Send data to a multiprocessing.Process running an asyncio event loop

worker.py

# A rare scenario: Communicate to a child process that's running an event loop

import asyncio
from asyncio import StreamReader, StreamReaderProtocol
from multiprocessing import Process
import os

class Worker:
  def __init__(self):
    self.read_fd, self.write_fd = os.pipe()
    self.writer = os.fdopen(self.write_fd, 'wb', 0)

  def start(self):
    os.set_inheritable(self.read_fd, True)
    Process(target=Worker.worker, 
            args=(self.read_fd, )) \
            .start()
    os.close(self.read_fd)
  
  @staticmethod
  async def do_task(task_number):
    pass

  @staticmethod
  async def accept_tasks(read_fd):
    loop = asyncio.get_running_loop()
    reader = StreamReader()
    protocol = lambda: StreamReaderProtocol(reader)
    transport, _ = await loop.connect_read_pipe(
      protocol, os.fdopen(read_fd, 'rb', 0))

    while True:
        task_number = int(await reader.readline())
        loop.create_task(Worker.do_task(task_number))

    transport.close()
  
  @staticmethod
  def worker(read_fd):
    loop = asyncio.get_event_loop()
    loop.run_until_complete(Worker.accept_tasks(read_fd))

  def add(self, task):
    self.writer.write((str(task) + '\n').encode())


worker = Worker()
worker.start()
worker.add('1')
worker.add('2')