maintenance mode. Invoked by: XXXXX" message.
Standard Error handler - intercept "maintenance mode" message and invoke special handling (suggest reloading app, etc.)

API
In maintenance mode:
return 503s based on user privilege (populated by "maintenance mode" message).
intercept in auth handling - user must have "admin" privilege to process any request

Feature:
Take "snapshot" of current state of collection(s) Reviews/metrics, or parts thereof.