[Heartbeat] Add fields to example heartbeat autodiscover usage.

[andrewvc]

It's useful when using autodiscovered endpoints to have container metadata. It's not obvious how to do this, so we document some of the fields one might use here in the docs.

This addresses a comment brought up on discuss in https://discuss.elastic.co/t/autodiscover-and-metadata/162980/1

[ruflin]

The field names use used as example are not ECS which I would not recommend.

When using autodiscovery, I would expect some of the field below to already be added. @exekias can you comment?

[andrewvc]

@ruflin it's hard to add this stuff automatically AFAICT the way the autodiscover code is written. Would love to hear @exekias ' take on it.

[exekias]

sorry for the late answer folks, this got lost in my inbox...

uhm, from what I know autodiscover should be enriching events coming from it with these fields, but that needs to be implemented by Hearbeat:

Autodiscover will pass you a meta object (common.MapStrPointer) with all the metadata, the adapter should inject this data to all the resulting events of the runner. Look at how Metricbeat is doing it, for instance:

• Get the metadata in the factory:

  beats/metricbeat/mb/module/factory.go

  Line 43 in 204264a

  func (r *Factory) Create(p beat.Pipeline, c *common.Config, meta *common.MapStrPointer) (cfgfile.Runner, error) {

• Pass it to the pipeline connector:

  beats/metricbeat/mb/module/connector.go

  Line 63 in 204264a

  DynamicFields: c.dynamicFields,

libbeat will take these fields and put them in the field. Happy to help on this if needed!

[andrewvc]

@ruflin I've updated the docs to use ECS fields.

I didn't add the labels because we don't have a great answer there. Interpolating them won't create an object, just a weird string.

I think this is a temporary solution, I agree we need a better one in the future.

[ruflin]

jenkins, test this

[andrewvc]

Closing in favor of #10258