Source code for

import argparse

from typing import TYPE_CHECKING, AsyncIterator

from .base import BaseStreamer
from ...types.message import Message

__all__ = ['ZmqGatewayStreamer', 'GrpcGatewayStreamer']

    from ..grpc import Grpclet
    from ...types.request import Request, Response

class GatewayStreamer(BaseStreamer):
    """Streamer used at Gateway to stream requests/responses to/from Executors"""

    def _convert_to_message(self, request: 'Request') -> Message:
        """Convert `Request` to `Message`

        :param request: current request in the iterator
        :return: Message object
        return Message(None, request, 'gateway', **vars(self.args))

    async def stream(self, request_iterator, *args) -> AsyncIterator['Request']:
        stream requests from client iterator and stream responses back.

        :param request_iterator: iterator of requests
        :param args: positional arguments
        :yield: responses from Executors
        if self.receive_task.done():
            raise RuntimeError('receive task not running, can not send messages')

        async_iter: AsyncIterator = (
            self._stream_requests_with_prefetch(request_iterator, self.args.prefetch)
            if self.args.prefetch > 0
            else self._stream_requests(request_iterator)

        async for response in async_iter:
            yield response

    # alias of stream used as a grpc servicer
    Call = stream

[docs]class ZmqGatewayStreamer(GatewayStreamer): """Streamer used at Gateway to stream ZMQ requests/responses to/from Executors""" async def _receive(self): """Await messages back from Executors and process them in the request buffer""" try: while True: response = await self.iolet.recv_message(callback=lambda x: x.response) # during shutdown the socket will return None if response is None: break self._handle_response(response) finally: if self.request_buffer: self.logger.warning( f'{self.__class__.__name__} closed, cancelling all outstanding requests' ) for future in self.request_buffer.values(): future.cancel() self.request_buffer.clear()
[docs]class GrpcGatewayStreamer(GatewayStreamer): """Streamer used at Gateway to stream GRPC requests/responses to/from Executors""" def __init__(self, args: argparse.Namespace, iolet: 'Grpclet'): super().__init__(args, iolet) self.iolet.callback = lambda response: self._handle_response(response.request) async def _receive(self): """Start grpclet and await termination :return: await iolet start """ return await self.iolet.start() async def _handle_response(self, response: 'Response'): """ Async version of parents handle_response function :param response: message received from grpclet callback """ super()._handle_response(response)