update refactoring and add new features

SYS/worker_manager.py

@@ -260,6 +260,11 @@ class WorkerLoggingHandler(logging.StreamHandler):
         super().close()
 
 
+_DEFAULT_STDOUT_FLUSH_BYTES = 4096
+_DEFAULT_STDOUT_FLUSH_INTERVAL = 0.75
+_REFRESH_THREAD_JOIN_TIMEOUT = 5
+
+
 class WorkerManager:
     """Manages persistent worker tasks using the central medios.db."""
 
@@ -284,8 +289,8 @@ class WorkerManager:
         self._stdout_buffer_sizes: Dict[Tuple[str, str], int] = {}
         self._stdout_buffer_steps: Dict[Tuple[str, str], Optional[str]] = {}
         self._stdout_last_flush: Dict[Tuple[str, str], float] = {}
-        self._stdout_flush_bytes = 4096
-        self._stdout_flush_interval = 0.75
+        self._stdout_flush_bytes = _DEFAULT_STDOUT_FLUSH_BYTES
+        self._stdout_flush_interval = _DEFAULT_STDOUT_FLUSH_INTERVAL
 
 
     def __enter__(self):
@@ -707,7 +712,7 @@ class WorkerManager:
         self._stop_refresh = True
         self._refresh_stop_event.set()
         if self.refresh_thread:
-            self.refresh_thread.join(timeout=5)
+            self.refresh_thread.join(timeout=_REFRESH_THREAD_JOIN_TIMEOUT)
             self.refresh_thread = None
 
     def _start_refresh_if_needed(self) -> None: