// Copyright 2021 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"
"os"
"os/signal"
"syscall"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/prometheus/common/log"
"github.com/prometheus/common/version"
kingpin "gopkg.in/alecthomas/kingpin.v2"
)
var (
configFile = kingpin.Flag(
"config.file",
"Path to configuration file.",
).String()
executablesPath = kingpin.Flag(
"freeipmi.path",
"Path to FreeIPMI executables (default: rely on $PATH).",
).String()
listenAddress = kingpin.Flag(
"web.listen-address",
"Address to listen on for web interface and telemetry.",
).Default(":9290").String()
sc = &SafeConfig{
C: &Config{},
}
reloadCh chan chan error
)
func remoteIPMIHandler(w http.ResponseWriter, r *http.Request) {
target := r.URL.Query().Get("target")
if target == "" {
http.Error(w, "'target' parameter must be specified", 400)
return
}
// Remote scrape will not work without some kind of config, so be pedantic about it
module := r.URL.Query().Get("module")
if module == "" {
module = "default"
}
if !sc.HasModule(module) {
http.Error(w, fmt.Sprintf("Unknown module %q", module), http.StatusBadRequest)
return
}
log.Debugf("Scraping target '%s' with module '%s'", target, module)
registry := prometheus.NewRegistry()
remoteCollector := metaCollector{target: target, module: module, config: sc}
registry.MustRegister(remoteCollector)
h := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
h.ServeHTTP(w, r)
}
func updateConfiguration(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case "POST":
rc := make(chan error)
reloadCh <- rc
if err := <-rc; err != nil {
http.Error(w, fmt.Sprintf("failed to reload config: %s", err), http.StatusInternalServerError)
}
default:
log.Errorf("Only POST requests allowed for %s", r.URL)
w.Header().Set("Allow", "POST")
http.Error(w, "Only POST requests allowed", http.StatusMethodNotAllowed)
}
}
func main() {
log.AddFlags(kingpin.CommandLine)
kingpin.HelpFlag.Short('h')
kingpin.Version(version.Print("ipmi_exporter"))
kingpin.Parse()
log.Infoln("Starting ipmi_exporter")
// Bail early if the config is bad.
if err := sc.ReloadConfig(*configFile); err != nil {
log.Fatalf("Error parsing config file: %s", err)
}
hup := make(chan os.Signal)
reloadCh = make(chan chan error)
signal.Notify(hup, syscall.SIGHUP)
go func() {
for {
select {
case <-hup:
if err := sc.ReloadConfig(*configFile); err != nil {
log.Errorf("Error reloading config: %s", err)
}
case rc := <-reloadCh:
if err := sc.ReloadConfig(*configFile); err != nil {
log.Errorf("Error reloading config: %s", err)
rc <- err
} else {
rc <- nil
}
}
}
}()
localCollector := metaCollector{target: targetLocal, module: "default", config: sc}
prometheus.MustRegister(&localCollector)
http.Handle("/metrics", promhttp.Handler()) // Regular metrics endpoint for local IPMI metrics.
http.HandleFunc("/ipmi", remoteIPMIHandler) // Endpoint to do IPMI scrapes.
http.HandleFunc("/-/reload", updateConfiguration) // Endpoint to reload configuration.
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(`
IPMI Exporter
IPMI Exporter
Local metrics
Config
`))
})
log.Infof("Listening on %s", *listenAddress)
err := http.ListenAndServe(*listenAddress, nil)
if err != nil {
log.Fatal(err)
}
}