add dual stack support

README.md

@@ -1,7 +1,7 @@
 # DIGITAL OCEAN DYNAMIC IP API CLIENT
 A simple script in Go language to automatically update Digital ocean DNS records if you have a dynamic IP. Since it can be compiled on any platform, you can use it along with raspberrypi etc.
 
-To find your Dynamic IP, this program will call out to https://diagnostic.opendns.com/myip.
+To find your Dynamic IP, this program will call out to https://ipv4bot.whatismyipaddress.com for ipv4 addresses and https://ipv6bot.whatismyipaddress.com for ipv6 addresses. This is to support dual-stack environments.
 
 ## requirements
 Requires Git and Go for building.
@@ -21,6 +21,8 @@ create a file ".digitalocean-dynamic-ip.json"(dot prefix to hide the file) and p
 {
   "apikey": "samplekeydasjkdhaskjdhrwofihsamplekey",
   "doPageSize" : 20,
+  "useIPv4": true,
+  "useIPv6": false,
   "domains": [
     {
       "domain": "example.com",
@@ -48,6 +50,8 @@ The TTL can optionally be updated if passed in the configuration. Digital Ocean
 
 If you want to reduce the number of calls made to the digital ocean API and have more than 20 DNS records in your domain, you can adjust the `doPageSize` parameter. By default, Digital Ocean returns 20 records per page.
 
+By default, the configuration checks both IPv4 and IPv6 addresses assuming your provider set up your connection as dual stack. If you know you only have ipv4 or ipv6 you can disable using one or the other in the config. To disable one or the other, set the `useIPv4` or `useIPv6` settings to `false`. If the options aren't present, or are set to `null`, then the configuration assumes a value of `true`.
+
 ```bash
 #run
 go build digitalocean-dynamic-ip.go

digitalocean-dynamic-ip.go

@@ -28,6 +28,8 @@ var config ClientConfig
 type ClientConfig struct {
 	APIKey     string   `json:"apiKey"`
 	DOPageSize int      `json:"doPageSize"`
+	UseIPv4    *bool    `json:"useIPv4"`
+	UseIPv6    *bool    `json:"useIPv6"`
 	Domains    []Domain `json:"domains"`
 }
 
@@ -111,14 +113,49 @@ func usage() {
 	))
 }
 
-//CheckLocalIP : get current IP of server.
-func CheckLocalIP() string {
-	currentIPRequest, err := http.Get("https://diagnostic.opendns.com/myip")
+//CheckLocalIPs : get current IP of server. checks both IPv4 and Ipv6 to support dual stack environments
+func CheckLocalIPs() (ipv4, ipv6 net.IP) {
+	var ipv4String, ipv6String string
+
+	if config.UseIPv4 == nil || *(config.UseIPv4) {
+		ipv4String, _ = getURLBody("https://ipv4bot.whatismyipaddress.com")
+		if ipv4String == "" {
+			log.Println("No IPv4 address found. Consider disabling IPv4 checks in the config `\"useIPv4\": false`")
+		} else {
+			ipv4 = net.ParseIP(ipv4String)
+			if ipv4 != nil {
+				// make sure we got back an actual ipv4 address
+				ipv4 = ipv4.To4()
+			}
+			if ipv4 == nil {
+				log.Printf("Unable to parse `%s` as an IPv4 address\n", ipv4String)
+			}
+		}
+	}
+
+	if config.UseIPv6 == nil || *(config.UseIPv6) {
+		ipv6String, _ = getURLBody("https://ipv6bot.whatismyipaddress.com")
+		if ipv6String == "" {
+			log.Println("No IPv6 address found. Consider disabling IPv6 checks in the config `\"useIPv6\": false`")
+		} else {
+			ipv6 = net.ParseIP(ipv6String)
+			if ipv6 == nil {
+				log.Printf("Unable to parse `%s` as an IPv4 address\n", ipv6String)
+			}
+		}
+	}
+	return ipv4, ipv6
+}
+
+func getURLBody(url string) (string, error) {
+	request, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer request.Body.Close()
+	body, err := ioutil.ReadAll(request.Body)
 	checkError(err)
-	defer currentIPRequest.Body.Close()
-	currentIPRequestParse, err := ioutil.ReadAll(currentIPRequest.Body)
-	checkError(err)
-	return string(currentIPRequestParse)
+	return string(body), nil
 }
 
 //GetDomainRecords : Get DNS records of current domain.
@@ -156,13 +193,7 @@ func getPage(url string) DOResponse {
 }
 
 // UpdateRecords : Update DNS records of domain
-func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
-	currentIP := ip.String()
-	isIpv6 := ip.To4() == nil
-	if !isIpv6 {
-		// make sure we are using a v4 format
-		currentIP = ip.To4().String()
-	}
+func UpdateRecords(domain string, ipv4, ipv6 net.IP, toUpdateRecords []DNSRecord) {
 	log.Printf("%s: %d to update\n", domain, len(toUpdateRecords))
 	updated := 0
 	doRecords := GetDomainRecords(domain)
@@ -174,17 +205,28 @@ func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
 	log.Printf("%s: %d DNS records found", domain, len(doRecords))
 	for _, toUpdateRecord := range toUpdateRecords {
 		if toUpdateRecord.Type != "A" && toUpdateRecord.Type != "AAAA" {
-			log.Fatalf("%s: Unsupported type (Only A and AAAA records supported) for updates %+v", domain, toUpdateRecord)
+			log.Printf("%s: Unsupported type (Only A and AAAA records supported) for updates %+v", domain, toUpdateRecord)
+			continue
 		}
-		if isIpv6 && toUpdateRecord.Type == "A" {
-			log.Fatalf("%s: You are trying to update an IPV4 A record with an IPV6 address: new ip: %s, config: %+v", domain, currentIP, toUpdateRecord)
+		if ipv4 == nil && toUpdateRecord.Type == "A" {
+			log.Printf("%s: You are trying to update an IPv4 A record with no IPv4 address: config: %+v", domain, toUpdateRecord)
+			continue
 		}
-		if !isIpv6 && toUpdateRecord.Type == "AAAA" {
-			log.Fatalf("%s: You are trying to update an IPV6 A record with an IPV4 address: new ip: %s, config: %+v", domain, currentIP, toUpdateRecord)
+		if ipv6 == nil && toUpdateRecord.Type == "AAAA" {
+			log.Printf("%s: You are trying to update an IPv6 AAAA record with no IPv6 address: config: %+v", domain, toUpdateRecord)
+			continue
 		}
 		if toUpdateRecord.ID > 0 {
 			// update the record directly. skip the extra search
-			log.Fatalf("%s: Unable to directly update records yet. Record: %+v", domain, toUpdateRecord)
+			log.Printf("%s: Unable to directly update records yet. Record: %+v", domain, toUpdateRecord)
+			continue
+		}
+
+		var currentIP string
+		if toUpdateRecord.Type == "A" {
+			currentIP = ipv4.String()
+		} else {
+			currentIP = ipv6.String()
 		}
 
 		log.Printf("%s: trying to update `%s` : `%s`", domain, toUpdateRecord.Type, toUpdateRecord.Name)
@@ -225,15 +267,17 @@ func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
 
 func main() {
 	config = GetConfig()
-	currentIP := CheckLocalIP()
-	ip := net.ParseIP(currentIP)
-	if ip == nil {
-		log.Fatalf("current IP address `%s` is not a valid IP address", currentIP)
+	currentIPv4, currentIPv6 := CheckLocalIPs()
+	if currentIPv4 == nil && currentIPv6 == nil {
+		log.Fatalf("current IP addresses are not a valid, or both are disabled in the config. Check you configuration and internet connection",
+			currentIPv4,
+			currentIPv6,
+		)
 	}
 	for _, domain := range config.Domains {
 		domainName := domain.Domain
 		log.Printf("%s: START\n", domainName)
-		UpdateRecords(domainName, ip, domain.Records)
+		UpdateRecords(domainName, currentIPv4, currentIPv6, domain.Records)
 		log.Printf("%s: END\n", domainName)
 	}
 }

digitalocean-dynamic-ip.sample.json

@@ -1,6 +1,8 @@
 {
   "apikey": "samplekeydasjkdhaskjdhrwofihsamplekey",
-  "doPageSize" : 20,
+  "doPageSize": 20,
+  "useIPv4": true,
+  "useIPv6": true,
   "domains": [
     {
       "domain": "example.com",