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)
}
}
}
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)
}
}
}
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)
}
}
}