async-hook-example.py

class AsyncSocketWrapper:
    # Sockets are wrapped in this simplified class and passed down
    # to the pymongo <=> libmongocrypt integration layer.

    def __init__(self, sockinfo):
        self._sockinfo = sockinfo

    def send(self, buffer):
        # libmongocrypt calls this function on one of its worker threads.
        event = threading.Event()
        loop = asyncio.get_event_loop()        

        def _async_send():
            # On the main thread: do I/O then unblock worker thread
            await loop.sock_sendall(self._sockinfo, buffer)
            event.set()
        
        loop.call_soon(_async_send)
        event.wait()

    def recv(self, to_recv):
        # libmongocrypt calls this function on one of its worker threads.
        event = threading.Event()
        loop = asyncio.get_event_loop()   
        buffer = ""

        def _async_recv():
            # On the main thread: do I/O then unblock worker thread
            buffer = await loop.sock_recv(self._sockinfo, to_recv)
            event.set()
        
        loop.call_soon(_async_recv)
        event.wait()
        return buffer