// Compile amber templates out of assetfs
func MustCompile(filename string) *template.Template {
amberTmpl, err := Asset(filename)
if err != nil {
panic(err)
}
return amber.MustCompile(string(amberTmpl), amber.Options{})
}
func main() {
rand.Seed(time.Now().Unix())
flag.Parse()
// This is only used when we're running in -dev mode with bindata
rootDir, _ = osext.ExecutableFolder()
rootDir = path.Join(rootDir, "web")
// Parse configuration
cfg, err := config.LoadFromFile(*configFile)
if err != nil {
log.Fatalln("Error loading config", err)
}
// Templates
amberTmpl, err := Asset("templates/index.amber")
if err != nil {
log.Fatalln("Could not load index template:", err)
}
tmpl := amber.MustCompile(string(amberTmpl), amber.Options{})
// Setup the web UI
router := httprouter.New()
router.Handler("GET", *metricsPath, prometheus.Handler()) // Prometheus
// Static asset handling
router.GET("/static/*filepath", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
reqpath := ps.ByName("filepath")
realpath := path.Join("static", reqpath)
b, err := Asset(realpath)
if err != nil {
log.Debugln("Could not find asset: ", err)
return
} else {
w.Write(b)
}
})
var monitoredHosts []*pollers.Host
router.GET("/", func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
data := struct {
Cfg *config.Config
Hosts *[]*pollers.Host
}{
Cfg: cfg,
Hosts: &monitoredHosts,
}
err := tmpl.Execute(w, &data)
if err != nil {
log.Errorln("Error rendering template", err)
}
})
// Initialize the host pollers
monitoredHosts = make([]*pollers.Host, len(cfg.Hosts))
// We don't allow duplicate hosts, but also don't want to panic just due
// to a typo, so keep track and skip duplicates here.
seenHosts := make(map[string]bool)
realidx := 0
for _, hostCfg := range cfg.Hosts {
log.Debugln("Setting up poller for: ", hostCfg.Hostname)
if *skipPing {
hostCfg.PingDisable = true
}
if _, ok := seenHosts[hostCfg.Hostname]; ok {
log.Warnln("Discarding repeat configuration of same hostname", hostCfg.Hostname)
continue
}
host := pollers.NewHost(hostCfg)
monitoredHosts[realidx] = host
prometheus.MustRegister(host)
seenHosts[hostCfg.Hostname] = true
realidx++
}
// Trim monitoredHosts to the number we actually used
monitoredHosts = monitoredHosts[0:realidx]
// This is the dispatcher. It is responsible for invoking the doPoll method
// of hosts.
connectionLimiter := pollers.NewLimiter(*maxConnections)
hostQueue := make(chan *pollers.Host)
// Start the host dispatcher
go func() {
for host := range hostQueue {
go host.Poll(connectionLimiter, hostQueue)
}
}()
// Do the initial host dispatch
go func() {
for _, host := range monitoredHosts {
log.Debugln("Starting polling for hosts")
hostQueue <- host
}
}()
var handler http.Handler
// If basic auth is requested, enable it for the interface.
if cfg.BasicAuthUsername != "" && cfg.BasicAuthPassword != "" {
basicauth := httpauth.SimpleBasicAuth(cfg.BasicAuthUsername,
cfg.BasicAuthPassword)
handler = basicauth(router)
} else {
handler = router
}
// If TLS certificates are specificed, use TLS
if cfg.TLSCertificatePath != "" && cfg.TLSKeyPath != "" {
log.Infof("Listening on (TLS-enabled) %s", *listenAddress)
err = http.ListenAndServeTLS(*listenAddress,
cfg.TLSCertificatePath, cfg.TLSKeyPath, handler)
} else {
log.Infof("Listening on %s", *listenAddress)
err = http.ListenAndServe(*listenAddress, handler)
}
if err != nil {
log.Fatal(err)
}
}