libvirtd_exporter.go

// Copyright 2019 VEXXHOST, Inc.
//
// 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 (
	"log"
	"net/http"
	"os"

	"github.com/alecthomas/kingpin/v2"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/prometheus/common/promslog"
	"github.com/prometheus/common/promslog/flag"
	"github.com/prometheus/common/version"
	"github.com/prometheus/exporter-toolkit/web"
	webflag "github.com/prometheus/exporter-toolkit/web/kingpinflag"
	"libvirt.org/go/libvirt"

	"github.com/vexxhost/libvirtd_exporter/collectors"
)

var (
	metricsPath = kingpin.Flag(
		"web.telemetry-path",
		"Path under which to expose metrics.",
	).Default("/metrics").String()
	toolkitFlags = webflag.AddFlags(kingpin.CommandLine, ":9474")
	libvirtURI   = kingpin.Flag(
		"libvirt.uri",
		"Libvirt Connection URI",
	).Default("qemu:///system").String()
	libvirtNova = kingpin.Flag(
		"libvirt.nova",
		"Parse Libvirt Nova metadata",
	).Bool()
)

func main() {
	promlogConfig := &promslog.Config{}
	flag.AddFlags(kingpin.CommandLine, promlogConfig)

	kingpin.Version(version.Print("libvirtd_exporter"))
	kingpin.HelpFlag.Short('h')
	kingpin.Parse()

	logger := promslog.New(promlogConfig)

	logger.With("version", version.Info()).Info("Starting libvirtd_exporter")
	logger.With("build_context", version.BuildContext()).Info("Build context")

	conn, err := libvirt.NewConnect(*libvirtURI)
	if err != nil {
		log.Fatalln(err)
		return
	}

	reg := prometheus.NewRegistry()
	reg.MustRegister(
		collectors.NewVersionCollector(logger, conn),
		collectors.NewDomainStatsCollector(logger, conn, *libvirtNova),
	)

	http.Handle(*metricsPath, promhttp.HandlerFor(reg, promhttp.HandlerOpts{Registry: reg}))
	if *metricsPath != "/" && *metricsPath != "" {
		landingConfig := web.LandingConfig{
			Name:        "LibvirtD Exporter",
			Description: "Prometheus Exporter for LibvirtD",
			Version:     version.Info(),
			Links: []web.LandingLinks{
				{
					Address: *metricsPath,
					Text:    "Metrics",
				},
			},
		}
		landingPage, err := web.NewLandingPage(landingConfig)
		if err != nil {
			logger.Error("Error creating landing page", "err", err)
			os.Exit(1)
		}
		http.Handle("/", landingPage)
	}

	srv := &http.Server{}
	if err := web.ListenAndServe(srv, toolkitFlags, logger); err != nil {
		logger.Error("Error starting HTTP server", "err", err)
		os.Exit(1)
	}
}