pipe-io-server/pipe_io_server.py

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2018-12-13 21:06:13 +00:00
from threading import Thread
from queue import Queue
from os import mkfifo, remove
from os.path import exists, join
from signal import signal, SIGTERM, SIGINT
from secrets import token_urlsafe
class PipeWriterThread(Thread):
def __init__(self, to_write_queue, pipe_path):
super().__init__()
self._to_write_queue = to_write_queue
self._pipe_path = pipe_path
def run(self):
while True:
message = self._to_write_queue.get(block=True)
if message is None:
break
with open(self._pipe_path, 'wb') as pipe:
pipe.write(message)
def stop(self):
self._to_write_queue.put(None)
self.join()
class PipeReaderThread(Thread):
_stop_sequence = b'stop_reading'
def __init__(self, results_queue, pipe_path):
super().__init__()
self._results_queue = results_queue
self._pipe_path = pipe_path
def run(self):
while True:
with open(self._pipe_path, 'rb') as pipe:
message = pipe.read()
if message == self._stop_sequence:
break
self._results_queue.put(message, block=True)
def stop(self):
with open(self._pipe_path, 'wb') as pipe:
pipe.write(self._stop_sequence)
self.join()
class PipeHandler:
def __init__(self, pipe_path):
self._pipe_path = pipe_path
def recreate(self):
self.remove()
mkfifo(self._pipe_path)
def remove(self):
if exists(self._pipe_path):
remove(self._pipe_path)
class PipeIOServer:
def __init__(self, in_pipe=None, out_pipe=None):
self.in_pipe, self.out_pipe = in_pipe, out_pipe
self._create_pipes()
self._message_queue = Queue()
self._io_threads = {
'reader': PipeReaderThread(self._message_queue, self.in_pipe),
'writer': PipeWriterThread(self._message_queue, self.out_pipe)
}
def _create_pipes(self):
if not self.in_pipe or not self.out_pipe:
pipe_id = token_urlsafe(6)
self.in_pipe = join('/tmp', f'in_pipe_{pipe_id}')
self.out_pipe = join('/tmp', f'out_pipe_{pipe_id}')
PipeHandler(self.in_pipe).recreate()
PipeHandler(self.out_pipe).recreate()
def run(self):
for thread in self._io_threads.values():
thread.start()
def stop(self):
for thread in self._io_threads.values():
thread.stop()
PipeHandler(self.in_pipe).remove()
PipeHandler(self.out_pipe).remove()
if __name__ == "__main__":
pipe_io = PipeIOServer()
signal(SIGTERM, lambda a, b: pipe_io.stop())
signal(SIGINT, lambda a, b: pipe_io.stop())
pipe_io.run()
print('Running pipe IO server with named pipes:')
print(f'Input: {pipe_io.in_pipe}')
print(f'Output: {pipe_io.out_pipe}')