Merge pull request #8 from jlentink/feature/dns-lookup

Feature/dns lookup

Dockerfile

@@ -1,4 +1,5 @@
 FROM alpine:latest
 
+RUN apk add --no-cache tzdata
 COPY go-transip-dyndns /usr/bin
 CMD ["/usr/bin/go-transip-dyndns", "update", "-k"]

README.md

@@ -13,6 +13,7 @@ Is a small little executable that will update a domain record of your choice tha
 7. run `go-transip-dyndns create` to create the record
 8. run `go-transip-dyndns validate` to see if all is 👍
 9. You are set. Well done!
+10. For a docker install see [Docker](#docker) section
 
 
 ## The configuration file
@@ -44,7 +45,7 @@ end of the certificate. Ensure you don't put any spaces in the key structure to
     ...Your certificate data...
     -----END PRIVATE KEY-----"""
 
-#### TXT, MX etc records.
+#### TXT, records.
 These records are handy and can have more markup than just an IP. For this purpose you have the ability to
 completly format the record and just inject the IP addresses. This can be done to inject a ip via the tags:
 
@@ -168,6 +169,34 @@ Binaries are available for download in multiple formats
 
 Download them [here](https://github.com/jlentink/go-transip-dyndns/releases/latest).
 
+## Docker
+For easy usage I personally run it via [docker-compose](https://docs.docker.com/compose/) with a file similar to the one shown below. 
+
+    version: '3.3'
+    services:
+      go-transip-dyndns:
+        image: jlentink/go-transip-dyndns:latest
+        container_name: go-transip-dyndns
+        volumes:
+          - ./go-transip-dyndns.toml:/etc/go-transip-dyndns.toml
+        restart: unless-stopped
+
+### Verify the setup
+Verify the setup by running the following command in the terminal where the docker-compose file is stored.
+It will verify the setup and output the results
+
+    docker-compose run --rm --entrypoint /usr/bin/go-transip-dyndns go-transip-dyndns -v verify
+
+###  Run create records
+To create the initial records run:
+
+    docker-compose run --rm --entrypoint /usr/bin/go-transip-dyndns go-transip-dyndns -v create
+
+### start the client
+Now all is created start the client as a deamon.
+
+    docker-compose up go-transip-dyndns -d
+
 ## No association with Transip
 This tool has been created for me own comfort. There is no association with Transip. But I would like to thank TransIP for there fine service!
 

docker/docker-compose.yml

@@ -1,8 +1,8 @@
 version: '3.3'
 services:
-  dyndns:
+  go-transip-dyndns:
     image: jlentink/go-transip-dyndns:latest
-    container_name: dyndns
-    build: .
+    container_name: go-transip-dyndns
     volumes:
-     - .:/etc/go-transip-dyndns
+      - ./go-transip-dyndns.toml:/etc/go-transip-dyndns.toml
+    restart: unless-stopped

internal/config/configObject.go

@@ -1,5 +1,7 @@
 package config
 
+import "strings"
+
 type ConfigObject struct {
 	General General  `toml:"general"`
 	Account Account  `toml:"account"`
@@ -21,3 +23,7 @@ type Record struct {
 	TTL      int    `toml:"ttl"`
 	Type     string `toml:"type"`
 }
+
+func (r *Record) GetType() string {
+	return strings.ToUpper(r.Type)
+}

internal/transipClient/createRecord.go

@@ -31,9 +31,8 @@ func CreateRecord(record config.Record) error {
 	if err != nil {
 		return err
 	}
-	getDomainRepo().AddDNSEntry(record.Hostname, entry)
+	return getDomainRepo().AddDNSEntry(record.Hostname, entry)
 
-	return nil
 }
 
 func createDNSEntry(record config.Record) (domain.DNSEntry, error) {
@@ -53,7 +52,8 @@ func createDNSEntry(record config.Record) (domain.DNSEntry, error) {
 	case "CNAME":
 		fallthrough
 	case "MX":
-		fallthrough
+		entry, err = createGenericEntry(record)
+		//fallthrough
 	case "TXT":
 		fallthrough
 	case "SRV":
@@ -74,7 +74,7 @@ func createAEntry(record config.Record) (domain.DNSEntry, error) {
 	entry := domain.DNSEntry{
 		Name:    record.Entry,
 		Expire:  record.TTL,
-		Type:    record.Type,
+		Type:    record.GetType(),
 		Content: ip.IP,
 	}
 	return entry, nil
@@ -92,7 +92,7 @@ func createAAAAEntry(record config.Record) (domain.DNSEntry, error) {
 	entry := domain.DNSEntry{
 		Name:    record.Entry,
 		Expire:  record.TTL,
-		Type:    record.Type,
+		Type:    record.GetType(),
 		Content: ip.IP,
 	}
 	return entry, nil
@@ -135,7 +135,7 @@ func createGenericEntry(record config.Record) (domain.DNSEntry, error) {
 	entry := domain.DNSEntry{
 		Name:    record.Entry,
 		Expire:  record.TTL,
-		Type:    record.Type,
+		Type:    record.GetType(),
 		Content: buf.String(),
 	}
 	return entry, nil

internal/transipClient/updateRecord.go

@@ -3,14 +3,78 @@ package transipClient
 import (
 	"github.com/transip/gotransip/v6/domain"
 	"go-transip-dyndns/internal/config"
+	"go-transip-dyndns/internal/logger"
+	"net"
 )
 
+func constructHostname(entry domain.DNSEntry, record config.Record) string {
+	hostname := ""
+	if entry.Name != "@" {
+		hostname += entry.Name + "."
+	}
+	hostname += record.Hostname
+	return hostname
+}
+
+func dnsAChanged(entry domain.DNSEntry, record config.Record) bool {
+	ips, err := net.LookupIP(constructHostname(entry, record))
+	if err != nil {
+		logger.Get().Debug("Error fetching DNS record. (%s)\n", err.Error())
+		return true
+	}
+	for _, ip := range ips {
+		if record.GetType() == "A" && ip.String() == entry.Content {
+			logger.Get().Debug("DNS [A] record has not been changed.\n")
+			return false
+		}
+		if record.GetType() == "AAAA" && ip.String() == entry.Content {
+			logger.Get().Debug("DNS [AAAA] record has not been changed.\n")
+			return false
+		}
+
+	}
+	return true
+}
+
+func dnsTXTChanged(entry domain.DNSEntry, record config.Record) bool {
+	txts, err := net.LookupTXT(constructHostname(entry, record))
+	if err != nil {
+		logger.Get().Debug("Error fetching DNS record. (%s)\n", err.Error())
+		return true
+	}
+	for _, txt := range txts {
+		if txt == entry.Content {
+			logger.Get().Debug("DNS [TXT] record has not been changed.\n")
+			return false
+		}
+
+	}
+	return true
+}
+
+func dnsChanged(entry domain.DNSEntry, record config.Record) bool {
+	switch entry.Type {
+	case "A":
+		fallthrough
+	case "AAAA":
+		return dnsAChanged(entry, record)
+	case "TXT":
+		return dnsTXTChanged(entry, record)
+	default:
+		return true
+	}
+}
+
 func UpdateRecord(record config.Record) (*domain.DNSEntry, error) {
 	entry, err := createDNSEntry(record)
 	if err != nil {
 		return nil, err
 	}
 
+	if !dnsChanged(entry, record) {
+		return nil, NotChangedError
+	}
+
 	dnsRecord, err := FindRecord(record.Hostname, record.Type, record.Entry)
 	if err != nil {
 		return nil, NotFoundError

main.go

@@ -64,12 +64,12 @@ func main() {
 	}
 
 	updateCmd := &cobra.Command{
-		Use:     "update",
-		Short:   "Update ip address on Transip DNS to current public ip (default command)",
-		Long:    "Use the current ip to update to a record in the TransIP dns.\nAllowing for easy updating when your ip changes.",
-		Example: "",
-
-		Run: commands.Update,
+		Use:              "update",
+		Short:            "Update ip address on Transip DNS to current public ip (default command)",
+		Long:             "Use the current ip to update to a record in the TransIP dns.\nAllowing for easy updating when your ip changes.",
+		Example:          "",
+		PersistentPreRun: commands.PreRun,
+		Run:              commands.Update,
 	}
 	updateCmd.PersistentFlags().BoolVarP(&keepRunning, "keep-alive", "k", false, "keep running continuously.")