refactor(gateway): drop dead error_stack and unused metadata from OpcConnectionPool (ponytail)

ingestor/connection/pool.py

@@ -1,5 +1,4 @@
 import asyncio
-import traceback
 
 from asyncua import Client
 from sientia_do.notifications.handlers import CoreNotificationHandler as NotificationHandler
@@ -23,10 +22,8 @@ class OpcConnectionPool(SientiaMonitoring):
         logger: Logger,
         notification_handler: NotificationHandler,
         metrics_controller: MetricsController,
-        metadata: dict | None = None,
     ):
         self.cert_provider = cert_provider
-        self.metadata = metadata or {}
         self.clock = MonotonicClock()
         self._connections: dict[str, tuple[Client, float]] = {}
         # ponytail: one Lock per server_id, never cleaned up — server set is
@@ -119,20 +116,15 @@ class OpcConnectionPool(SientiaMonitoring):
             tags={'pod_id': self.pod_id, 'server_name': server_id},
         )
 
-    async def _disconnect_with_retries(self, client: Client, server_id: str) -> list:
+    async def _disconnect_with_retries(self, client: Client, server_id: str) -> None:
         """Tries 5 times to disconnect, with a delay of 100ms x try (mirrors
         OpcManager.disconnection_fallback)."""
-        error_stack = []
         for i in range(5):
             try:
                 await client.disconnect()
-                return []
+                return
             except Exception as e:
                 self.logger.error(
                     f'Failed to disconnect from {server_id}, attempt {i + 1} of 5: {e}'
                 )
-                error_stack.append(
-                    {'attempt': i + 1, 'error': str(e), 'traceback': traceback.format_exc()}
-                )
                 await asyncio.sleep(0.1 * i)
-        return error_stack