Function groupingKeyFor

storage/diskmetricstore.go:462–483

groupingKeyFor creates a grouping key from the provided map of grouping labels. The grouping key is created by joining all label names and values together with model.SeparatorByte as a separator. The label names are sorted lexicographically before joining. In that way, the grouping key is both repro

(labels map[string]string)

// lexicographically before joining. In that way, the grouping key is both
// reproducible and unique.
func groupingKeyFor(labels map[string]string) string {
	if len(labels) == 0 { // Super fast path.
		return ""
	}

	labelNames := make([]string, 0, len(labels))
	for labelName := range labels {
		labelNames = append(labelNames, labelName)
	}
	sort.Strings(labelNames)

	sb := strings.Builder{}
	for i, labelName := range labelNames {
		sb.WriteString(labelName)
		sb.WriteByte(model.SeparatorByte)
		sb.WriteString(labels[labelName])
		if i+1 < len(labels) { // No separator at the end.
			sb.WriteByte(model.SeparatorByte)
		}
	}
	return sb.String()
}

// extractPredefinedHelpStrings extracts all the HELP strings from the provided
// gatherer so that the DiskMetricStore can fix deviations in pushed metrics.