SIENTIAPDE-988

Refactor OpcManager initialization and unsubscribe method; enhance logging

- Removed the `initialize_from_config` method from `OpcManager` class and adjusted the constructor to handle configuration directly.
- Improved the `unsubscribe` method to include detailed logging for non-existent subscriptions.
- Updated tests in `test_opc_manager.py` to reflect changes in the `OpcManager` class.
- Commented out Docker-related fixtures in `conftest.py` for potential future use.
- Enhanced test coverage in `test_single_node.py` and `test_data_manager.py` with additional scenarios and assertions.
- Introduced new methods in `Ingestor` and `IngestorManager` classes to manage server subscriptions and leases more effectively.
- Added new tests for `Ingestor` class to validate initialization and slot management logic.
- Implemented logging improvements across various classes to ensure better traceability of actions and errors.

ingestor/managers/data_manager.py

@@ -7,6 +7,19 @@ from kafka.errors import NoBrokersAvailable
 
 class DataManager():
     def __init__(self, kafka_servers: str, logger: Logger) -> None:
+        """
+        Initializes the DataManager instance with a Kafka producer.
+        This constructor attempts to establish a connection to the specified Kafka servers
+        and initializes a Kafka producer for sending messages. It retries the connection
+        up to 3 times if the Kafka servers are unavailable.
+        Args:
+            kafka_servers (str): A comma-separated string of Kafka server addresses.
+            logger (Logger): A logger instance for logging messages.
+        Raises:
+            NoBrokersAvailable: If the connection to Kafka servers fails after 3 attempts.
+        """
+
+        self.kafka_producer = None
         for i in range(0, 3):
             logger.info(
                 f"Trying ({i}) to initializing DataManager with Kafka servers: {kafka_servers}")
@@ -36,8 +49,11 @@ class DataManager():
     def __del__(self):
         """Destructor to close the producer connection."""
         print("Closing Kafka producer...")
-        self.kafka_producer.flush()
-        self.kafka_producer.close()
+        if self.kafka_producer:
+            self.kafka_producer.flush(timeout=10)
+            self.kafka_producer.close()
+        else:
+            print("Kafka producer is already closed or not initialized.")
 
     def delivery_report(self, msg: str):
         """Callback for delivery reports from Kafka."""