dns-api: add debug endpoint

Change-Id: I7e2a6546884b43ad9b377d19b480efd52e905c32
diff --git a/core/dns-api/store.go b/core/dns-api/store.go
index 8dfd914..588a2f2 100644
--- a/core/dns-api/store.go
+++ b/core/dns-api/store.go
@@ -7,7 +7,7 @@
 )
 
 type RecordStore interface {
-	Log() error
+	All() (string, error)
 	Add(entry, txt string) error
 	AddARecord(entry, ip string) error
 	Delete(entry, txt string) error
@@ -21,14 +21,17 @@
 	db       string
 }
 
-func (s *fsRecordStore) Log() error {
+func (s *fsRecordStore) All() (string, error) {
 	r, err := s.fs.Reader(s.db)
 	if err != nil {
-		return err
+		return "", err
 	}
 	defer r.Close()
-	_, err = io.Copy(os.Stdout, r)
-	return err
+	ret, err := io.ReadAll(r)
+	if err != nil {
+		return "", err
+	}
+	return string(ret), nil
 }
 
 func (s *fsRecordStore) read() (*RecordsFile, error) {