func main() {
flag.Parse()
if *cfgAddr == "" {
fmt.Println("required flag not provided: --config-http-address")
os.Exit(1)
}
if *dnsAddr == "" {
fmt.Println("required flag not provided: --lookupd-dns-address")
os.Exit(1)
}
log.SetHandler(text.New(os.Stderr))
ctx := log.WithFields(log.Fields{
"cfgAddr": *cfgAddr,
"dnsAddr": *dnsAddr,
"ldPort": *ldPort,
})
ips, err := dnscfg.Get(dnsAddr, ldPort)
if err != nil {
ctx.WithError(err).Error("dns lookup")
os.Exit(1)
}
if len(ips) == 0 {
ctx.Error("no ip addresses found")
os.Exit(1)
}
cfgURL := "http://" + *cfgAddr + "/config/nsqlookupd_tcp_addresses"
err = httpcfg.Set(cfgURL, ips)
if err != nil {
ctx.WithError(err).Error("setting config")
} else {
ctx.WithField("ips", ips).Info("setting config")
}
go configLoop(ctx, cfgURL)
http.ListenAndServe(":6060", nil)
}
// continue looking at dns entry for changes in config
func configLoop(ctx log.Interface, cfgURL string) {
ticker := time.Tick(15 * time.Second)
for {
select {
case <-ticker:
newIPs, err := dnscfg.Get(dnsAddr, ldPort)
if err != nil {
ctx.WithError(err).Error("dns lookup")
continue
}
if len(newIPs) == 0 {
ctx.Error("no ip addresses found")
continue
}
oldIPs, err := httpcfg.Get(cfgURL)
if err != nil {
ctx.WithError(err).Error("getting config")
continue
}
if eq(newIPs, oldIPs) {
ctx.Info("config up to date")
continue
}
err = httpcfg.Set(cfgURL, newIPs)
if err != nil {
ctx.WithError(err).Error("setting config")
continue
}
ctx.WithField("ips", newIPs).Info("setting config")
}
}
}