Adding upstream version 1.34.4.

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

plugins/serializers/prometheus/prometheus.go

@@ -0,0 +1,95 @@
+package prometheus
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/prometheus/common/expfmt"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/filter"
+	"github.com/influxdata/telegraf/plugins/serializers"
+)
+
+type MetricTypes struct {
+	Counter []string `toml:"counter"`
+	Gauge   []string `toml:"gauge"`
+
+	filterCounter filter.Filter
+	filterGauge   filter.Filter
+}
+
+func (mt *MetricTypes) Init() error {
+	// Setup the explicit type mappings
+	var err error
+	mt.filterCounter, err = filter.Compile(mt.Counter)
+	if err != nil {
+		return fmt.Errorf("creating counter filter failed: %w", err)
+	}
+	mt.filterGauge, err = filter.Compile(mt.Gauge)
+	if err != nil {
+		return fmt.Errorf("creating gauge filter failed: %w", err)
+	}
+	return nil
+}
+
+func (mt *MetricTypes) DetermineType(name string, m telegraf.Metric) telegraf.ValueType {
+	metricType := m.Type()
+	if mt.filterCounter != nil && mt.filterCounter.Match(name) {
+		metricType = telegraf.Counter
+	}
+	if mt.filterGauge != nil && mt.filterGauge.Match(name) {
+		metricType = telegraf.Gauge
+	}
+	return metricType
+}
+
+type FormatConfig struct {
+	ExportTimestamp bool `toml:"prometheus_export_timestamp"`
+	SortMetrics     bool `toml:"prometheus_sort_metrics"`
+	StringAsLabel   bool `toml:"prometheus_string_as_label"`
+	// CompactEncoding defines whether to include
+	// HELP metadata in Prometheus payload. Setting to true
+	// helps to reduce payload size.
+	CompactEncoding bool        `toml:"prometheus_compact_encoding"`
+	TypeMappings    MetricTypes `toml:"prometheus_metric_types"`
+}
+
+type Serializer struct {
+	FormatConfig
+}
+
+func (s *Serializer) Init() error {
+	return s.FormatConfig.TypeMappings.Init()
+}
+
+func (s *Serializer) Serialize(metric telegraf.Metric) ([]byte, error) {
+	return s.SerializeBatch([]telegraf.Metric{metric})
+}
+
+func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
+	coll := NewCollection(s.FormatConfig)
+	for _, metric := range metrics {
+		coll.Add(metric, time.Now())
+	}
+
+	var buf bytes.Buffer
+	for _, mf := range coll.GetProto() {
+		enc := expfmt.NewEncoder(&buf, expfmt.NewFormat(expfmt.TypeTextPlain))
+		err := enc.Encode(mf)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return buf.Bytes(), nil
+}
+
+func init() {
+	serializers.Add("prometheus",
+		func() telegraf.Serializer {
+			return &Serializer{}
+		},
+	)
+}