Adding upstream version 1.34.4.

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

plugins/parsers/prometheus/parser.go

@@ -0,0 +1,99 @@
+package prometheus
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+
+	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/parsers"
+)
+
+func AcceptsContent(header http.Header) bool {
+	return expfmt.ResponseFormat(header).FormatType() != expfmt.TypeUnknown
+}
+
+type Parser struct {
+	IgnoreTimestamp bool              `toml:"prometheus_ignore_timestamp"`
+	MetricVersion   int               `toml:"prometheus_metric_version"`
+	Header          http.Header       `toml:"-"` // set by the prometheus input
+	DefaultTags     map[string]string `toml:"-"`
+	Log             telegraf.Logger   `toml:"-"`
+}
+
+func (p *Parser) SetDefaultTags(tags map[string]string) {
+	p.DefaultTags = tags
+}
+
+func (p *Parser) Parse(data []byte) ([]telegraf.Metric, error) {
+	// Determine the metric transport-type derived from the response header and
+	// create a matching decoder.
+	format := expfmt.NewFormat(expfmt.TypeProtoCompact)
+	if len(p.Header) > 0 {
+		format = expfmt.ResponseFormat(p.Header)
+		switch format.FormatType() {
+		case expfmt.TypeProtoText:
+			// Make sure we have a finishing newline but no trailing one
+			data = bytes.TrimPrefix(data, []byte("\n"))
+			if !bytes.HasSuffix(data, []byte("\n")) {
+				data = append(data, []byte("\n")...)
+			}
+		case expfmt.TypeUnknown:
+			p.Log.Debugf("Unknown format %q... Trying to continue...", p.Header.Get("Content-Type"))
+		}
+	}
+	buf := bytes.NewBuffer(data)
+	decoder := expfmt.NewDecoder(buf, format)
+
+	// Decode the input data into prometheus metrics
+	var metrics []telegraf.Metric
+	for {
+		var mf dto.MetricFamily
+		if err := decoder.Decode(&mf); err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return nil, fmt.Errorf("decoding response failed: %w", err)
+		}
+
+		switch p.MetricVersion {
+		case 0, 2:
+			metrics = append(metrics, p.extractMetricsV2(&mf)...)
+		case 1:
+			metrics = append(metrics, p.extractMetricsV1(&mf)...)
+		default:
+			return nil, fmt.Errorf("unknown prometheus metric version %d", p.MetricVersion)
+		}
+	}
+	return metrics, nil
+}
+
+func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
+	metrics, err := p.Parse([]byte(line))
+	if err != nil {
+		return nil, err
+	}
+
+	if len(metrics) < 1 {
+		return nil, errors.New("no metrics in line")
+	}
+
+	if len(metrics) > 1 {
+		return nil, errors.New("more than one metric in line")
+	}
+
+	return metrics[0], nil
+}
+
+func init() {
+	parsers.Add("prometheus",
+		func(string) telegraf.Parser {
+			return &Parser{}
+		},
+	)
+}