Remap OTel hostmetrics to Elastic metrics

[lahsivjar]

The PR uses the library opentelemetry-lib to remap metrics produced by hostmetricsreceiver to Elastic metrics that could power the curated UIs.

Example OTel collector configuration required to get the remapping working

receivers:
  hostmetrics:
    collection_interval: 10s
    scrapers:
      load:
      cpu:
        metrics:
          system.cpu.utilization:
            enabled: true
          system.cpu.logical.count:
            enabled: true
      memory:
        metrics:
          system.memory.utilization:
            enabled: true
      network:
      process:
        metrics:
          process.threads:
            enabled: true
          process.open_file_descriptors:
            enabled: true
          process.memory.utilization:
            enabled: true
          process.disk.operations:
            enabled: true
      processes:

exporters:
  otlphttp:
    endpoint: http://192.168.0.44:8200
    tls:
      insecure: true
  debug:
    verbosity: detailed

processors:
  resourcedetection/system:
    detectors: ["system"]
    system:
      hostname_sources: ["os"]

service:
  pipelines:
    metrics:
      receivers: [hostmetrics]
      processors: [resourcedetection/system]
      exporters: [otlphttp, debug]

Related issues

• https://github.com/elastic/opentelemetry-dev/issues/217
• https://github.com/elastic/opentelemetry-dev/issues/180

[lahsivjar]

[For reviewers] This code is required to make sure that the remapped OTel metrics end up in the app datastream instead of the internal datastream.

[endorama]

Left a blocking comment and some minor non-blocking discussion points.

[axw]

Code LGTM, just wondering about the event.provider check. I think we should come to an agreement on that before merging.

[endorama]

Looks good to me!