[OAM] Introduce API in asset_manager plugin to return service assets

[kpatticha]

Context

In the first iteration, we retrieved the assets within APM but the assets should be retrieved by a central plugin and not within every plugin.

The asset_manager seems the right place to expose the API related to assets. While the asset_manager already expose APIs, they are not used anywhere so probably it should be fine to clean up the existing code and introduce a simpler API

Requirements

Introduce a getServices(start, end, kuery) service that returns the service assets from the assets indices

Consumer:

• APM

and it expects the minimum required fields to be

most likely we'll need agent.name

{
  "services": [
    {
      "asset": {
        "signalTypes": {
          "asset.traces": true,
          "asset.logs": true
        },
        "identifyingMetadata": [
          "service.name"
        ]
      },
      "service": {
        "name": "multisignal-service",
        "environment": "testing"
      }
    }
  ]
}

Query used in APM - https://github.com/elastic/kibana/pull/181842/files#diff-2f7f5edd98cf9152857697cb525eeb2765db8295de3efc9bcbaff602fb14063aR1

Pending

• UI relies onagent.name to display the agent icon.

stretch goal

• Use ES|QL to fetch the service assets

Note

• minimum required field could change as we finalise OAM

[elasticmachine]

Pinging @elastic/obs-ux-infra_services-team (Team:obs-ux-infra_services)

[botelastic]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[cauemarcondes]

This is no longer relevant.