学习笔记之asyncio — Asynchronous I/O

asyncio — Asynchronous I/O — Python 3.8.5 documentation

• https://docs.python.org/3/library/asyncio.html?highlight=asyncio
• asyncio is a library to write concurrent code using the async/await syntax.
• Coroutines and Tasks — Python 3.8.5 documentation
  • https://docs.python.org/3/library/asyncio-task.html#coroutines-and-tasks
• Event Loop — Python 3.8.5 documentation
  • https://docs.python.org/3/library/asyncio-eventloop.html
  • asyncio.get_event_loop()
    • https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.get_event_loop
    • Get the current event loop.
  • loop.run_until_complete(future)
    • https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.run_until_complete
    • Run until the future (an instance of Future) has completed.
  • loop.run_forever()
    • https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.run_forever
    • Run the event loop until stop() is called.

A guide to using asyncio | Faculty

• https://faculty.ai/blog/a-guide-to-using-asyncio/
• https://github.com/acroz/asyncio-example
• https://github.com/acroz/asyncio-example/blob/master/agent.py

Service monitoring with python asyncio

• https://nosarthur.github.io/coding/2018/12/03/asyncio.html

Python async/await Tutorial

• https://stackabuse.com/python-async-await-tutorial/

Hello World — Asyncio Documentation 0.0 documentation

• https://asyncio.readthedocs.io/en/latest/hello_world.html
• This is a series of examples showing the basics of how to write coroutines and schedule them in the asyncio event loop.

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How to start / stop / run a service ?

import asyncio
import logging
import zmq
import zmq.asyncio


class TestService:

    def __init__(self, url):
        self._url = url

        self._is_running = False
        self._zmq_context = None
        self._socket = None

    def _start(self):
        if self._is_running:
            return

        self._zmq_context = zmq.asyncio.Context()
        self._socket = self._zmq_context.socket(zmq.REP)
        self._socket.bind(self._url)

    def _stop(self):
        if not self._is_running:
            return

        if not self._socket.closed:
            self._socket.close()

    async def _process_message(self, data):
        # Process message here
        return data

    async def _recv_and_process(self):
        # need while loop to keep receiving and processing messages
        while (True):
            msg = await self._socket.recv_multipart()
            reply = await self._process_message(msg)
            await self._socket.send_multipart([reply,])

    def run(self):
        loop = None

        try:
            self._start()

            loop = asyncio.get_event_loop()
            loop.create_task(self._recv_and_process())
            loop.run_forever()

        except Exception as ex:
            logging.error('Error {}'.format(ex))

        finally:
            if loop is not None:
                loop.close()

            self._stop()

python - asyncio.run() cannot be called from a running event loop - Stack Overflow

• https://stackoverflow.com/questions/55409641/asyncio-run-cannot-be-called-from-a-running-event-loop