manager/kafka_client.py: backup files only when they exists

diff --git a/python/knot_resolver/manager/kafka_client.py b/python/knot_resolver/manager/kafka_client.py
index 1fba18a2f9fd90cc50ca436ee0f717c154bd8a9b..2b9d448a43af93e7ad068c75b2af8022c392b7ee 100644 (file)
--- a/python/knot_resolver/manager/kafka_client.py
+++ b/python/knot_resolver/manager/kafka_client.py
@@ -40,7 +40,7 @@ if KAFKA_LIB:
             if self._consumer:
                 self._consumer.close()
 
-        def _consume(self) -> None:  # noqa: PLR0915
+        def _consume(self) -> None:  # noqa: PLR0912, PLR0915
             if not self._consumer:
                 return
 
@@ -56,6 +56,8 @@ if KAFKA_LIB:
                         # messages without key
                         # config
                         if not key:
+                            logger.info("Received configuration message")
+
                             config_orig = self._config.get_unparsed_data()
                             parsed = parse_json(value)
                             config_new = data_combine(config_orig, parsed)
@@ -63,7 +65,9 @@ if KAFKA_LIB:
                             file_path = self._config.kafka.files_dir.to_path() / "config.json"
                             file_path_tmp = f"{file_path}.tmp"
                             file_path_backup = f"{file_path}.backup"
-                            shutil.copy(file_path, file_path_backup)
+
+                            if file_path.exists():
+                                shutil.copy(file_path, file_path_backup)
                             with open(file_path_tmp, "w") as file:
                                 file.write(value)
 
@@ -85,6 +89,7 @@ if KAFKA_LIB:
                                 logger.error(f"Failed to apply new config:\n{response.body}")
                                 continue
                             os.replace(file_path_tmp, file_path)
+                            logger.info(f"Successfully applied config, saved to '{file_path}'")
                             continue
 
                         # messages with key
@@ -114,11 +119,12 @@ if KAFKA_LIB:
                             logger.debug(f"Saved part {file_part} of data to '{file_path_tmp}' file")
                         # received END of data
                         elif file_part and file_part == "END":
-                            shutil.copy(file_path, file_path_backup)
-                            logger.debug(f"Created backup of '{file_path_backup}' file")
+                            if file_path.exists():
+                                shutil.copy(file_path, file_path_backup)
+                                logger.debug(f"Created backup of '{file_path_backup}' file")
 
-                            os.replace(file_path, file_path_tmp)
-                            logger.info(f"Saved data to '{file_path}'")
+                            os.replace(file_path_tmp, file_path)
+                            logger.info(f"Saved file data to '{file_path}'")
 
                             # trigger delayed configuration renew
                             trigger_renew(self._config)