1 files changed, 110 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/pkg/prometheus/metric_series.go b/src/go/collectors/go.d.plugin/pkg/prometheus/metric_series.go
new file mode 100644
index 000000000..31914f4b2
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/pkg/prometheus/metric_series.go
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package prometheus
+
+import (
+	"sort"
+
+	"github.com/prometheus/prometheus/model/labels"
+)
+
+type (
+	// SeriesSample is a pair of label set and value
+	SeriesSample struct {
+		Labels labels.Labels
+		Value  float64
+	}
+
+	// Series is a list of SeriesSample
+	Series []SeriesSample
+)
+
+// Name the __name__ label value
+func (s SeriesSample) Name() string {
+	return s.Labels[0].Value
+}
+
+// Add appends a metric.
+func (s *Series) Add(kv SeriesSample) {
+	*s = append(*s, kv)
+}
+
+// Reset resets the buffer to be empty,
+// but it retains the underlying storage for use by future writes.
+func (s *Series) Reset() {
+	*s = (*s)[:0]
+}
+
+// Sort sorts data.
+func (s Series) Sort() {
+	sort.Sort(s)
+}
+
+// Len returns metric length.
+func (s Series) Len() int {
+	return len(s)
+}
+
+// Less reports whether the element with
+// index i should sort before the element with index j.
+func (s Series) Less(i, j int) bool {
+	return s[i].Name() < s[j].Name()
+}
+
+// Swap swaps the elements with indexes i and j.
+func (s Series) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+// FindByName finds metrics where it's __name__ label matches given name.
+// It expects the metrics is sorted.
+// Complexity: O(log(N))
+func (s Series) FindByName(name string) Series {
+	from := sort.Search(len(s), func(i int) bool {
+		return s[i].Name() >= name
+	})
+	if from == len(s) || s[from].Name() != name { // not found
+		return Series{}
+	}
+	until := from + 1
+	for until < len(s) && s[until].Name() == name {
+		until++
+	}
+	return s[from:until]
+}
+
+// FindByNames finds metrics where it's __name__ label matches given any of names.
+// It expects the metrics is sorted.
+// Complexity: O(log(N))
+func (s Series) FindByNames(names ...string) Series {
+	switch len(names) {
+	case 0:
+		return Series{}
+	case 1:
+		return s.FindByName(names[0])
+	}
+	var result Series
+	for _, name := range names {
+		result = append(result, s.FindByName(name)...)
+	}
+	return result
+}
+
+// Max returns the max value.
+// It does NOT expect the metrics is sorted.
+// Complexity: O(N)
+func (s Series) Max() float64 {
+	switch len(s) {
+	case 0:
+		return 0
+	case 1:
+		return s[0].Value
+	}
+	max := s[0].Value
+	for _, kv := range s[1:] {
+		if max < kv.Value {
+			max = kv.Value
+		}
+	}
+	return max
+}