func remapMemoryMetrics()

in remappers/hostmetrics/memory.go [26:151]
120 lines of code
21 McCabe index (conditional complexity)

func remapMemoryMetrics(
	src, out pmetric.MetricSlice,
	_ pcommon.Resource,
	mutator func(pmetric.NumberDataPoint),
) error {
	var timestamp pcommon.Timestamp
	var total, free, cached, usedBytes, actualFree, actualUsedBytes int64
	var usedPercent, actualUsedPercent float64

	for i := 0; i < src.Len(); i++ {
		metric := src.At(i)
		switch metric.Name() {
		case "system.memory.usage":
			dataPoints := metric.Sum().DataPoints()
			for j := 0; j < dataPoints.Len(); j++ {
				dp := dataPoints.At(j)
				if timestamp == 0 {
					timestamp = dp.Timestamp()
				}

				value := dp.IntValue()
				if state, ok := dp.Attributes().Get("state"); ok {
					switch state.Str() {
					case "cached":
						cached = value
						total += value
					case "free":
						free = value
						usedBytes -= value
						total += value
					case "used":
						total += value
						actualUsedBytes += value
					case "buffered":
						total += value
						actualUsedBytes += value
					case "slab_unreclaimable":
						actualUsedBytes += value
					case "slab_reclaimable":
						actualUsedBytes += value
					}
				}
			}
		case "system.memory.utilization":
			dataPoints := metric.Gauge().DataPoints()
			for j := 0; j < dataPoints.Len(); j++ {
				dp := dataPoints.At(j)
				if timestamp == 0 {
					timestamp = dp.Timestamp()
				}

				value := dp.DoubleValue()
				if state, ok := dp.Attributes().Get("state"); ok {
					switch state.Str() {
					case "free":
						usedPercent = 1 - value
					case "used":
						actualUsedPercent += value
					case "buffered":
						actualUsedPercent += value
					case "slab_unreclaimable":
						actualUsedPercent += value
					case "slab_reclaimable":
						actualUsedPercent += value
					}
				}
			}
		}
	}

	usedBytes += total
	actualFree = total - actualUsedBytes

	remappedmetric.Add(out, mutator,
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.total",
			Timestamp: timestamp,
			IntValue:  &total,
		},
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.free",
			Timestamp: timestamp,
			IntValue:  &free,
		},
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.cached",
			Timestamp: timestamp,
			IntValue:  &cached,
		},
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.used.bytes",
			Timestamp: timestamp,
			IntValue:  &usedBytes,
		},
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.actual.used.bytes",
			Timestamp: timestamp,
			IntValue:  &actualUsedBytes,
		},
		remappedmetric.Metric{
			DataType:  pmetric.MetricTypeSum,
			Name:      "system.memory.actual.free",
			Timestamp: timestamp,
			IntValue:  &actualFree,
		},
		remappedmetric.Metric{
			DataType:    pmetric.MetricTypeGauge,
			Name:        "system.memory.used.pct",
			Timestamp:   timestamp,
			DoubleValue: &usedPercent,
		},
		remappedmetric.Metric{
			DataType:    pmetric.MetricTypeGauge,
			Name:        "system.memory.actual.used.pct",
			Timestamp:   timestamp,
			DoubleValue: &actualUsedPercent,
		},
	)

	return nil
}