wehub-resource-sync
88 lines
2.7 KiB
Python
88 lines
2.7 KiB
Python
"""Facilitates communication between processes."""
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import logging
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import multiprocessing as mp
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import threading
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from collections.abc import Callable
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from multiprocessing.synchronize import Event as MpEvent
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from typing import Any
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import zmq
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from frigate.comms.base_communicator import Communicator
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logger = logging.getLogger(__name__)
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SOCKET_REP_REQ = "ipc:///tmp/cache/comms"
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class InterProcessCommunicator(Communicator):
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def __init__(self) -> None:
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self.context = zmq.Context()
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self.socket = self.context.socket(zmq.REP)
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self.socket.bind(SOCKET_REP_REQ)
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self.stop_event: MpEvent = mp.Event()
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def publish(self, topic: str, payload: Any, retain: bool = False) -> None:
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"""There is no communication back to the processes."""
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pass
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def subscribe(self, receiver: Callable) -> None:
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self._dispatcher = receiver
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self.reader_thread = threading.Thread(target=self.read)
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self.reader_thread.start()
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def read(self) -> None:
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while not self.stop_event.is_set():
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while True: # load all messages that are queued
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has_message, _, _ = zmq.select([self.socket], [], [], 1)
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if not has_message:
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break
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try:
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raw = self.socket.recv_json(flags=zmq.NOBLOCK)
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if isinstance(raw, list):
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(topic, value) = raw
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response = self._dispatcher(topic, value)
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else:
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logging.warning(
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f"Received unexpected data type in ZMQ recv_json: {type(raw)}"
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)
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response = None
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if response is not None:
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self.socket.send_json(response)
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else:
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self.socket.send_json([])
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except zmq.ZMQError:
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break
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def stop(self) -> None:
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self.stop_event.set()
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self.reader_thread.join()
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self.socket.close(linger=0)
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self.context.destroy(linger=0)
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class InterProcessRequestor:
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"""Simplifies sending data to InterProcessCommunicator and getting a reply."""
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def __init__(self) -> None:
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self.context = zmq.Context()
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self.socket = self.context.socket(zmq.REQ)
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self.socket.connect(SOCKET_REP_REQ)
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def send_data(self, topic: str, data: Any) -> Any:
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"""Sends data and then waits for reply."""
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try:
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self.socket.send_json((topic, data))
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return self.socket.recv_json()
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except zmq.ZMQError:
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return ""
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def stop(self) -> None:
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self.socket.close(linger=0)
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self.context.destroy(linger=0)
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