dns/show: introduce writeRecords() helper

to print a whole []libdns.Record

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/dns/show.go

@@ -14,20 +14,24 @@ import (
 
 // Show shows current DNS entries
 func (mgr *Manager) Show(ctx context.Context, names ...string) error {
-	var buf bytes.Buffer
-
 	recs, err := mgr.GetRecords(ctx, names...)
 	if err != nil {
 		return core.Wrap(err, "GetRecords")
 	}
 
+	return writeRecords(recs, os.Stdout)
+}
+
+func writeRecords(recs []libdns.Record, w io.Writer) error {
+	var buf bytes.Buffer
+
 	for _, rr := range recs {
 		_ = fmtRecord(&buf, rr)
 		_, _ = buf.WriteRune('\n')
 	}
 	_, _ = fmt.Fprintf(&buf, "; %v records\n", len(recs))
 
-	_, err = buf.WriteTo(os.Stdout)
+	_, err := buf.WriteTo(w)
 	return err
 }