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// Copyright 2015 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"fmt"
"net/http"
_ "net/http/pprof"
"sort"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/prometheus/common/log"
"github.com/prometheus/common/version"
"github.com/prometheus/node_exporter/collector"
"gopkg.in/alecthomas/kingpin.v2"
)
func init() {
prometheus.MustRegister(version.NewCollector("node_exporter"))
}
func handler(w http.ResponseWriter, r *http.Request) {
filters := r.URL.Query()["collect[]"]
log.Debugln("collect query:", filters)
nc, err := collector.NewNodeCollector(filters...)
if err != nil {
log.Warnln("Couldn't create", err)
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte(fmt.Sprintf("Couldn't create %s", err)))
return
}
registry := prometheus.NewRegistry()
err = registry.Register(nc)
if err != nil {
log.Errorln("Couldn't register collector:", err)
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(fmt.Sprintf("Couldn't register collector: %s", err)))
return
}
gatherers := prometheus.Gatherers{
prometheus.DefaultGatherer,
registry,
}
// Delegate http serving to Prometheus client library, which will call collector.Collect.
h := promhttp.InstrumentMetricHandler(
registry,
promhttp.HandlerFor(gatherers,
promhttp.HandlerOpts{
ErrorLog: log.NewErrorLogger(),
ErrorHandling: promhttp.ContinueOnError,
}),
)
h.ServeHTTP(w, r)
}
func main() {
var (
listenAddress = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9100").String()
metricsPath = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
)
log.AddFlags(kingpin.CommandLine)
kingpin.Version(version.Print("node_exporter"))
kingpin.HelpFlag.Short('h')
kingpin.Parse()
log.Infoln("Starting node_exporter", version.Info())
log.Infoln("Build context", version.BuildContext())
// This instance is only used to check collector creation and logging.
nc, err := collector.NewNodeCollector()
if err != nil {
log.Fatalf("Couldn't create collector: %s", err)
}
log.Infof("Enabled collectors:")
collectors := []string{}
for n := range nc.Collectors {
collectors = append(collectors, n)
}
sort.Strings(collectors)
for _, n := range collectors {
log.Infof(" - %s", n)
}
http.HandleFunc(*metricsPath, handler)
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(`<html>
<head><title>Node Exporter</title></head>
<body>
<h1>Node Exporter</h1>
<p><a href="` + *metricsPath + `">Metrics</a></p>
</body>
</html>`))
})
log.Infoln("Listening on", *listenAddress)
err = http.ListenAndServe(*listenAddress, nil)
if err != nil {
log.Fatal(err)
}
}
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