Initial Commit

pkg/updater/updater.go

@@ -0,0 +1,72 @@
+package updater
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+
+	"git.cryptic.systems/volker.raschek/dyndns-client/pkg/types"
+)
+
+type Updater interface {
+	AddRecord(ctx context.Context, name string, ttl uint, recordType string, data string) error
+	DeleteRecord(ctx context.Context, name string, recordType string) error
+	PruneRecords(ctx context.Context, name string) error
+}
+
+type NSUpdate struct {
+	server  string
+	tsigKey *types.TSIGKey
+}
+
+func (u *NSUpdate) AddRecord(ctx context.Context, name string, ttl uint, recordType string, data string) error {
+	nsUpdateCmd := ""
+	switch recordType {
+	case "A", "AAAA":
+		nsUpdateCmd = fmt.Sprintf("update add %v %v IN %v %v", name, ttl, recordType, data)
+	case "TXT":
+		nsUpdateCmd = fmt.Sprintf("update add %v %v IN %v \"%v\"", name, ttl, recordType, data)
+	default:
+		return fmt.Errorf("RecordType %v not supported", recordType)
+	}
+
+	return u.execute(ctx, nsUpdateCmd)
+}
+
+func (u *NSUpdate) DeleteRecord(ctx context.Context, name string, recordType string) error {
+	nsUpdateCmd := fmt.Sprintf("update delete %v IN %v", name, recordType)
+	return u.execute(ctx, nsUpdateCmd)
+}
+
+func (u *NSUpdate) execute(ctx context.Context, nsUpdateCmd string) error {
+	body := fmt.Sprintf("server %v\n%v\nsend\nquit", u.server, nsUpdateCmd)
+
+	errBuffer := new(bytes.Buffer)
+
+	cmd := exec.CommandContext(ctx, "nsupdate", "-y", fmt.Sprintf("%v:%v:%v", u.tsigKey.Algorithm, u.tsigKey.Name, u.tsigKey.Secret))
+	// cmd.Stdout = os.Stdout
+	cmd.Stderr = bufio.NewWriter(errBuffer)
+	cmd.Stdin = strings.NewReader(body)
+
+	err := cmd.Run()
+	if err != nil {
+		return fmt.Errorf("nsupdate error %w: %v", err, errBuffer.String())
+	}
+
+	return nil
+}
+
+func (u *NSUpdate) PruneRecords(ctx context.Context, name string) error {
+	nsUpdateCmd := fmt.Sprintf("update delete %v", name)
+	return u.execute(ctx, nsUpdateCmd)
+}
+
+func NewNSUpdate(server string, tsigKey *types.TSIGKey) (Updater, error) {
+	return &NSUpdate{
+		server:  server,
+		tsigKey: tsigKey,
+	}, nil
+}