sanic/examples/run_async_advanced.py

import asyncio

from signal import SIGINT, signal

import uvloop

from sanic import Sanic, response
from sanic.server import AsyncioServer


app = Sanic("Example")


@app.before_server_start
async def before_server_start(app, loop):
    print("Async Server starting")


@app.after_server_start
async def after_server_start(app, loop):
    print("Async Server started")


@app.before_server_stop
async def before_server_stop(app, loop):
    print("Async Server stopping")


@app.after_server_stop
async def after_server_stop(app, loop):
    print("Async Server stopped")


@app.route("/")
async def test(request):
    return response.json({"answer": "42"})


if __name__ == "__main__":
    asyncio.set_event_loop(uvloop.new_event_loop())
    serv_coro = app.create_server(
        host="0.0.0.0", port=8000, return_asyncio_server=True
    )
    loop = asyncio.get_event_loop()
    serv_task = asyncio.ensure_future(serv_coro, loop=loop)
    signal(SIGINT, lambda s, f: loop.stop())
    server: AsyncioServer = loop.run_until_complete(serv_task)
    loop.run_until_complete(server.startup())

    # When using app.run(), this actually triggers before the serv_coro.
    # But, in this example, we are using the convenience method, even if it is
    # out of order.
    loop.run_until_complete(server.before_start())
    loop.run_until_complete(server.after_start())
    try:
        loop.run_forever()
    except KeyboardInterrupt:
        loop.stop()
    finally:
        loop.run_until_complete(server.before_stop())

        # Wait for server to close
        close_task = server.close()
        loop.run_until_complete(close_task)

        # Complete all tasks on the loop
        for connection in server.connections:
            connection.close_if_idle()
        loop.run_until_complete(server.after_stop())