It doesn't work if an interceptor intercepts the responses.
Considering there is such an interceptor:
def wrapper(iterator):
for entry in iterator:
yield entry
class MyInterceptor(grpc.StreamStreamClientInterceptor):
def intercept_stream_stream(self, continuation, client_call_details,
request_iterator):
return wrapper(continuation(client_call_details, request_iterator))
Well I know I could delegate a method `initial_metadata` to the original
iterator, but unfortunately, I've seen many interceptors written in the way
above, causing that I couldn't retrieve the initial metadata from last
interceptor.
Any idea?
在 2016年4月6日星期三 UTC+8上午9:08:36，Nathaniel Manista写道：
>
> On Tue, Apr 5, 2016 at 9:58 AM, Tang Weiyu <[email protected]
> <javascript:>> wrote:
>
>> Definition of rpc:
>> rpc telemetrySubscribe(SubscriptionRequest) returns (stream
>> OpenConfigData) {}
>>
>
> What's important here is that the RPC is response-streaming: it will
> return zero, or one, or many more responses.
>
> How to get metadata from client side for streaming type of rpc call?
>>
>> On Mon, Apr 4, 2016 at 5:15 PM, Tang Weiyu <[email protected]
>> <javascript:>> wrote:
>>
>>> Thanks Nathaniel, unfortunately the returned response don't have those 2
>>> methods, though I did get the returned response in the form of stream Type
>>> defined in proto file RCP.
>>> Anything missing here?
>>>
>>> for data,call in stub.Subscribe(sub_req, _TIMEOUT_SECONDS):
>>> metadata = data.initial_metadata()
>>>
>>
> Unpacking the iterator returned by your RPC invocation appears to be a
> mistake here. I suspect that this should be something like:
>
> my_response_iterator = stub.Subscribe(sub_req, _TIMEOUT_SECONDS)
> my_initial_metadata = my_response_iterator.initial_metadata()
> for my_response in my_response_iterator:
> <take some action for each response value>
> my_terminal_metadata = my_response_iterator.terminal_metadata()
>
> Again, the critical part is that the RPC is response-streaming - the code
> for a response-unary RPC would look very different.
> -N
>
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