Files
netbox-dns-updater/netbox-dns-updater.go

139 lines
3.5 KiB
Go

package main
import (
"encoding/json"
"flag"
"fmt"
"io"
"log"
"net/http"
"net/url"
"os"
"os/exec"
"path"
"strings"
)
type IPAddress struct {
Address string `json:"address"`
DNSName string `json:"dns_name"`
}
type NetBoxResponse struct {
Results []IPAddress `json:"results"`
}
func FetchNetboxIPAddresses(apiBaseURL, token string) ([]IPAddress, error) {
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
}
req.Header.Set("Accept", "application/json")
req.Header.Set("Authorization", "Token "+token)
resp, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
body, _ := io.ReadAll(resp.Body)
return nil, fmt.Errorf("unexpected status: %s, body: %s", resp.Status, string(body))
}
var nbResp NetBoxResponse
decoder := json.NewDecoder(resp.Body)
if err := decoder.Decode(&nbResp); err != nil {
return nil, err
}
// Filter out entries with empty DNSName and strip CIDR from Address
var filtered []IPAddress
for _, ip := range nbResp.Results {
if ip.DNSName != "" {
ip.Address = strings.Split(ip.Address, "/")[0]
filtered = append(filtered, ip)
}
}
return filtered, nil
}
func CreateDnsMasqConfig(writeConfig bool) {
token := os.Getenv("NETBOX_TOKEN")
if token == "" {
home := os.Getenv("HOME")
paths := []string{
home + "/.netbox/token",
"/etc/netbox/token",
}
for _, path := range paths {
data, err := os.ReadFile(path)
if err == nil {
token = strings.TrimSpace(string(data))
break
}
}
if token == "" {
log.Fatal("NETBOX_TOKEN not set and no token file found")
}
}
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() && !writeConfig {
file, err := os.Create(dir + "/netbox.conf")
if err != nil {
log.Fatalf("Failed to create netbox.conf: %v", err)
}
defer file.Close()
for _, ip := range ips {
fmt.Fprintf(file, "address=/%s/%s\n", ip.DNSName, ip.Address)
}
} else {
for _, ip := range ips {
fmt.Printf("address=/%s/%s\n", ip.DNSName, ip.Address)
}
}
}
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(&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(false)
cmd := exec.Command("systemctl", "restart", "dnsmasq.service")
if err := cmd.Run(); err != nil {
log.Printf("Failed to restart dnsmasq.service: %v", err)
w.Write([]byte("\nWarning: Failed to restart dnsmasq.service.\n"))
}
w.Write([]byte("DNSMasq config updated."))
})
log.Printf("Starting web service on %s...", *listenAddr)
if err := http.ListenAndServe(*listenAddr, nil); err != nil {
log.Fatalf("Failed to start server: %v", err)
}
}