Index `kibana_settings` docs for Kibana X-Pack Monitoring

[ycombinator]

As a follow up to elastic/kibana#20577 and as a part of making progress on #7035, we need a settings metricset in the kibana metricbeat module. This metricset would poll the Kibana settings API and ship its results into .kibana-monitoring-6-* indices provided xpack.enabled: true is set in the module's configuration.

[ycombinator]

@ruflin I would like to make this metricset xpack-only (i.e. it only fetches and ships if xpack.enabled: true), since this information is only really needed by X-Pack Monitoring to make Cluster Alerts work today.

In the mid/long term Cluster Alerts will be driven entirely from within Kibana and will not rely on settings documents in .monitoring-kibana-6-* indices. At that time we can remove this metricset (and the associated settings API in Kibana).

Thoughts?

[ruflin]

To not have to create a metricset which is X-Pack only I wonder if we could merge it into the x-pack stats metricset. Meaning we by default it sends 2 events.

[ycombinator]

I think we could do that but the stats metricset would need to make two API calls to Kibana when xpack.enabled: true: one to <kibana host:port>/api/stats and one to <kibana host:port>/api/settings.

I'm not entirely sure how to make this happen, given how we create a http helper from a metricset object by calling helper.NewHTTP in stats.New. Do we create two http helpers in stats.New? Or do we keep just the one helper but set/reset its URL in stats.Fetch? Or something else? Maybe there an existing metricset that does this sort of thing (makes two API calls) I could look at?

[ruflin]

I would opt for the two request. We do this trick also for Elasticsearch where we need to fetch additional info for the event. It's a bit hacky but it works.