On Mon, Feb 6, 2017 at 1:19 PM, Michael Bond <[email protected]>
wrote:
> Thanks for the quick reply. Should of specified that the code in the
> original post is a snippet, there's receiving logic underneath it.
>
> Some more details surrounding this. In this case I have a callback
> function on the server (written in python) that needs to be executed to
> free resources, so closing the sending portion does not seems to trigger
> that. Also the client in this case dictates all connections. The server
> simply pours a stream of data to the client until the client no longer
> needs that particular data. So to be more specific with my question how
> would I fully close the stream from the client's side?
>
Not sure I follow 100%. But the python code should have similar logic where
it is receiving the request messages. When the client half-closes the
stream, the server would get EOF trying to receive (or if python APIs were
async/push, like the Java APIs are, you'd get an "end of stream"
notification). Is that where you are doing the clean up?
>
> On Monday, February 6, 2017 at 9:50:04 AM UTC-6, Josh Humphries wrote:
>>
>> Perhaps more helpful: in your code example, you would then consume the
>> responses by calling Recv() on the stream until it returns an error (io.EOF
>> on successful end of stream or some other error if the call fails). Even if
>> you are not expecting any response data from the server, you want to call
>> Recv() in order to learn the ultimate disposition of the call (did it
>> result in an error in the server or was it processed successfully?).
>>
>> log.Println("stream starting")
>> streamCtx, cancel := context.WithCancel(ctx)
>> defer cancel()
>> stream, err := grpcStream(streamCtx, otherArgs)
>> if err != nil {
>> errCh <- err
>> return
>> }
>> defer stream.CloseSend()
>> defer log.Println("closing stream")
>> for {
>> msg, err := stream.Recv()
>> if err == io.EOF {
>> break
>> }
>> if err != nil {
>> errCh <- err
>> return
>> }
>> }
>>
>>
>> ----
>>
>> Josh Humphries
>>
>> FullStory <https://www.fullstory.com/> | Atlanta, GA
>>
>> Software Engineer
>>
>> [email protected]
>>
>> On Mon, Feb 6, 2017 at 10:36 AM, Josh Humphries <[email protected]>
>> wrote:
>>
>>> On the client, the CloseSend method is "half-closing" the stream. So it
>>> closes the request/upload half of the stream. The stream remains open until
>>> the server closes the other half: the response/download part of the stream.
>>> Cancelling the stream also closes it (as would the channel being
>>> disconnected or the call timing out).
>>>
>>>
>>>
>>> ----
>>>
>>> Josh Humphries
>>>
>>> FullStory <https://www.fullstory.com/> | Atlanta, GA
>>>
>>> Software Engineer
>>>
>>> [email protected]
>>>
>>> On Mon, Feb 6, 2017 at 10:29 AM, Michael Bond <[email protected]>
>>> wrote:
>>>
>>>> Hey, trying to make sure I'm doing this correctly.
>>>>
>>>> Right now I'm having issues with closing streams started with a context
>>>> that is passed around and exists for quite awhile.
>>>>
>>>> In this example "ctx" is passed around to many go routines, I want to
>>>> keep "ctx" around but passing it to "grpcStream" seems to keep the stream
>>>> from actually closing. What I did below fixed the issue but I wanted to
>>>> know if it is needed to pass a child context and cancel it for the stream
>>>> to actually close. Is CloseSend() not sufficient if the context is still
>>>> alive?
>>>>
>>>> log.Println("stream starting")
>>>> streamCtx, cancel := context.WithCancel(ctx)
>>>> defer cancel()
>>>> stream, err := grpcStream(streamCtx, otherArgs)
>>>> if err != nil {
>>>> errCh <- err
>>>> return
>>>> }
>>>> defer stream.CloseSend()
>>>> defer log.Println("closing stream")
>>>>
>>>> Thanks!
>>>>
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>>>
>>
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