/
main.go
172 lines (158 loc) · 4.07 KB
/
main.go
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package main
import (
"flag"
"io/ioutil"
"log"
"net/http"
"os"
"os/exec"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/route53"
"github.com/coreos/go-systemd/daemon"
)
func getExternalIPMethod1() string {
out, err := exec.Command("/usr/bin/dig", "+short", "myip.opendns.com", "@resolver1.opendns.com").Output()
if err != nil {
log.Printf("Error get my external IP Address - Method #1 dig: %s", err)
return ""
}
return strings.TrimSpace(string(out))
}
func getExternalIPMethod2() string {
resp, err := http.Get("http://ipinfo.io/ip")
if err != nil {
log.Printf("Error get my external IP Address - Method #2 ipinfo: %s", err)
return ""
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Printf("Error get my external IP Address - Method #2 ipinfo: %s", err)
return ""
}
return strings.TrimSpace(string(body))
}
func getMyExternalIP() string {
var ip string
ip = getExternalIPMethod1()
if ip != "" {
return ip
}
ip = getExternalIPMethod2()
return ip
}
func setIPinAWS(recordSetName string, ip string, zoneID string) bool {
svc := route53.New(session.New())
input := &route53.ChangeResourceRecordSetsInput{
ChangeBatch: &route53.ChangeBatch{
Changes: []*route53.Change{
{
Action: aws.String("UPSERT"),
ResourceRecordSet: &route53.ResourceRecordSet{
ResourceRecords: []*route53.ResourceRecord{
{
Value: aws.String(ip),
},
},
Name: aws.String(recordSetName),
TTL: aws.Int64(300),
Type: aws.String("A"),
},
},
},
Comment: aws.String("Update of AWSmyIP"),
},
HostedZoneId: aws.String(zoneID),
}
result, err := svc.ChangeResourceRecordSets(input)
if err != nil {
if aerr, ok := err.(awserr.Error); ok {
switch aerr.Code() {
case route53.ErrCodeNoSuchHostedZone:
log.Println(route53.ErrCodeNoSuchHostedZone, aerr.Error())
case route53.ErrCodeNoSuchHealthCheck:
log.Println(route53.ErrCodeNoSuchHealthCheck, aerr.Error())
case route53.ErrCodeInvalidChangeBatch:
log.Println(route53.ErrCodeInvalidChangeBatch, aerr.Error())
case route53.ErrCodeInvalidInput:
log.Println(route53.ErrCodeInvalidInput, aerr.Error())
case route53.ErrCodePriorRequestNotComplete:
log.Println(route53.ErrCodePriorRequestNotComplete, aerr.Error())
default:
log.Println(aerr.Error())
}
} else {
// Print the error, cast err to awserr.Error to get the Code and
// Message from an error.
log.Println(err.Error())
}
return false
}
return *result.ChangeInfo.Status == route53.ChangeStatusPending
}
var zoneID *string
var recordSet *string
var noDaemon *bool
var logFile *string
var lastIP string
const intervalSleep = 15 * time.Minute
func init() {
zoneID = flag.String("zoneID", "", "Zone ID")
recordSet = flag.String("recordSet", "", "Record Set")
noDaemon = flag.Bool("noDaemon", false, "No daemon flag")
logFile = flag.String("logFile", "", "If specified, logging in that path")
}
func main() {
log.Println("AWS Auto-update IP Remote Address")
flag.Parse()
if *logFile != "" {
f, err := os.OpenFile(*logFile, os.O_RDWR | os.O_CREATE | os.O_APPEND, 0666)
if err != nil {
log.Fatalf("error opening file: %v", err)
}
defer f.Close()
log.SetOutput(f)
}
if *zoneID == "" {
log.Fatal("Need specify: zoneID")
return
}
if *recordSet == "" {
log.Fatal("Need specify: recordSet")
return
}
if !(*noDaemon) {
daemon.SdNotify(false, "READY=1")
go func() {
for {
daemon.SdNotify(false, "WATCHDOG=1")
time.Sleep(10 * time.Second)
}
}()
}
for {
ip := getMyExternalIP()
if ip == "" {
log.Printf("IP empty, nothing to update")
time.Sleep(intervalSleep)
continue
}
log.Printf("IP: %s", ip)
if ip == lastIP {
log.Print("Same IP, nothing to do")
time.Sleep(intervalSleep)
continue
}
if !setIPinAWS(*recordSet, ip, *zoneID) {
log.Print("Error, setting IP")
time.Sleep(intervalSleep)
continue
}
lastIP = ip
time.Sleep(intervalSleep)
}
}