inputs.mongodb : adding metrics for member and replica-set avg health

[svenburkard]

Feature Request

The MongoDB input plugin offers currently no metrics to detect the health state of a replica-set.

Proposal:

Collecting MongoDB replica-set health metrics

Current behavior:

No MongoDB replica-set health metrics available

Desired behavior:

• Collecting a replica-set health metric of the MongoDB cluster node your Telegraf agent is connected to
• Collecting a replica-set health average metric, to detect if another member is unhealthy from the perspective of another member and also to see how bad the replica-set health is

Use case:

If Telegraf would offer this mentioned MongoDB replica-set health metrics, you would get everything needed to build monitoring alerts on top of this data.