hostmetricsreceiver: refactor load metrics to use generated metrics

[mstumpfx]

Description: Adding the load metrics to the metadata.yaml, and refactoring the hostmetricreceivers load metrics to use generated metrics

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Mark Stumpf (af54038)

[codecov]

Codecov Report

Merging #2375 (3fddb38) into master (6f772bf) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2375      +/-   ##
==========================================
- Coverage   92.01%   92.00%   -0.01%     
==========================================
  Files         273      272       -1     
  Lines       15434    15405      -29     
==========================================
- Hits        14202    14174      -28     
  Misses        850      850              
+ Partials      382      381       -1     

Impacted Files	Coverage Δ
...eiver/internal/scraper/loadscraper/load_scraper.go	100.00% <100.00%> (ø)
internal/data/bytesid.go	76.92% <0.00%> (-4.03%)	⬇️

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[jrcamp]

lgtm

[tigrannajaryan]

1. Does this need to be exported? (It was not previously).
2. Is it possible to come up with a less generic name? Looking at the name Metric I have a hard time understanding what it is supposed to do.

[mstumpfx]

@tigrannajaryan I had changed it to exported to be able to pass through the interface so the Init() function could be called generically -

opentelemetry-collector/receiver/hostmetricsreceiver/internal/scraper/loadscraper/load_scraper.go

Lines 69 to 76 in db35667

	initializeLoadMetric(metrics.At(0), metadata.Metrics.SystemCPULoadAverage1m, now, avgLoadValues.Load1)
	initializeLoadMetric(metrics.At(1), metadata.Metrics.SystemCPULoadAverage5m, now, avgLoadValues.Load5)
	initializeLoadMetric(metrics.At(2), metadata.Metrics.SystemCPULoadAverage15m, now, avgLoadValues.Load15)
	return metrics, nil
	}
	func initializeLoadMetric(metric pdata.Metric, metricDescriptor metadata.Metric, now pdata.TimestampUnixNano, value float64) {
	metricDescriptor.Init(metric)

I think pattern will occur more as more of the metrics in the receiver are refactored to be based off the generated metrics. The previous use cases were only for the scrapers that emitted a single metric.

I'm indifferent towards the name - MetricIntf? MetricFactory? GeneratedMetric?

[tigrannajaryan]

OK, understood re exporting.

As for the name, please use something that reflects the purpose. I do not quite understand what it does to suggest a good name. The generic name Metric does not help me to understand what it is doing.

If unsure keep it unchanged.

[mstumpfx]

I reverted the name back to MetricIntf for now and added a comment above to describe it.