telegraf/plugins/inputs/prometheus/parser.go

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2016-03-01 16:12:23 +00:00
package prometheus
// Parser inspired from
// https://github.com/prometheus/prom2json/blob/master/main.go
import (
"bufio"
"bytes"
"fmt"
"io"
"math"
"mime"
"github.com/influxdata/telegraf"
"github.com/matttproud/golang_protobuf_extensions/pbutil"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/common/expfmt"
)
// PrometheusParser is an object for Parsing incoming metrics.
type PrometheusParser struct {
// PromFormat
PromFormat map[string]string
// DefaultTags will be added to every parsed metric
// DefaultTags map[string]string
}
// Parse returns a slice of Metrics from a text representation of a
// metrics
func (p *PrometheusParser) Parse(buf []byte) ([]telegraf.Metric, error) {
var metrics []telegraf.Metric
var parser expfmt.TextParser
// parse even if the buffer begins with a newline
buf = bytes.TrimPrefix(buf, []byte("\n"))
// Read raw data
buffer := bytes.NewBuffer(buf)
reader := bufio.NewReader(buffer)
// Get format
mediatype, params, err := mime.ParseMediaType(p.PromFormat["Content-Type"])
// Prepare output
metricFamilies := make(map[string]*dto.MetricFamily)
if err == nil && mediatype == "application/vnd.google.protobuf" &&
params["encoding"] == "delimited" &&
params["proto"] == "io.prometheus.client.MetricFamily" {
for {
metricFamily := &dto.MetricFamily{}
if _, err = pbutil.ReadDelimited(reader, metricFamily); err != nil {
if err == io.EOF {
break
}
return nil, fmt.Errorf("reading metric family protocol buffer failed: %s", err)
}
metricFamilies[metricFamily.GetName()] = metricFamily
}
} else {
metricFamilies, err = parser.TextToMetricFamilies(reader)
if err != nil {
return nil, fmt.Errorf("reading text format failed: %s", err)
}
// read metrics
for metricName, mf := range metricFamilies {
for _, m := range mf.Metric {
// reading tags
tags := makeLabels(m)
/*
for key, value := range p.DefaultTags {
tags[key] = value
}
*/
// reading fields
fields := make(map[string]interface{})
if mf.GetType() == dto.MetricType_SUMMARY {
// summary metric
fields = makeQuantiles(m)
fields["count"] = float64(m.GetHistogram().GetSampleCount())
fields["sum"] = float64(m.GetSummary().GetSampleSum())
} else if mf.GetType() == dto.MetricType_HISTOGRAM {
// historgram metric
fields = makeBuckets(m)
fields["count"] = float64(m.GetHistogram().GetSampleCount())
fields["sum"] = float64(m.GetSummary().GetSampleSum())
} else {
// standard metric
fields = getNameAndValue(m)
}
// converting to telegraf metric
if len(fields) > 0 {
metric, err := telegraf.NewMetric(metricName, tags, fields)
if err == nil {
metrics = append(metrics, metric)
}
}
}
}
}
return metrics, err
}
// Parse one line
func (p *PrometheusParser) ParseLine(line string) (telegraf.Metric, error) {
metrics, err := p.Parse([]byte(line + "\n"))
if err != nil {
return nil, err
}
if len(metrics) < 1 {
return nil, fmt.Errorf(
"Can not parse the line: %s, for data format: prometheus", line)
}
return metrics[0], nil
}
/*
// Set default tags
func (p *PrometheusParser) SetDefaultTags(tags map[string]string) {
p.DefaultTags = tags
}
*/
// Get Quantiles from summary metric
func makeQuantiles(m *dto.Metric) map[string]interface{} {
fields := make(map[string]interface{})
for _, q := range m.GetSummary().Quantile {
if !math.IsNaN(q.GetValue()) {
fields[fmt.Sprint(q.GetQuantile())] = float64(q.GetValue())
}
}
return fields
}
// Get Buckets from histogram metric
func makeBuckets(m *dto.Metric) map[string]interface{} {
fields := make(map[string]interface{})
for _, b := range m.GetHistogram().Bucket {
fields[fmt.Sprint(b.GetUpperBound())] = float64(b.GetCumulativeCount())
}
return fields
}
// Get labels from metric
func makeLabels(m *dto.Metric) map[string]string {
result := map[string]string{}
for _, lp := range m.Label {
result[lp.GetName()] = lp.GetValue()
}
return result
}
// Get name and value from metric
func getNameAndValue(m *dto.Metric) map[string]interface{} {
fields := make(map[string]interface{})
if m.Gauge != nil {
if !math.IsNaN(m.GetGauge().GetValue()) {
fields["gauge"] = float64(m.GetGauge().GetValue())
}
} else if m.Counter != nil {
if !math.IsNaN(m.GetGauge().GetValue()) {
fields["counter"] = float64(m.GetCounter().GetValue())
}
} else if m.Untyped != nil {
if !math.IsNaN(m.GetGauge().GetValue()) {
fields["value"] = float64(m.GetUntyped().GetValue())
}
}
return fields
}