我需要为每个GRPC请求调用celery任务，并返回结果。 在默认的GRPC实现中，每个请求都在与线程池的单独线程中处理。
在我的情况下，服务器应该以每秒批处理模式处理~400个请求。因此，由于批处理，一个请求可能必须等待1秒才能得到结果，这意味着线程池的大小必须大于400才能避免阻塞。
这可以异步完成吗？ 非常感谢。
class EventReporting(ss_pb2.BetaEventReportingServicer, ss_pb2.BetaDeviceMgtServicer):
def ReportEvent(self, request, context):
res = tasks.add.delay(1,2)
result = res.get() ->here i have to block
return ss_pb2.GeneralReply(message='Hello, %s!' % result.message)
答案 0 :(得分：9)
如@Michael在评论中所述，从1.32版开始，gRPC现在在其Python API中支持asyncio。如果您使用的是早期版本，则仍可以通过实验性API from grpc.experimental import aio使用asyncio API。异步hello world example也已添加到gRPC存储库中。以下代码是示例服务器的副本：
import logging
import asyncio
from grpc import aio
import helloworld_pb2
import helloworld_pb2_grpc
class Greeter(helloworld_pb2_grpc.GreeterServicer):
async def SayHello(self, request, context):
return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)
async def serve():
server = aio.server()
helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
listen_addr = '[::]:50051'
server.add_insecure_port(listen_addr)
logging.info("Starting server on %s", listen_addr)
await server.start()
await server.wait_for_termination()
if __name__ == '__main__':
logging.basicConfig(level=logging.INFO)
asyncio.run(serve())
有关如何实现客户端的信息，请参见my other answer。
答案 1 :(得分：5)
在我看来是很好的简单实现async grpc服务器，就像基于aiohttp的http一样。
import asyncio
from concurrent import futures
import functools
import inspect
import threading
from grpc import _server
def _loop_mgr(loop: asyncio.AbstractEventLoop):
asyncio.set_event_loop(loop)
loop.run_forever()
# If we reach here, the loop was stopped.
# We should gather any remaining tasks and finish them.
pending = asyncio.Task.all_tasks(loop=loop)
if pending:
loop.run_until_complete(asyncio.gather(*pending))
class AsyncioExecutor(futures.Executor):
def __init__(self, *, loop=None):
super().__init__()
self._shutdown = False
self._loop = loop or asyncio.get_event_loop()
self._thread = threading.Thread(target=_loop_mgr, args=(self._loop,),
daemon=True)
self._thread.start()
def submit(self, fn, *args, **kwargs):
if self._shutdown:
raise RuntimeError('Cannot schedule new futures after shutdown')
if not self._loop.is_running():
raise RuntimeError("Loop must be started before any function can "
"be submitted")
if inspect.iscoroutinefunction(fn):
coro = fn(*args, **kwargs)
return asyncio.run_coroutine_threadsafe(coro, self._loop)
else:
func = functools.partial(fn, *args, **kwargs)
return self._loop.run_in_executor(None, func)
def shutdown(self, wait=True):
self._loop.stop()
self._shutdown = True
if wait:
self._thread.join()
# --------------------------------------------------------------------------- #
async def _call_behavior(rpc_event, state, behavior, argument, request_deserializer):
context = _server._Context(rpc_event, state, request_deserializer)
try:
return await behavior(argument, context), True
except Exception as e: # pylint: disable=broad-except
with state.condition:
if e not in state.rpc_errors:
details = 'Exception calling application: {}'.format(e)
_server.logging.exception(details)
_server._abort(state, rpc_event.operation_call,
_server.cygrpc.StatusCode.unknown, _server._common.encode(details))
return None, False
async def _take_response_from_response_iterator(rpc_event, state, response_iterator):
try:
return await response_iterator.__anext__(), True
except StopAsyncIteration:
return None, True
except Exception as e: # pylint: disable=broad-except
with state.condition:
if e not in state.rpc_errors:
details = 'Exception iterating responses: {}'.format(e)
_server.logging.exception(details)
_server._abort(state, rpc_event.operation_call,
_server.cygrpc.StatusCode.unknown, _server._common.encode(details))
return None, False
async def _unary_response_in_pool(rpc_event, state, behavior, argument_thunk,
request_deserializer, response_serializer):
argument = argument_thunk()
if argument is not None:
response, proceed = await _call_behavior(rpc_event, state, behavior,
argument, request_deserializer)
if proceed:
serialized_response = _server._serialize_response(
rpc_event, state, response, response_serializer)
if serialized_response is not None:
_server._status(rpc_event, state, serialized_response)
async def _stream_response_in_pool(rpc_event, state, behavior, argument_thunk,
request_deserializer, response_serializer):
argument = argument_thunk()
if argument is not None:
# Notice this calls the normal `_call_behavior` not the awaitable version.
response_iterator, proceed = _server._call_behavior(
rpc_event, state, behavior, argument, request_deserializer)
if proceed:
while True:
response, proceed = await _take_response_from_response_iterator(
rpc_event, state, response_iterator)
if proceed:
if response is None:
_server._status(rpc_event, state, None)
break
else:
serialized_response = _server._serialize_response(
rpc_event, state, response, response_serializer)
print(response)
if serialized_response is not None:
print("Serialized Correctly")
proceed = _server._send_response(rpc_event, state,
serialized_response)
if not proceed:
break
else:
break
else:
break
_server._unary_response_in_pool = _unary_response_in_pool
_server._stream_response_in_pool = _stream_response_in_pool
if __name__ == '__main__':
server = grpc.server(AsyncioExecutor())
# Add Servicer and Start Server Here
链接到原文：
https://gist.github.com/seglberg/0b4487b57b4fd425c56ad72aba9971be
答案 2 :(得分：4)
如果您对res.get的调用可以异步完成（如果使用async关键字定义），则可以异步完成。
While grpc.server says it requires a futures.ThreadPoolExecutor, it will actually work with any futures.Executor that calls the behaviors submitted to it on some thread other than the one on which they were passed。如果您传递给grpc.server一个futures.Executor实现的只使用一个线程来执行对EventReporting.ReportEvent的四百（或更多）个并发调用，您的服务器应该避免那种阻塞你描述的。