Asyncio within a thread

[hollymcr]

I'm new to asyncio and I'm trying to understand how to incorporate it into a thread.

What I need to do is add a web server with websockets into an existing application. That is, the existing application will continue to function as it already does, but additionally, a web server will run in a separate thread providing access to some of the data from the application via a web browser, and also periodically pushing data to the web browser via web sockets. All the examples I can find seem to assume that the web server is the only thing that the entire application needs to do.

I have a very simple test application below, based on the example in the docs as well as the best write-up on asyncio I have found so far. It has a couple of issues:

1. It doesn't terminate cleanly ("Task was destroyed but it is pending!") when I kill the script via Ctrl-C
   
2. I can't see how to push data into the thread's loop
   

Am I heading in completely the wrong direction, or am I close?

import asyncio import threading from aiohttp import web import time async def wshandler(request): ws = web.WebSocketResponse() await ws.prepare(request) async for msg in ws: if msg.type == web.MsgType.text: x = "Hello, {}".format(msg.data) print(x) await ws.send_str(x) elif msg.type == web.MsgType.binary: await ws.send_bytes(msg.data) elif msg.type == web.MsgType.close: break return ws async def handler(request): name = request.match_info.get('name', "Anonymous") text = "Hello, " + name return web.Response(text=text) async def init(loop): global srv app = web.Application(loop=loop) app.router.add_get('/ws', wshandler) app.router.add_get('/', handler) app.router.add_get('/{name}', handler) srv = await loop.create_server(app.make_handler(), '0.0.0.0', 8080) print("Server started at http://127.0.0.1:8080") return srv def test(loop): loop.run_until_complete(init(loop)) loop.run_forever() loop = asyncio.new_event_loop() t = threading.Thread(target=test,args=(loop,)) try: t.start() while True: print('.', end='', flush=True) time.sleep(1) except KeyboardInterrupt: loop.stop()

[wavic]

except KeyboardInterrupt: loop.stop() loop.close()

Does this work?

[hollymcr]

except KeyboardInterrupt: loop.stop() loop.close()

Does this work?

Error:
RuntimeError: Cannot close a running event loop asyncio: Task was destroyed but it is pending!