// sanitizeLabels ensures that all the labels in groupingLabels and the
// `instance` label are present in each MetricFamily in metricFamilies. The
// label values from groupingLabels are set in each MetricFamily, no matter
// what. After that, if the 'instance' label is not present at all in a
// MetricFamily, it will be created (with an empty string as value).
//
// Finally, sanitizeLabels sorts the label pairs of all metrics.
func sanitizeLabels(
metricFamilies map[string]*dto.MetricFamily,
groupingLabels map[string]string,
) {
gLabelsNotYetDone := make(map[string]string, len(groupingLabels))
for _, mf := range metricFamilies {
metric:
for _, m := range mf.GetMetric() {
for ln, lv := range groupingLabels {
gLabelsNotYetDone[ln] = lv
}
hasInstanceLabel := false
for _, lp := range m.GetLabel() {
ln := lp.GetName()
if lv, ok := gLabelsNotYetDone[ln]; ok {
lp.Value = proto.String(lv)
delete(gLabelsNotYetDone, ln)
}
if ln == string(model.InstanceLabel) {
hasInstanceLabel = true
}
if len(gLabelsNotYetDone) == 0 && hasInstanceLabel {
sort.Sort(prometheus.LabelPairSorter(m.Label))
continue metric
}
}
for ln, lv := range gLabelsNotYetDone {
m.Label = append(m.Label, &dto.LabelPair{
Name: proto.String(ln),
Value: proto.String(lv),
})
if ln == string(model.InstanceLabel) {
hasInstanceLabel = true
}
delete(gLabelsNotYetDone, ln) // To prepare map for next metric.
}
if !hasInstanceLabel {
m.Label = append(m.Label, &dto.LabelPair{
Name: proto.String(string(model.InstanceLabel)),
Value: proto.String(""),
})
}
sort.Sort(prometheus.LabelPairSorter(m.Label))
}
}
}
// sanitizeLabels ensures that all the labels in groupingLabels and
// requiredLabels are present in each MetricFamily in metricFamilies. The label
// values from groupingLabels are set in each MetricFamily, no matter what. In
// contrast, requiredLabels contains only label names and no label values. Only
// if any of those labels are not present at all in a MetricFamily, they will be
// created (with an empty string as value).
//
// Finally, sanitizeLabels sorts the label pairs of all metrics.
func sanitizeLabels(
metricFamilies map[string]*dto.MetricFamily,
groupingLabels map[string]string, requiredLabels map[string]struct{},
) {
gLabelsNotYetDone := make(map[string]string, len(groupingLabels))
rLabelsNotYetDone := make(map[string]struct{}, len(requiredLabels))
for _, mf := range metricFamilies {
metric:
for _, m := range mf.GetMetric() {
for ln, lv := range groupingLabels {
gLabelsNotYetDone[ln] = lv
}
for ln := range requiredLabels {
rLabelsNotYetDone[ln] = struct{}{}
}
for _, lp := range m.GetLabel() {
ln := lp.GetName()
delete(rLabelsNotYetDone, ln)
if lv, ok := gLabelsNotYetDone[ln]; ok {
lp.Value = proto.String(lv)
delete(gLabelsNotYetDone, ln)
}
if len(gLabelsNotYetDone)+len(rLabelsNotYetDone) == 0 {
sort.Sort(prometheus.LabelPairSorter(m.Label))
continue metric
}
}
for ln, lv := range gLabelsNotYetDone {
m.Label = append(m.Label, &dto.LabelPair{
Name: proto.String(ln),
Value: proto.String(lv),
})
delete(rLabelsNotYetDone, ln)
delete(gLabelsNotYetDone, ln) // To prepare map for next metric.
}
for ln := range rLabelsNotYetDone {
m.Label = append(m.Label, &dto.LabelPair{
Name: proto.String(ln),
Value: proto.String(""),
})
delete(rLabelsNotYetDone, ln) // To prepare map for next metric.
}
sort.Sort(prometheus.LabelPairSorter(m.Label))
}
}
}
func ExampleLabelPairSorter() {
labelPairs := []*dto.LabelPair{
&dto.LabelPair{Name: proto.String("status"), Value: proto.String("404")},
&dto.LabelPair{Name: proto.String("method"), Value: proto.String("get")},
}
sort.Sort(prometheus.LabelPairSorter(labelPairs))
fmt.Println(labelPairs)
// Output:
// [name:"method" value:"get" name:"status" value:"404" ]
}