Added dry-run option and refactered FetchNetboxIPAddresses to accept API Base URL.

netbox-dns-updater.go

@@ -7,8 +7,10 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"net/url"
 	"os"
 	"os/exec"
+	"path"
 	"strings"
 )
 
@@ -21,8 +23,10 @@ type NetBoxResponse struct {
 	Results []IPAddress `json:"results"`
 }
 
-func FetchNetboxIPAddresses(apiURL, token string) ([]IPAddress, error) {
+func FetchNetboxIPAddresses(apiBaseURL, token string) ([]IPAddress, error) {
-	req, err := http.NewRequest("GET", apiURL, nil)
+	u, _ := url.Parse(apiBaseURL)
+	u.Path = path.Join(u.Path, "ipam/ip-addresses")
+	req, err := http.NewRequest("GET", u.String(), nil)
 	if err != nil {
 		return nil, err
 	}
@@ -57,7 +61,7 @@ func FetchNetboxIPAddresses(apiURL, token string) ([]IPAddress, error) {
 	return filtered, nil
 }
 
-func CreateDnsMasqConfig() {
+func CreateDnsMasqConfig(writeConfig bool) {
 	token := os.Getenv("NETBOX_TOKEN")
 	if token == "" {
 		home := os.Getenv("HOME")
@@ -77,13 +81,13 @@ func CreateDnsMasqConfig() {
 		}
 	}
 
-	ips, err := FetchNetboxIPAddresses(apiURL, token)
+	ips, err := FetchNetboxIPAddresses(apiBaseURL, token)
 	if err != nil {
 		log.Fatalf("Error fetching IP addresses: %v", err)
 	}
 
 	dir := "/etc/dnsmasq.d"
-	if stat, err := os.Stat(dir); err == nil && stat.IsDir() {
+	if stat, err := os.Stat(dir); err == nil && stat.IsDir() && !writeConfig {
 		file, err := os.Create(dir + "/netbox.conf")
 		if err != nil {
 			log.Fatalf("Failed to create netbox.conf: %v", err)
@@ -99,20 +103,27 @@ func CreateDnsMasqConfig() {
 	}
 }
 
-var apiURL string
+var apiBaseURL string
 
 func main() {
 	listenAddr := flag.String("listen", ":8080", "address and port to listen on (e.g. :8080 or 127.0.0.1:8080)")
-	flag.StringVar(&apiURL, "api-url", "https://netbox.koszewscy.waw.pl/api/ipam/ip-addresses/", "NetBox API URL to fetch IP addresses")
+	flag.StringVar(&apiBaseURL, "api-url", "https://netbox.koszewscy.waw.pl/api", "NetBox API URL to fetch IP addresses")
+	dryRun := flag.Bool("dry-run", false, "if set, do not write to dnsmasq config file, just print the output")
 	flag.Parse()
 
+	if *dryRun {
+		log.Println("Dry run mode enabled, not writing to dnsmasq config file.")
+		CreateDnsMasqConfig(true)
+		return
+	}
+
 	http.HandleFunc("/update-dnsmasq", func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodGet {
 			w.WriteHeader(http.StatusMethodNotAllowed)
 			w.Write([]byte("Method not allowed"))
 			return
 		}
-		CreateDnsMasqConfig()
+		CreateDnsMasqConfig(false)
 		cmd := exec.Command("systemctl", "restart", "dnsmasq.service")
 		if err := cmd.Run(); err != nil {
 			log.Printf("Failed to restart dnsmasq.service: %v", err)