Bulk API for process stats

[stephanme]

Issue

There is no bulk api to fetch process stats of multiple processes at once.

Context

cf a in a space that contains ~800 apps takes ~5min. One reason is that for every app process a single CF API request (GET /v3/processes/<process-guid>/stats) is executed to fetch the process stats.

There are additional reasons for the long execution time like cloudfoundry/cli#2733.

Possible Fix

Implement a list endpoint to fetch process stats for multiple processes, e.g.

• GET /v3/processes/stats with query params similar to GET /v3/processes, or
• add an include=stats parameter to GET /v3/processes

For good performance, it would be desirable that the cloud controller can fetch the process stats from log-cache using a bulk api as well.