python grpc 異常 Received message larger than max (5009675 vs. 4194304) 處理

在使用Python 搭建gprc框架時，遇到傳輸文件大小限制，異常信息如下：

Traceback (most recent call last):
  File "/grpc_demo/demo_client.py", line 47, in <module>
    run("localhost:18991", ".")
  File "/grpc_demo/demo_client.py", line 29, in run
    response = stub.CreateFile(demo_pb2.FileRequest(file=data, name='ffile.jpg'.encode('utf-8'), rpath=rpath.encode('utf-8')))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/grpc/_channel.py", line 826, in __call__
    return _end_unary_response_blocking(state, call, False, None)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/grpc/_channel.py", line 729, in _end_unary_response_blocking
    raise _InactiveRpcError(state)
grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
	status = StatusCode.RESOURCE_EXHAUSTED
	details = "Received message larger than max (5009675 vs. 4194304)"
	debug_error_string = "{"created":"@1593481044.082878000","description":"Error received from peer ipv6:[::1]:18991","file":"src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Received message larger than max (5009675 vs. 4194304)","grpc_status":8}"
>

這是因爲grpc默認傳輸文件大小爲4*1024*1024 也就是4兆，超出此大小便會拋出StatusCode.RESOURCE_EXHAUSTED這個異常，解決此問題需要修改默認傳輸大小限制。查閱各種資料，發現大多爲golang版本的解決方案，經過摸索測試，發現如下解決方案：

在server創建時添加options參數：

MAX_MESSAGE_LENGTH = 256*1024*1024  # 可根據具體需求設置，此處設爲256M
server = grpc.server(futures.ThreadPoolExecutor(max_workers=10), options=[
               ('grpc.max_send_message_length', MAX_MESSAGE_LENGTH),
               ('grpc.max_receive_message_length', MAX_MESSAGE_LENGTH),
               ]
        )

只需將服務端設置便可。