stable/freqtrade/rpc/api_server/uvicorn_threaded.py

import contextlib
import threading
import time

import uvicorn


class UvicornServer(uvicorn.Server):
    """
    Multithreaded server - as found in https://github.com/encode/uvicorn/issues/742

    Removed install_signal_handlers() override based on changes from this commit:
        https://github.com/encode/uvicorn/commit/ce2ef45a9109df8eae038c0ec323eb63d644cbc6

    Cannot rely on asyncio.get_event_loop() to create new event loop because of this check:
        https://github.com/python/cpython/blob/4d7f11e05731f67fd2c07ec2972c6cb9861d52be/Lib/asyncio/events.py#L638

    Fix by overriding run() and forcing creation of new event loop if uvloop is available
    """

    def run(self, sockets=None):
        import asyncio

        """
        Parent implementation calls self.config.setup_event_loop(),
            but we need to create uvloop event loop manually
        """
        try:
            import uvloop  # noqa
        except ImportError:  # pragma: no cover
            from uvicorn.loops.asyncio import asyncio_setup
            asyncio_setup()
        else:
            asyncio.set_event_loop(uvloop.new_event_loop())

        loop = asyncio.get_event_loop()
        loop.run_until_complete(self.serve(sockets=sockets))

    @contextlib.contextmanager
    def run_in_thread(self):
        self.thread = threading.Thread(target=self.run)
        self.thread.start()
        while not self.started:
            time.sleep(1e-3)

    def cleanup(self):
        self.should_exit = True
        self.thread.join()