func detectMasters(zk string, masters []string) <-chan []string {
changed := make(chan []string, 1)
if zk != "" {
logging.Verbose.Println("Starting master detector for ZK ", zk)
if md, err := detector.New(zk); err != nil {
log.Fatalf("failed to create master detector: %v", err)
} else if err := md.Detect(detect.NewMasters(masters, changed)); err != nil {
log.Fatalf("failed to initialize master detector: %v", err)
}
} else {
changed <- masters
}
return changed
}
func main() {
util.PanicHandlers = append(util.PanicHandlers, func(_ interface{}) {
// by default the handler already logs the panic
os.Exit(1)
})
var versionFlag bool
// parse flags
cjson := flag.String("config", "config.json", "path to config file (json)")
flag.BoolVar(&versionFlag, "version", false, "output the version")
flag.Parse()
// -version
if versionFlag {
fmt.Println(version)
os.Exit(0)
}
// initialize logging
logging.SetupLogs()
// initialize resolver
config := records.SetConfig(*cjson)
res := resolver.New(version, config)
errch := make(chan error)
// launch DNS server
if config.DNSOn {
go func() { errch <- <-res.LaunchDNS() }()
}
// launch HTTP server
if config.HTTPOn {
go func() { errch <- <-res.LaunchHTTP() }()
}
changed := make(chan []string, 1)
if config.Zk != "" {
logging.Verbose.Println("Starting master detector for ZK ", config.Zk)
if md, err := detector.New(config.Zk); err != nil {
log.Fatalf("failed to create master detector: %v", err)
} else if err := md.Detect(detect.NewMasters(config.Masters, changed)); err != nil {
log.Fatalf("failed to initialize master detector: %v", err)
}
} else {
changed <- config.Masters
}
reload := time.NewTicker(time.Second * time.Duration(config.RefreshSeconds))
timeout := time.AfterFunc(zkInitialDetectionTimeout, func() {
errch <- fmt.Errorf("master detection timed out after %s", zkInitialDetectionTimeout)
})
defer reload.Stop()
defer util.HandleCrash()
for {
select {
case <-reload.C:
res.Reload()
case masters := <-changed:
timeout.Stop()
logging.VeryVerbose.Printf("new masters detected: %v", masters)
res.SetMasters(masters)
res.Reload()
case err := <-errch:
logging.Error.Fatal(err)
}
}
}