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BaseEventDispatcher.py 4.55 KiB
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    # Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #      http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    
    # See usage example below
    
    import logging, queue, threading, time
    from typing import Any, Callable, Optional
    from common.proto.context_pb2 import DeviceEvent, Empty, EventTypeEnum, LinkEvent
    from common.tools.grpc.BaseEventCollector import BaseEventCollector
    from common.tools.grpc.Tools import grpc_message_to_json_string
    from context.client.ContextClient import ContextClient
    
    LOGGER = logging.getLogger(__name__)
    
    class BaseEventDispatcher(threading.Thread):
        def __init__(
            self, events_queue : queue.PriorityQueue,
            terminate : Optional[threading.Event] = None
        ) -> None:
            super().__init__(daemon=True)
            self._events_queue = events_queue
            self._terminate = threading.Event() if terminate is None else terminate
    
        def stop(self):
            self._terminate.set()
    
        def _get_event(self, block : bool = True, timeout : Optional[float] = 0.5) -> Optional[Any]:
            try:
                _, event = self._events_queue.get(block=block, timeout=timeout)
                return event
            except queue.Empty:
                return None
    
        def _get_dispatcher(self, event : Any) -> Optional[Callable]:
            object_name = str(event.__class__.__name__).lower().replace('event', '')
            event_type  = EventTypeEnum.Name(event.event.event_type).lower().replace('eventtype_', '')
    
            method_name = 'dispatch_{:s}_{:s}'.format(object_name, event_type)
            dispatcher  = getattr(self, method_name, None)
            if dispatcher is not None: return dispatcher
    
            method_name = 'dispatch_{:s}'.format(object_name)
            dispatcher  = getattr(self, method_name, None)
            if dispatcher is not None: return dispatcher
    
            method_name = 'dispatch'
            dispatcher  = getattr(self, method_name, None)
            if dispatcher is not None: return dispatcher
    
            return None
    
        def run(self) -> None:
            while not self._terminate.is_set():
                event = self._get_event()
                if event is None: continue
    
                dispatcher = self._get_dispatcher(event)
                if dispatcher is None:
                    MSG = 'No dispatcher available for Event({:s})'
                    LOGGER.warning(MSG.format(grpc_message_to_json_string(event)))
                    continue
    
                dispatcher(event)
    
    class MyEventDispatcher(BaseEventDispatcher):
        def dispatch_device_create(self, device_event : DeviceEvent) -> None:
            MSG = 'Processing Device Create: {:s}'
            LOGGER.info(MSG.format(grpc_message_to_json_string(device_event)))
    
        def dispatch_device_update(self, device_event : DeviceEvent) -> None:
            MSG = 'Processing Device Update: {:s}'
            LOGGER.info(MSG.format(grpc_message_to_json_string(device_event)))
    
        def dispatch_device_remove(self, device_event : DeviceEvent) -> None:
            MSG = 'Processing Device Remove: {:s}'
            LOGGER.info(MSG.format(grpc_message_to_json_string(device_event)))
    
        def dispatch_link(self, link_event : LinkEvent) -> None:
            MSG = 'Processing Link Create/Update/Remove: {:s}'
            LOGGER.info(MSG.format(grpc_message_to_json_string(link_event)))
    
        def dispatch(self, event : Any) -> None:
            MSG = 'Processing any other Event: {:s}'
            LOGGER.info(MSG.format(grpc_message_to_json_string(event)))
    
    def main() -> None:
        logging.basicConfig(level=logging.INFO)
    
        context_client = ContextClient()
        context_client.connect()
    
        event_collector = BaseEventCollector()
        event_collector.install_collector(context_client.GetDeviceEvents,  Empty(), log_events_received=True)
        event_collector.install_collector(context_client.GetLinkEvents,    Empty(), log_events_received=True)
        event_collector.install_collector(context_client.GetServiceEvents, Empty(), log_events_received=True)
        event_collector.start()
    
        event_dispatcher = MyEventDispatcher(event_collector.get_events_queue())
        event_dispatcher.start()
    
        time.sleep(60)
    
        event_dispatcher.stop()
        event_collector.stop()
        context_client.close()
    
    if __name__ == '__main__':
        main()