sientia-dataops-opc-ingestor/ingestor/managers/opc_manager.py

import json
from pathlib import Path

from asyncua import Client
from asyncua.crypto.security_policies import SecurityPolicyBasic256
from sientia_do.notifications.handlers import CoreNotificationHandler as NotificationHandler
from sientia_do.notifications.models import NotificationLevel
from sientia_do.observability.logger import Logger
from sientia_do.temporal.activities.base import BaseActivity
from sientia_do.temporal.constants import DATETIME_FORMAT_WITH_TZ, OPC_TIMEZONE

import ingestor.metrics as metrics
from ingestor.managers.data_manager import DataManager


class OpcManager(BaseActivity):
    """
    Manages OPC UA server connections and tag subscriptions.

    The OpcManager is responsible for:
    - Establishing and maintaining secure connections to OPC UA servers
    - Managing tag subscriptions and data collection
    - Handling server reconnection and error recovery
    - Processing OPC data and forwarding it to the data manager
    - Monitoring connection health and performance metrics

    The manager supports both secure and unsecured connections, with optional
    certificate-based authentication for enhanced security.

    Args:
        name (str): Unique identifier for the OPC server
        url (str): OPC UA server endpoint URL
        data_manager (DataManager): Manager for data persistence and export
        logger (Logger): Logger instance for application logging
        server_uri (str): OPC UA server application URI
        notification_handler (NotificationHandler): Handler for sending notifications
        metadata (dict): Application metadata for notifications and tracking
        cert_path (str, optional): Path to client certificate file for secure connections
        private_key_path (str, optional): Path to client private key file
        server_cert_path (str, optional): Path to server certificate file for validation

    Attributes:
        url (str): OPC UA server endpoint URL
        name (str): Unique identifier for the OPC server
        server_uri (str): OPC UA server application URI
        data_queue (dict): Queue for buffering OPC data before processing
        non_receive_count (int): Counter for cycles without data reception
        client (Client): OPC UA client instance
        cert_path (str): Path to client certificate file
        private_key_path (str): Path to client private key file
        server_cert_path (str): Path to server certificate file
        nodes (dict): Dictionary of OPC node references
        subscriptions (dict): Active OPC subscriptions
        data_manager (DataManager): Manager for data persistence and export
        metadata (dict): Application metadata
    """

    def __init__(
        self,
        name: str,
        url: str,
        data_manager: DataManager,
        logger: Logger,
        server_uri: str,
        notification_handler: NotificationHandler,
        metadata: dict,
        cert_path: str = None,
        private_key_path: str = None,
        server_cert_path: str = None,
    ):
        self.url = url
        self.name = name
        self.server_uri = server_uri
        self.data_queue = {}
        self.non_receive_count = 0
        self.client = None
        self.cert_path = cert_path
        self.private_key_path = private_key_path
        self.server_cert_path = server_cert_path
        self.nodes = {}
        self.subscriptions = {}
        self.data_manager = data_manager
        self.metadata = metadata

        BaseActivity.__init__(
            self, logger=logger, notification_handler=notification_handler, set_error_counter=True
        )

        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)

    def __str__(self):
        """
        String representation of the OPC Manager.

        Returns:
            str: Human-readable representation showing server details and current state.
        """
        return (
            f'OpcManager(name={self.name}, url={self.url}, server_uri={self.server_uri})\n'
            f'nodes={self.nodes}, subscriptions={self.subscriptions}'
        )

    async def shutdown(self):
        """
        Comprehensive cleanup method for graceful shutdown.

        This method ensures proper cleanup of all OPC UA resources:
        - Closes active subscriptions
        - Disconnects from the OPC server
        - Releases allocated resources

        Should be called before the application terminates to prevent resource leaks
        and ensure clean disconnection from OPC servers.
        """
        try:
            await self.disconnect()
        except Exception as e:
            self.logger.error(f'Error during cleanup: {e}')

    async def set_security(self):
        """
        Configures the security settings for the OPC UA client.

        This method sets up the security policy, certificates, and timeouts
        required for establishing a secure connection with the OPC UA server.
        It implements Basic256 security policy with certificate-based authentication.

        Raises:
            ValueError: If either the certificate path or private key path is not provided.

        Security Settings:
            - Security Policy: Basic256
            - Secure Channel Timeout: 10,000,000 ms
            - Session Timeout: 10,000,000 ms

        The method configures:
            - Client application URI
            - Certificate-based authentication
            - Server certificate validation (if provided)
            - Connection timeouts for stability
        """

        if not all([self.cert_path, self.private_key_path]):
            raise ValueError(
                'Certificate and private key paths must be provided for secure connection.'
            )
        cert = Path(self.cert_path)
        private_key = Path(self.private_key_path)
        server_cert = Path(self.server_cert_path) if self.server_cert_path else None

        await self.client.set_application_uri(self.server_uri)
        self.logger.info('Setting security...')
        await self.client.set_security(
            SecurityPolicyBasic256,
            certificate=str(cert),
            private_key=str(private_key),
            server_certificate=str(server_cert),
        )
        await self.client.set_secure_channel_timeout(10000000)
        await self.client.set_session_timeout(10000000)

    async def connect(self):
        """
        Establishes a connection to the OPC server.

        This method initializes the OPC client using the provided URL and
        sets up security if a certificate path is specified. It then
        attempts to connect to the server and logs the connection status.

        The connection process includes:
        1. Client initialization with server URL
        2. Security configuration (if certificates are provided)
        3. Connection establishment
        4. Metrics recording for monitoring

        Raises:
            Exception: If the connection to the OPC server fails.

        Metrics:
            - OPC_CONNECTIONS_TOTAL: Incremented on connection attempt
            - OPC_CONNECTION_STATUS: Set to 1 on successful connection
        """

        metrics.OPC_CONNECTIONS_TOTAL.labels(pod_id=self.pod_id, server_name=self.name).inc()
        try:
            self.client = Client(self.url, watchdog_intervall=3600000)
            self.client.name = self.pod_id
            if self.cert_path:
                await self.set_security()
            self.logger.info(f'Starting connection to {self.name}...')
            await self.client.connect()
            metrics.OPC_CONNECTION_STATUS.labels(
                pod_id=self.pod_id, server_name=self.name, server_url=self.url
            ).set(1)
            self.logger.info(f'Connection to {self.name} successful.')
        except Exception as e:
            metrics.OPC_CONNECTION_STATUS.labels(
                pod_id=self.pod_id, server_name=self.name, server_url=self.url
            ).set(0)
            metrics.OPC_CONNECTIONS_FAILED.labels(pod_id=self.pod_id, server_name=self.name).inc()
            self.logger.error(f'Failed to connect to {self.name}: {e}')
            raise

    async def create_subscription(self, name: str, period: int = 500):
        """
        Creates a subscription with the specified monitoring period.

        This method establishes a subscription to monitor data changes or events
        from the OPC UA server. If the client is not connected, an exception is raised.

        Args:
            name (str): The name identifier for the subscription
            period (int, optional): The monitoring period in milliseconds. Defaults to 500 ms.

        Raises:
            ValueError: If the client is not connected.

        Side Effects:
            - Sets the `self.period` attribute to the specified or default period.
            - Creates a subscription and assigns it to `self.subscriptions[name]`.
            - Logs the creation of the subscription.
            - Increments subscription creation metrics.
        """

        if not self.client:
            raise ValueError('Client not connected. Call connect first.')
        try:
            p = period if period is not None else 500
            self.subscriptions[name] = await self.client.create_subscription(p, self)
            self.logger.info(f'Subscription {name} created on {self.name}.')
            metrics.OPC_SUBSCRIPTIONS_CREATED.labels(
                pod_id=self.pod_id, server_name=self.name, slot_name=name
            ).inc()
        except Exception as e:
            self.logger.error(f'Failed to create subscription {name} on {self.name}: {e}')
            raise

    async def subscribe(self, subscription: str, nodes: dict, collect_period: int):
        """
        Subscribes to a set of OPC UA nodes for data change notifications.

        This method adds the specified nodes to the subscription and configures
        their data collection rules based on the provided collection period and
        node-specific frequency.

        Args:
            subscription (str): The name of the subscription to use
            nodes (dict): A dictionary where keys are node identifiers and values are
                configurations for each node. Each configuration must include a 'frequency'
                key indicating the frequency of data collection in Hz.
            collect_period (int): The data collection period in seconds.

        Raises:
            ValueError: If the subscription has not been created by calling
                `create_subscription` prior to this method.

        Side Effects:
            - Updates internal node tracking and cycle rules
            - Establishes data change monitoring for specified nodes
            - Updates metrics for subscribed tags count
        """

        if not self.subscriptions.get(subscription):
            raise ValueError('Subscription not created. Call create_subscription first.')

        self.logger.info(f'Subscribing to {subscription} on {self.name}...')
        self.logger.info(f'Subscribing to nodes: {nodes}')
        addr_nodes = [self.client.get_node(n) for n in nodes]
        self.logger.debug(f'Addr nodes: {addr_nodes}')
        self.nodes.update(nodes)
        self.logger.debug(f'Nodes: {self.nodes}')
        metrics.OPC_TAGS_SUBSCRIBED.labels(pod_id=self.pod_id, server_name=self.name).set(
            len(self.nodes)
        )
        self.collect_period = collect_period

        for node, config in self.nodes.items():
            self.nodes[node]['cycle_rule'] = {
                'cycle_increment': collect_period * 1000 / float(config['frequency']),
                'cycle_count': 0,
            }

        await self.subscriptions[subscription].subscribe_data_change(addr_nodes)

    async def unsubscribe(self, subscription: str):
        """
        Unsubscribes from a given subscription.

        This method removes the specified subscription and cleans up associated
        resources. It handles cases where the subscription doesn't exist gracefully.

        Args:
            subscription (str): The name of the subscription to unsubscribe from.

        Logs:
            - A warning if the specified subscription does not exist.
            - An info message upon successful unsubscription.

        Behavior:
            - If the subscription exists, it is deleted and removed from the
              subscriptions dictionary.
            - If the subscription does not exist, no action is taken.
        """

        if not self.subscriptions.get(subscription):
            self.logger.warning(f"Subscription '{subscription}' not found. Cannot unsubscribe.")
            return
        await self.subscriptions[subscription].delete()
        del self.subscriptions[subscription]
        self.logger.info(f'Unsubscribed from {subscription}.')

    async def disconnect(self):
        """
        Disconnects from the OPC UA server.

        This method handles the disconnection process by deleting all subscriptions
        and disconnecting the client from the OPC UA server. It logs the disconnection
        process and handles any exceptions that may occur during cleanup.

        Raises:
            Exception: If an error occurs while deleting the subscription or disconnecting
                       from the OPC UA server, it logs the error details.

        Side Effects:
            - Deletes all active subscriptions
            - Disconnects the OPC client
            - Updates connection status metrics
            - Clears internal client reference
        """

        self.logger.warning('Disconnecting from OPC server')
        if self.client is None:
            self.logger.warning('Client already disconnected.')
            return
        try:
            for sub in self.subscriptions:
                await self.subscriptions[sub].delete()
            self.logger.warning('Deleted all subscriptions.')
        except Exception as sub_error:
            self.logger.error(f'Failed to clean up subscription: {sub_error}')

        try:
            await self.client.disconnect()
        except Exception as conn_error:
            self.logger.error(f'Failed to disconnect from OPC UA server: {conn_error}')
        finally:
            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):
        """
        Handles data change notifications for monitored OPC UA nodes.

        This method is triggered when a monitored node's value changes. It processes
        the notification, updates internal state, and publishes the data to the
        appropriate topics.

        Args:
            node (NodeId): The OPC UA node that triggered the data change notification.
            _val (Any): The new value of the node (unused in this implementation).
            data (DataChangeNotification): The data change notification object containing
                details about the change.

        Behavior:
            - Extracts the value and source timestamp from the monitored item.
            - Resets the cycle count for the node's cycle rule.
            - Resets the non-receive count.
            - Constructs a data dictionary containing the tag, tag name, timestamp, and value.
            - Publishes the data to all topics associated with the node.
        """

        # get data value
        monitored_item = data.monitored_item
        value = monitored_item.Value.Value.Value
        # source_timestamp
        source_timestamp = monitored_item.Value.SourceTimestamp.replace(tzinfo=OPC_TIMEZONE)
        tag = str(node)

        self.logger.debug(
            f'Data change notification received for tag:'
            f'{tag} after {self.nodes[tag]["cycle_rule"]["cycle_count"]} cycles'
        )

        self.nodes[tag]['cycle_rule']['cycle_count'] = 0
        self.non_receive_count = 0
        metrics.OPC_CYCLES_WITHOUT_DATA.labels(pod_id=self.pod_id, server_name=self.name).set(0)

        data = {
            'tag': tag,
            'name': self.nodes[str(node)]['tag_name'],
            'timestamp': source_timestamp.strftime(DATETIME_FORMAT_WITH_TZ),
            'value': value,
        }

        _a = [self.data_manager.publish(e, data) for e in self.nodes[tag]['topics']]

    def check_cycles(self):
        """
        Checks the cycle counts for all monitored nodes and sends
        notifications if thresholds are exceeded.

        This method iterates through all monitored nodes and updates their cycle counts based on
        configured increments. If a node's cycle count exceeds a threshold (5 cycles), it triggers
        a warning notification.

        Side Effects:
            - Updates cycle counts for all monitored nodes
            - Sends warning notifications for nodes exceeding cycle thresholds
        """
        for node, config in self.nodes.items():
            self.nodes[node]['cycle_rule']['cycle_count'] += config['cycle_rule']['cycle_increment']
            if self.nodes[node]['cycle_rule']['cycle_count'] >= 5:
                name = config['tag_name']
                cycles = self.nodes[node]['cycle_rule']['cycle_count']
                self.send_notification(
                    metadata=self.metadata,
                    notification_id=f'TAG_{node}:{name}_LISTENNING_STOPPED',
                    message=f'{cycles} cycles without receive from {node}:{name}',
                    block='opc_manager',
                    level=NotificationLevel.WARNING,
                )

    def check_opc_listenning(self) -> bool:
        """
        Checks the OPC connection and triggers notifications if the connection is lost.

        This method monitors the data reception health by tracking cycles without
        data. It sends notifications at different thresholds and can trigger
        reconnection attempts.

        Returns:
            bool: True if the connection is lost and reconnection should be attempted,
                  False otherwise.

        Side Effects:
            - Increments non-receive count
            - Updates metrics for cycles without data
            - Sends warning notifications at 5 cycles
            - Sends error notifications and triggers reconnection at 15 cycles
        """

        self.non_receive_count += 1
        metrics.OPC_CYCLES_WITHOUT_DATA.labels(pod_id=self.pod_id, server_name=self.name).set(
            self.non_receive_count
        )
        if self.non_receive_count >= 5:
            self.send_notification(
                metadata=self.metadata,
                notification_id=f'OPC_LISTENNING_STOPPED__{self.name}',
                message=f'{self.non_receive_count} cycles without '
                f'receive from OPC {self.name}. Tags: {json.dumps(self.nodes)}',
                block='opc_manager',
                level=NotificationLevel.ERROR,
            )
        if self.non_receive_count >= 15:
            metrics.OPC_RECONNECTIONS_TOTAL.labels(pod_id=self.pod_id, server_name=self.name).inc()
            self.send_notification(
                metadata=self.metadata,
                notification_id=f'OPC_CONNECTION_RETRY__{self.name}',
                message=f'Retrying to connect to server {self.name}',
                block='opc_manager',
                level=NotificationLevel.ERROR,
            )
            return True
        return False