Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

metric/series_grouper.go

@@ -0,0 +1,106 @@
+package metric
+
+import (
+	"encoding/binary"
+	"hash/maphash"
+	"sort"
+	"time"
+
+	"github.com/influxdata/telegraf"
+)
+
+// NewSeriesGrouper returns a type that can be used to group fields by series
+// and time, so that fields which share these values will be combined into a
+// single telegraf.Metric.
+//
+// This is useful to build telegraf.Metric's when all fields for a series are
+// not available at once.
+//
+// ex:
+// - cpu,host=localhost usage_time=42
+// - cpu,host=localhost idle_time=42
+// + cpu,host=localhost idle_time=42,usage_time=42
+func NewSeriesGrouper() *SeriesGrouper {
+	return &SeriesGrouper{
+		metrics:  make(map[uint64]telegraf.Metric),
+		ordered:  make([]telegraf.Metric, 0),
+		hashSeed: maphash.MakeSeed(),
+	}
+}
+
+type SeriesGrouper struct {
+	metrics map[uint64]telegraf.Metric
+	ordered []telegraf.Metric
+
+	hashSeed maphash.Seed
+}
+
+// Add adds a field key and value to the series.
+func (g *SeriesGrouper) Add(
+	measurement string,
+	tags map[string]string,
+	tm time.Time,
+	field string,
+	fieldValue interface{},
+) {
+	taglist := make([]*telegraf.Tag, 0, len(tags))
+	for k, v := range tags {
+		taglist = append(taglist,
+			&telegraf.Tag{Key: k, Value: v})
+	}
+	sort.Slice(taglist, func(i, j int) bool { return taglist[i].Key < taglist[j].Key })
+
+	id := groupID(g.hashSeed, measurement, taglist, tm)
+	m := g.metrics[id]
+	if m == nil {
+		m = New(measurement, tags, map[string]interface{}{field: fieldValue}, tm)
+		g.metrics[id] = m
+		g.ordered = append(g.ordered, m)
+	} else {
+		m.AddField(field, fieldValue)
+	}
+}
+
+// AddMetric adds a metric to the series, merging with any previous matching metrics.
+func (g *SeriesGrouper) AddMetric(
+	metric telegraf.Metric,
+) {
+	id := groupID(g.hashSeed, metric.Name(), metric.TagList(), metric.Time())
+	m := g.metrics[id]
+	if m == nil {
+		m = metric.Copy()
+		g.metrics[id] = m
+		g.ordered = append(g.ordered, m)
+	} else {
+		for _, f := range metric.FieldList() {
+			m.AddField(f.Key, f.Value)
+		}
+	}
+}
+
+// Metrics returns the metrics grouped by series and time.
+func (g *SeriesGrouper) Metrics() []telegraf.Metric {
+	return g.ordered
+}
+
+func groupID(seed maphash.Seed, measurement string, taglist []*telegraf.Tag, tm time.Time) uint64 {
+	var mh maphash.Hash
+	mh.SetSeed(seed)
+
+	mh.WriteString(measurement)
+	mh.WriteByte(0)
+
+	for _, tag := range taglist {
+		mh.WriteString(tag.Key)
+		mh.WriteByte(0)
+		mh.WriteString(tag.Value)
+		mh.WriteByte(0)
+	}
+	mh.WriteByte(0)
+
+	var tsBuf [8]byte
+	binary.BigEndian.PutUint64(tsBuf[:], uint64(tm.UnixNano()))
+	mh.Write(tsBuf[:])
+
+	return mh.Sum64()
+}