baseimage-tutorial-framework/tfw/components/pipe_io/pipe_io_server/pipe_writer_thread.py

51 lines
1.5 KiB
Python

from contextlib import suppress
from os import O_NONBLOCK, O_RDONLY, close
from os import open as osopen
from threading import Thread
from .terminate_process_on_failure import terminate_process_on_failure
from .deque import Deque
class PipeWriterThread(Thread):
def __init__(self, pipe_path, stop_event):
super().__init__(daemon=True)
self._pipe_path = pipe_path
self._stop_event = stop_event
self._write_queue = Deque()
def write(self, message):
self._write_queue.push(message)
@terminate_process_on_failure
def run(self):
with self._open() as pipe:
while True:
message = self._write_queue.pop()
if message is None:
self._stop_event.set()
break
try:
pipe.write(message + b'\n')
pipe.flush()
except BrokenPipeError:
try: # pipe was reopened, close() flushed the message
pipe.close()
except BrokenPipeError: # close() discarded the message
self._write_queue.push_front(message)
pipe = self._open()
def _open(self):
return open(self._pipe_path, 'wb')
def stop(self):
while self.is_alive():
self._unblock()
self.join()
def _unblock(self):
with suppress(OSError):
fd = osopen(self._pipe_path, O_RDONLY | O_NONBLOCK)
self._write_queue.push_front(None)
close(fd)