categraf/inputs/mtail/internal/exporter/varz.go

61 lines
1.4 KiB
Go

// Copyright 2015 Google Inc. All Rights Reserved.
// This file is available under the Apache license.
package exporter
import (
"expvar"
"fmt"
"net/http"
"sort"
"strings"
"flashcat.cloud/categraf/inputs/mtail/internal/metrics"
)
var exportVarzTotal = expvar.NewInt("exporter_varz_total")
const varzFormat = "%s{%s} %s\n"
// HandleVarz exports the metrics in Varz format via HTTP.
func (e *Exporter) HandleVarz(w http.ResponseWriter, r *http.Request) {
w.Header().Add("Content-type", "text/plain")
err := e.store.Range(func(m *metrics.Metric) error {
select {
case <-r.Context().Done():
return r.Context().Err()
default:
}
m.RLock()
exportVarzTotal.Add(1)
lc := make(chan *metrics.LabelSet)
go m.EmitLabelSets(lc)
for l := range lc {
line := metricToVarz(m, l, e.omitProgLabel, e.hostname)
fmt.Fprint(w, line)
}
m.RUnlock()
return nil
})
if err != nil {
http.Error(w, fmt.Sprintf("%s", err), http.StatusInternalServerError)
}
}
func metricToVarz(m *metrics.Metric, l *metrics.LabelSet, omitProgLabel bool, hostname string) string {
s := make([]string, 0, len(l.Labels)+2)
for k, v := range l.Labels {
s = append(s, fmt.Sprintf("%s=%s", k, v))
}
sort.Strings(s)
if !omitProgLabel {
s = append(s, fmt.Sprintf("prog=%s", m.Program))
}
s = append(s, fmt.Sprintf("instance=%s", hostname))
return fmt.Sprintf(varzFormat,
m.Name,
strings.Join(s, ","),
l.Datum.ValueString())
}