Пример #1
0
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)
		}
	}
}
Пример #2
0
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 := detectMasters(config.Zk, config.Masters)
	reload := time.NewTicker(time.Second * time.Duration(config.RefreshSeconds))
	zkTimeout := time.Second * time.Duration(config.ZkDetectionTimeout)
	timeout := time.AfterFunc(zkTimeout, func() {
		if zkTimeout > 0 {
			errch <- fmt.Errorf("master detection timed out after %s", zkTimeout)
		}
	})

	defer reload.Stop()
	defer util.HandleCrash()
	for {
		select {
		case <-reload.C:
			res.Reload()
		case masters := <-changed:
			if len(masters) == 0 || masters[0] == "" { // no leader
				timeout.Reset(zkTimeout)
			} else {
				timeout.Stop()
			}
			logging.VeryVerbose.Printf("new masters detected: %v", masters)
			res.SetMasters(masters)
			res.Reload()
		case err := <-errch:
			logging.Error.Fatal(err)
		}
	}
}
Пример #3
0
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)
	resolver := resolver.New(version, config)

	var dnsErr, httpErr, zkErr <-chan error
	var newLeader <-chan struct{}

	// launch DNS server
	if config.DNSOn {
		dnsErr = resolver.LaunchDNS()
	}

	// launch HTTP server
	if config.HTTPOn {
		httpErr = resolver.LaunchHTTP()
	}

	// launch Zookeeper listener
	if config.Zk != "" {
		newLeader, zkErr = resolver.LaunchZK(zkInitialDetectionTimeout)
	} else {
		// uniform behavior when new leader from masters field
		leader := make(chan struct{}, 1)
		leader <- struct{}{}
		newLeader = leader
	}

	// print error and terminate
	handleServerErr := func(name string, err error) {
		if err != nil {
			logging.Error.Fatalf("%s failed: %v", name, err)
		} else {
			logging.Error.Fatalf("%s stopped unexpectedly", name)
		}
	}

	// generate reload signal; up to 1 reload pending at any time
	reloadSignal := make(chan struct{}, 1)
	tryReload := func() {
		// non-blocking, attempt to queue a reload
		select {
		case reloadSignal <- struct{}{}:
		default:
		}
	}

	// periodic loading of DNS state (pull from Master)
	go func() {
		defer util.HandleCrash()
		reloadTimeout := time.Second * time.Duration(config.RefreshSeconds)
		reloadTimer := time.AfterFunc(reloadTimeout, tryReload)
		for _ = range reloadSignal {
			resolver.Reload()
			logging.PrintCurLog()
			reloadTimer.Reset(reloadTimeout)
		}
	}()

	// infinite loop until there is fatal error
	for {
		select {
		case <-newLeader:
			tryReload()
		case err := <-dnsErr:
			handleServerErr("DNS server", err)
		case err := <-httpErr:
			handleServerErr("HTTP server", err)
		case err := <-zkErr:
			handleServerErr("ZK watcher", err)
		}
	}
}