109 lines
3.1 KiB
Python
109 lines
3.1 KiB
Python
from threading import Thread
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from queue import Queue
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from os import mkfifo, remove, getpid, kill
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from os.path import exists, join
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from signal import SIGTERM
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from secrets import token_urlsafe
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from collections import namedtuple
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from abc import ABC, abstractmethod
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from traceback import print_exc
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class PipeWriterThread(Thread):
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def __init__(self, pipe_path):
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super().__init__()
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self._pipe_path = pipe_path
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self._write_queue = Queue()
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def write(self, message):
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self._write_queue.put(message, block=True)
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def run(self):
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while True:
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message = self._write_queue.get(block=True)
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if message is None:
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break
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with open(self._pipe_path, 'wb') as pipe:
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pipe.write(message)
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def stop(self):
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self._write_queue.put(None)
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self.join()
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class PipeReaderThread(Thread):
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_stop_sequence = b'stop_reading'
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def __init__(self, pipe_path, message_handler):
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super().__init__()
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self._message_handler = message_handler
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self._pipe_path = pipe_path
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def run(self):
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while True:
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with open(self._pipe_path, 'rb') as pipe:
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message = pipe.read()
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if message == self._stop_sequence:
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break
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try:
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self._message_handler(message)
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except: # pylint: disable=bare-except
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print_exc()
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kill(getpid(), SIGTERM)
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def stop(self):
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with open(self._pipe_path, 'wb') as pipe:
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pipe.write(self._stop_sequence)
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self.join()
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class PipeHandler:
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def __init__(self, *pipe_paths):
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self._pipe_paths = pipe_paths
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def recreate(self):
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self.remove()
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for pipe_path in self._pipe_paths:
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mkfifo(pipe_path)
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def remove(self):
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for pipe_path in self._pipe_paths:
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if exists(pipe_path):
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remove(pipe_path)
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class PipeIOServer(ABC):
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def __init__(self, in_pipe=None, out_pipe=None):
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self.in_pipe, self.out_pipe = in_pipe, out_pipe
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self._create_pipes()
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io_threads_dict = {
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'reader': PipeReaderThread(self.in_pipe, self._handle_message),
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'writer': PipeWriterThread(self.out_pipe)
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}
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IOThreadsTuple = namedtuple('IOThreadsTuple', sorted(io_threads_dict.keys()))
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self._io_threads = IOThreadsTuple(**io_threads_dict)
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def _create_pipes(self):
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if not self.in_pipe or not self.out_pipe:
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pipe_id = token_urlsafe(6)
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self.in_pipe = join('/tmp', f'in_pipe_{pipe_id}')
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self.out_pipe = join('/tmp', f'out_pipe_{pipe_id}')
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PipeHandler(self.in_pipe, self.out_pipe).recreate()
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@abstractmethod
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def _handle_message(self, message):
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raise NotImplementedError()
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def send(self, message):
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self._io_threads.writer.write(message)
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def run(self):
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for thread in self._io_threads:
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thread.start()
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def stop(self):
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for thread in self._io_threads:
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thread.stop()
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PipeHandler(self.in_pipe, self.out_pipe).remove()
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