package main
import (
"flag"
"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"
)
var (
showVersion = flag.Bool("version", false, "Print version information.")
configFile = flag.String(
"config.file", "ipmi.yml",
"Path to configuration file.",
)
executablesPath = flag.String(
"path", "",
"Path to FreeIPMI executables (default: rely on $PATH).",
)
listenAddress = flag.String(
"web.listen-address", ":9290",
"Address to listen on for web interface and telemetry.",
)
sc = &SafeConfig{
C: &Config{},
}
reloadCh chan chan error
)
func handler(w http.ResponseWriter, r *http.Request) {
target := r.URL.Query().Get("target")
if target == "" {
http.Error(w, "'target' parameter must be specified", 400)
return
}
log.Debugf("Scraping target '%s'", target)
registry := prometheus.NewRegistry()
collector := collector{target: target, config: sc}
registry.MustRegister(collector)
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() {
flag.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
}
}
}
}()
http.Handle("/metrics", promhttp.Handler()) // Normal metrics endpoint for IPMI exporter itself.
http.HandleFunc("/ipmi", handler) // 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
Config
`))
})
log.Infof("Listening on %s", *listenAddress)
err := http.ListenAndServe(*listenAddress, nil)
if err != nil {
log.Fatal(err)
}
}