我想每个人都知道如何处理django中长期运行的任务：使用芹菜和放松。但是如果我想通过aiohttp（或龙卷风）获得websockets的好处呢？
假设我有很多CPU绑定任务，可能需要几秒钟到多个（5-10）分钟。在websocket循环中处理此任务并通知用户进度似乎是个好主意。没有ajax请求，对短任务的响应非常快。
async def websocket_handler(request):
ws = web.WebSocketResponse()
await ws.prepare(request)
async for msg in ws:
if msg.tp == aiohttp.MsgType.text:
answer_to_the_ultimate_question_of_life_the_universe_and_everything =\
long_running_task(msg.data, NotificationHelper(ws))
ws.send_str(json.dumps({
'action': 'got-answer',
'data': answer_to_the_ultimate_question_of_life_the_universe_and_everything,
}))
return ws
但另一方面，按照我的理解，以这种方式提供服务的CPU绑定任务会阻塞整个线程。如果我有10名工作人员和11名想要使用应用程序的客户，则在完成第一个客户的任务之前，将不会提供第11个客户端。
也许，我应该在celery中运行看起来很大的任务，在主循环中运行看起来很小的任务？
所以，我的问题是：是否有任何良好的设计模式用于为异步服务器提供长期运行的任务？
谢谢！
答案 0 :(得分：8)
Just run your long-running CPU-bound task by <iframe height="400" width="600" id="multGame" src="http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_six.xml"></iframe>
<select id="timestableSlt" onchange="changeGame()">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6" selected="selected">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
</select>
<script>
function changeGame() {
var e = document.getElementById("timestableSlt");
var strUser = e.options[e.selectedIndex].text;
if (strUser = "1") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_one.xml";
} else if (strUser = "2") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_two.xml";
} else if (strUser = "3") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_three.xml";
} else if (strUser = "4") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_four.xml";
} else if (strUser = "5") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_five.xml";
} else if (strUser = "7") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_seven.xml";
} else if (strUser = "8") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_eight.xml";
} else if (strUser = "9") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_nine.xml";
} else if (strUser = "10") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_ten.xml";
} else if (strUser = "11") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_eleven.xml";
} else if (strUser = "12") {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_twelve.xml";
} else {
document.getElementById('multGame').src = "http://www.learninggamesforkids.com/_games/Main.swf?xml=assets/fill_in_blanks/fillitin_mult_six.xml";
}
}
</script>
and send progress notifications by loop.run_in_executor().
If your job is not CPU but IO bound (sending emails for example) you may create a new task by loop.call_soon_threadsafe() call. It looks like spawning new thread.
If you cannot use fire-and-forget approach you need to use persistent message broker like RabbitMQ (there is https://github.com/benjamin-hodgson/asynqp library for communicating with Rabbit in asyncio way).