Log reaped cursor Information (mloginfo --cursors)

[mitesh-gosavi]

Expected behavior

Sometimes, queries fail because a cursor cannot be found. It would be really useful to see in the mongod logs when a cursor is reaped, to determine if that cursor was lost due to timeout.
We should consider parsing the logs to export the information when a cursor is reaped (and not when it is merely marked for deletion, which is annoying for pinned cursors, which will not be timed out).

Actual/current behavior

So far, mtools does not parse any reaped cursor information; however, we can add feature to it to display the reaped cursor information.

Steps to reproduce the actual/current behaviour

The milestone is to parse the information related to the cursors which were reaped out for exceeding the timeout limit.
The parser on receiving the --cursor flag can search for log lines containing the “Cursor id” token. On encountering the token, it can parse the cursor id and reaped-out time using following tokens: timed out, idle since.

Environment

Software	Version
mtools	1.5.3
MongoDB server	4.0.10