traefik/vendor/github.com/mesosphere/mesos-dns/main.go
2017-03-09 13:13:02 +01:00

98 lines
2.3 KiB
Go

package main
import (
"flag"
"fmt"
"log"
"os"
"time"
"github.com/mesos/mesos-go/detector"
"github.com/mesosphere/mesos-dns/detect"
"github.com/mesosphere/mesos-dns/logging"
"github.com/mesosphere/mesos-dns/records"
"github.com/mesosphere/mesos-dns/resolver"
"github.com/mesosphere/mesos-dns/util"
)
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 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
}