pipe-io-server/pipe_io_server.py
2018-12-14 15:39:18 +01:00

103 lines
2.9 KiB
Python

from threading import Thread
from queue import Queue
from os import mkfifo, remove
from os.path import exists, join
from secrets import token_urlsafe
from collections import namedtuple
from abc import ABC, abstractmethod
class PipeWriterThread(Thread):
def __init__(self, pipe_path):
super().__init__()
self._pipe_path = pipe_path
self._write_queue = Queue()
def write(self, message):
self._write_queue.put(message, block=True)
def run(self):
while True:
message = self._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._write_queue.put(None)
self.join()
class PipeReaderThread(Thread):
_stop_sequence = b'stop_reading'
def __init__(self, pipe_path, message_handler):
super().__init__()
self._message_handler = message_handler
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._message_handler(message)
def stop(self):
with open(self._pipe_path, 'wb') as pipe:
pipe.write(self._stop_sequence)
self.join()
class PipeHandler:
def __init__(self, *pipe_paths):
self._pipe_paths = pipe_paths
def recreate(self):
self.remove()
for pipe_path in self._pipe_paths:
mkfifo(pipe_path)
def remove(self):
for pipe_path in self._pipe_paths:
if exists(pipe_path):
remove(pipe_path)
class PipeIOServer(ABC):
def __init__(self, in_pipe=None, out_pipe=None):
self.in_pipe, self.out_pipe = in_pipe, out_pipe
self._create_pipes()
io_threads_dict = {
'reader': PipeReaderThread(self.in_pipe, self._handle_message),
'writer': PipeWriterThread(self.out_pipe)
}
IOThreadsTuple = namedtuple('IOThreadsTuple', sorted(io_threads_dict.keys()))
self._io_threads = IOThreadsTuple(**io_threads_dict)
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, self.out_pipe).recreate()
@abstractmethod
def _handle_message(self, message):
raise NotImplementedError()
def send(self, message):
self._io_threads.writer.write(message)
def run(self):
for thread in self._io_threads:
thread.start()
def stop(self):
for thread in self._io_threads:
thread.stop()
PipeHandler(self.in_pipe, self.out_pipe).remove()