SIENTIAPDE-1312

SIENTIAPDE-1318 Enhance OpcManager disconnection handling

- Introduced a disconnection_fallback method to attempt multiple disconnects from the OPC UA server, improving reliability.
- Updated error handling during connection attempts to ensure proper logging and notification of disconnection failures.
- Refactored disconnect method to utilize the new fallback mechanism and maintain metrics accurately.

ingestor/managers/opc_manager.py

@@ -1,5 +1,7 @@
+import asyncio
 import json
 from pathlib import Path
+import traceback
 
 from asyncua import Client
 from asyncua.crypto.security_policies import SecurityPolicyBasic256
@@ -208,9 +210,8 @@ class OpcManager(BaseActivity):
             ).set(1)
             self.logger.info(f'Connection to {self.name} successful.')
         except Exception as e:
-            if self.client:
             try:
-                    await self.client.disconnect()
+                await self.disconnect()
             except Exception as internal_e:
                 self.logger.error(f'And error occurred while creating connection from {self.name}, and an exception occurred while disconnecting: {internal_e}')
 
@@ -333,6 +334,28 @@ class OpcManager(BaseActivity):
         del self.subscriptions[subscription]
         self.logger.info(f'Unsubscribed from {subscription}.')
 
+    async def disconnection_fallback(self) -> list:
+        """
+        Tries 5 times to disconnect from the OPC UA server, with a delay of 100ms x try.
+        """
+
+        assert self.client is not None
+        error_stack = []
+        for i in range(5):
+            try:
+                self.logger.info(f'Disconnecting from OPC UA server, attempt {i+1} of 5')
+                await self.client.disconnect()
+                return []
+            except Exception as e:
+                self.logger.error(f'Failed to disconnect from OPC UA server: {e}')
+                error_stack.append({
+                    'attempt': i+1,
+                    'error': str(e),
+                    'traceback': traceback.format_exc(),
+                })
+                await asyncio.sleep(0.1 * i)
+        return error_stack
+
     async def disconnect(self):
         """
         Disconnects from the OPC UA server.
@@ -363,20 +386,27 @@ class OpcManager(BaseActivity):
         except Exception as sub_error:
             self.logger.error(f'Failed to clean up subscription: {sub_error}')
 
-        # Inserir backoff para disconnect, emitindo métrica e alerta
-        try:
-            await self.client.disconnect()
-        except Exception as conn_error:
-            self.logger.error(f'Failed to disconnect from OPC UA server: {conn_error}')
         
-        finally:
+        errors = self.disconnection_fallback()
+
+        if errors:
+            self.send_notification(
+                metadata=self.metadata,
+                notification_id=f'OPC_DISCONNECTION_ERROR_{self.name}',
+                message=f'Failed to disconnect from OPC UA server {self.name} after 5 attempts',
+                block='opc_manager',
+                level=NotificationLevel.ERROR,
+                attachment_content=json.dumps(errors, indent=4),
+            )
+        else:
+            self.logger.warning('Disconnected from OPC UA server.')
+
         del self.client
         self.client = None
         metrics.OPC_CONNECTION_STATUS.labels(
             pod_id=self.pod_id, server_name=self.name, server_url=self.url
         ).set(0)
         metrics.OPC_TAGS_SUBSCRIBED.labels(pod_id=self.pod_id, server_name=self.name).set(0)
-            self.logger.warning('Disconnected from OPC UA server.')
 
     async def datachange_notification(self, node, _val, data):
         """